Is it worth it?
 

I'm not sure if this is the right spot for this but I would like to get some feedback from some pros. I'm currently in a bit of dilemma of deciding of going back to get a MS (or Phd) or try and get a job in the CFD arena.

I currently have no experience in CFD other than taking a few courses in numerical HT courses (soon will be getting into CFD) but would love to get into it. I have talked to professors and they say there is a demand for it. Is this true? I'm finding it difficult to find an entry level position just get my foot in the door and I thought that my lack of training might taken away if i go ahead and get my advanced degree. Does anybody have any suggestions?

Thanks Jason

Re: Is it worth it?
 

(1). To answer your question about " Is it worth it? ", I have to say " No ". (2). This is based on several factors. I will explain it in just a few moment. (3). As for getting a job, I would like to share with you my son's comment. He used to say, " Even if the un-employment rate hit 10%, there are still 90% of people working ." (90% of working people working) So, if you decide to spend 4 more years to study CFD, it is also all right. (4). Now back to the real world. In the era before 90's, the major industries hiring CFD engineers are aerospace related companies and government laboratories, such as airframe companies, Boeing, Lockheed, Rockwell, Northrop, Grumann, General Dynamics, McDonnel-Douglas, TRW, etc.. and engine companies, such as GE, P&W, Lycoming, AlliedSignal,..etc and NASA/ Ames, Langley, Lewis,.. Now you can feel the size of the industries and government labs. These companies and labs all have their own dedicated department to do CFD. (5). Through 10 years of cut back, there are only two airframe companies remain. And with the government order for aircraft reduced, and with the global Asian economic crisis, even the remaining commercial aircraft company has to seek help from government for help in foreign competition. Now you are getting the tough picture. (6). So, even if there are positions in CFD available, the experienced CFD engineers will be able to get the job first, not mentioning the thousands of displaced experienced engineer looking for opportunities to come back. Now, the situation is really impossible. (7). In 90's, the trend has been for the CFD engineers to become their own boss, as consultants, consulting company, and CFD vendors,...or even as 3-D modellers for animation industries. And I am sure that some CFD developers or vendors were at some time in the past employee of aerospace companies. (8). Unless somehow US gets involved in the future world war 3, or somehow the global or Asian economy suddenly change the direction, the picture will remain the same. And the CFD job will be hard to find. (does not mean there will be no CFD jobs) (9). The other factor is because of the isolation of universities and the defense industries, the real contents of CFD in industries were not fully understood by the universities. This makes the matching difficult between the student and the industries. (professors did not know exactly what the engineers in industries were doing.) And even in the industries, there are two lines of thinking; one is the traditional and one is the CFD oriented. This was all ri;ght when the business or industries were booming. When the time is tough, the CFD part is usually the first to cut. (it is not mature and so it is not essential.) (10). Now with some commercial CFD codes becoming more mature, companies are hiring engineers just to model the problem and run the codes. (11). Well, I think, the Internet related services are the current and the future job market. In the capitalist countries, the need from the market is essential. (12). You have to learn how to survive first. If you love fluid dynamics and CFD, then you can ignore my comment completely. (I loved to build model airplanes and small rockets when I was a small child, long before the Appolo and Sputnik programs. CFD is a field for those who really like to work with computer programming, numerical methods, thermo/fluid dynamics. But the major driving force behind is long gone. It is much easier to get in the Internet related field because the support is everywhere.(both money and the problems)

Re: job scene
 

So, CFD -code development is saturated. Industries are just wanting people who can run the existing codes and model their problems. Agreed universities are not aware of what's going on in industry.

But somewhere ( even without the world war III or Asian crisis..turning things upside down) ..'the already existing NEW techniques in academia' may seep into industry overnight. Example ..if lattice boltzmann techniques could Shape companies like EXA...how far are 'spectral elements'.. How long will it take 'lower dimensional models' to find a place in industry..?

I feel ..if nothing a good CFD specialist can at least end up at some convenient place in the 'SIMULATION' industry applying ( again at least) a part of his computational skills in his/her job.

So..why NOT CFD ? ( even in the worst case scenario..)

Prabhu

Re: job scene
 

(1). It has nothing to do with CFD , or the potential of CFD, or even the plan to study CFD. There is nothing wrong with these issues. The issue is related to the investment in a MS or PhD degree and getting a job in CFD. (2). As is today, many number-one, number-two companies in the country, or in the whole world, are still struggling with 20 some years old codes, 1-D ,2-D or inviscid codes. (3). And so far up to now, I have not found any commercial CFD codes which can really make a positive contribution on the design of products or understanding of physical phenomenon relevant to the improvement of product design. (4). If any such fact exists, it is because of the engineer's insight of the problem and his understanding of the fluid dynamics. Yes, the CFD codes have been used for a long time in industries (aerospace industries), but they were carried out systematically along with endless testing of hardware. Not mentioning the hardware testings specifically designed to fine tune the CFD codes. (5). It was possible, because such support were available in those days. Without such support, it requires a magic word "love". " Love in CFD" is essential for survival, if the person understands the "love" part and the "CFD" part correctly. (6). For Internet field, even if a company is not making money, and even if everyone knows it, they still put the money in the Internet stocks. On the other hand, even if one has created a super-fast CFD code, he still has to convince a lot people to use the method in the CFD code. (7). Progress in CFD still will be made by some researchers ,regardless of the future job market need. (8). You can open the ASME magazine and do some research for the last five years in terms of the number of CFD jobs listed in the number-one mechanical engineering magazine. You would be very disappointed if you look into the AIAA's Aerospace magazine. (9). Anyway, there are still some CFD jobs around to do modeling in automotive industries, electronics equipment,...etc. But, these jobs are really very specific. The abilities of a young PhD to make a significant contributions in these areas are limited. (10). As a matter of fact, the published technology should be able to let the CFD to make a much bigger impact on many fields. Unfortunately, it requires a smart engineer with a good supporting environment to achieve this. When you have to worry about the monthly house mortgage payment, CFD simply does not exist at all in the daily activity list. ( A couple of years ago, a friend said to me that one of his friend was studying to be a dentist and same time helping an engine company as a summer job worker. My friend and his friend used to work for an engine company which in no longer on the map. (11). So, based on his friend's experience, dentist job seems to be a better choice in this unstable world. Is the number of CFD researchers larger than the population of whales?

Re: Is it worth it?
 

I have possibly gotten a promotion in my current company doing R&D work. It is a very good opportunity for my career and COULD possibly lead into doing FEA in heat transfer. But then again it may not..I know everyone has heard that more Americans are not going to Grad school and my way of thinking leads me to believe that I will be more marketable in the long run if I did go. At what point does it make sense that a person should get an advanced degree.

A friend of mine went ahead and got an MSEE and is making about 20k more than I am... I also know several others that are getting more because they have advanced degrees even though I have been working in the industry instead of getting my advanced degree. I thought that the working engineer would make just as much (maybe a little lower) than the one who has an advanced degree.

It seems we are lied too in engineering school about pay and job markets. It took me 6 months to find a job and still got paid minimally when I did find one. I do agree that getting an MS/Phd is risky, especially with the economy the way it is jumping around, but aren't those with the higher degree usually last to get the axe because of their knowledge base?

Re: Is it worth it?
 

(1).If you decide to go to the graduate school, you must do it as soon as possible. In the school, you also like to attend the one which will give you the degree as soon as possible. Some schools will take you 6 to seven years or even more to get a PhD degree. Also a degree has nothing to do with your actual knowledge at all. Actually, you can get a MS degree in a year and a half. And for those who take time to get a degree when working at the same time, normally do not get a salary raise at all after they obtain the degree. (2). There is probably a standard difference in salary between a BS and a MS engineer. But this is normally because the one with a MS degree must invest both the time and the money first, in order to get the degree. So, they have to get higher salary otherwise there is no incentive to get an advanced degree. (3). Going bach to school is not going to make you more intelligent or more experienced. The advantage of going back to school is that you will have the opportunity to learn some principles which you can use after graduation. In other words, it will open one more door for you. Whether you will succeed or not, it all depends on your effort. (4). In the information age, if you have learned how to get the necessary information and be able to digest it, normally you don't have to go back to school. This is why Bill Gates was able to succeed in the PC software field. Formally, he did not graduate from Harvard University many years ago. (that is my impression, I could be wrong.) (5). If you are interested in making money, you must get into Business field. That is the field where one is suppose to make a lot of money. (6). Beyond this point, it is difficult for me to give you any advice. My suggestion is : If you are interested in getting an advanced degree, then do it as soon as possible and finish it in the shortest possible time. A degree is a degree, it has nothing to do with your ability to solve problems, to make more money or become smarter. But if you make good use of the principles learned at school after graduation, it will help you to achieve more. ( but it is not free. I have a PhD degree, and I have been working hard day and night in order to survive in the rapid changing world. So, I actually put in twice amount of effort into the CFD related work. So, a slightly more in salary is fairly normal.) There is no direct relationship between a degree and his performance. The same is true between his performance and his salary. ( In social science, you can delay the time to go back to school. In math, physics, engineering, it is very important to get your degree as early as possible. )

Re: Is it worth it?
 

A very good question.

What do you want in life? Education is about more than just making more money, it is about broadening the mind and the experiences which bring that about. Grad school can be a blast and a FUNDAMENTAL change in the way you think about problem solving or it can be the biggest waste of time in the world! I have had both experiences one was with a weak and narrow minded conformist moron the other (which I had to pay for myself) got me to work and study in Germany, I learned German made life-long friendships, had a blast as a teaching assistant, on and on!

The primary factors are supervisor, topic, and University.....and arguably only the supervisor is key becasue the good ones will have the other two figured out!

I don't agree AT ALL with John's comments the you should just finish as fast as possible and it does not make any difference what you do! True, these 8yr PhD's are a discrace! But come on now John what you are saying is paramount to saying: "Why not just lie about it on your resume and hope that nobody catches on"! Most really good profs will get you through in the 3-4 year range (that means really done, defended, corrected, etc not oh, now you can start writing up at 4 yrs...which will wind up to be 5) and 3-4 is probably how long it took them! But do look into any unusual time lengths and why...slave labour is common in grad schools!

good luck...............................Duane

Re: Is it worth it?
 

(1). It was purely based on the financial consideration. (2). If you stay in the graduate school for too long, even with the salary increase after graduation, it is going to take a long time to pay off the loan.

Re: Is it worth it?
 

First of all, you've got to appreciate John Chien's point of view. If you read many of his postings, you'll see a couple of repeated ideas 1) All comercial codes are worthless except in very specific applications 2) Anyone who uses computational codes without first having trudged through the creation of their own FORTRAN (or some other equally arcane language) programs can offer nothing to "real-world" industry, and 3) Current commercial codes offer nothing to the design cycle.

Well, everyone's welcome to their opinion.

I can tell you that I routinely use a very user-friendly, general commercial code, CFDesign, to save my company money and time. I design balanced airflow systems for electric vehicle battery packs. The airflow paths for these systems need to deliver equal cooling to all the batteries while minimizing pressure drops. I would guess that the use of CFD has saved 3 prototype iterations over the old "trial and error" system. That means less money on the experimental build floor. More importantly, that means a shorter design cycle. Believe me, any ignorant manager can be sold on CFD by those last two statements alone.

Here's another way to think of it: if commercial CFD isn't a good design tool, why are there so many commerical codes advertised in the header of this forum? Who's supporting this market?

By the way, I am a BSME. I've started my Masters on a part-time basis. I see no reason to rush through it. As for an advanced degree: I recomend you work for 1-2 years if you are unsure of a field of study. How pointless to get a degree in something you may end up not liking. Maybe you'll find something in Industry that you really love! If not, at least your paying off some of your undergrad loans along the way.

Sorry about the long-winded report. I'll stop now and cover my head in anticipation of John's reply.

Jeff W

Re: Is it worth it?
 

(1). I am reading your comments, and I am reviewing the OpenGL programming guide, and I am watching this second part of the movie about passengers missing in an airplane. See, I am very busy. (2). So far, on this forum, there are only two persons like you who have claimed that the commercial codes are useful tools for their work. The other person was related to the thermal design of power supply with a fan and a couple of heat sinks. I am very happy to hear that because of your confidence. So, you have to continue on your good work. (3). I can only mention an example of real world example, that is about the story of day-trader in the stock market. For someone who is very cool, he can still make a lot of money through day-trading. That was the conculsion of the study. So, you and the other person have the same personality, and you don't rush into it. And that is main key to the success. So, I don't want you to change your mind about the usefulness of CFD. In this respect, you seem to have qualified under the principle of "love in CFD". The question I have is " as a user of this code, can you keep it alive?" "Can you keep the company alive?" " How many copies of code do they have to sell in order to survive?" If you continue on this process, pretty soon you will have the answer. "Do we really need the PC/Pentium III for Internet?, for word processing?, for e-mail?" Based on your logic, Billions of dollars can be saved if we stop using the computers. You can easily save over a thousand dollars by not buying the computer and the software. If you can convince one million people to stop using the PC, you can easily save everybody one Billion dollars. (4). The keybord I am using right now, the monitor I am watching right now, the laser printer I have been using are all purchased in 92 when I was working as a consultant in a foreign country. I did upgrade the mother board and disk drive a couple of times. But still, I am not a good consumer. Me alone can not support the PC industries. (5). So, in order to survive, the PC hardware vendors and PC software vendors must create the new market every year using different methods. And today, you can get a complete PC with 300, 400 MHZ cpu in it for less than 300 and 500 dollars. (6). The CFD code vendors are just like PC software vendors, they all try to survive. They all will come up with very creative methods to sell their products to the consumer. There is nothing wrong with it. (7). I think last year the German goverment passed a law which make the x-rated stuff illegal on Internet. If people think that they are happy and willing to spend money to buy computer and get on Internet, there is nothing wrong with it, right? (8). And even if you said you are getting good results from the commercial CFD code, I am not sure that the solutions you obtained are really accurate solutions. Can you say that your solutions are all accurate within a couple of percent when compared with the test data? Are you willing to provide such benchmark test results? (9). When I say useful CFD codes, I mean a code which can produce reliable and accurate solutions. It also must be repeatable. If a calculator is not repeatable, do you still want to use it? I think, it is likely that you would return it to the shop. (10). But then, how many people have return their slide rules, 30 years ago? I think, the fundamental problem or difference is: the same word or definition has different interpretation , it depends on the time, the location, and the person involved. What I have just said, or said before, are just virtual vehicles for someone to express his opinion.

Re: Is it worth it?
 

John,

Are you being serious? You give a reply to almost every posting on this forum. Sometimes multiple replies in the same thread! Don't you think it's even a little untruthful to say that there are only 2 people on this forum to ever have claimed success with commercial CFD code? What's that crap about being a "Day Trader"? Maybe I'm lack the intelligence, but I don't follow your logic.

Jeff W

Re: Is it worth it?
 

(1). The issue is not logic, the point of discussion is not truth. (2). The goal is to keep the cfd-online forum rolling. (3). In ERCOFTAC Seminar and Workshop on 3D Turbomachinery Flow Prediction V, COST Action F1 Workshop on 3D Navier-Stokes Codes, 6th-10th January 1997 Courchevel,France, in the Open Forum section, it printed:"This opened with a review of the Lectures and the Test Case Sessions by Hirsch. He added to his 'one-lines' from previous years! 1994:Nothing Works, 1996:There is Hope, 1997:Is there Hope? This was with reference to the discrepancies with data, and the difference between different codes with the same physics, e.g. turbulence model. Suggested reasons were: Numerical aspects(especially insufficient grid resolution); Physical modelling(turbulence/transition); Uncertainties in test cases with respect to specification of boundary conditions. Overall we must make progress, not go over old ground again! " (4). I think, in 1999: there is at least one satisfied commercial CFD code user. (5). The story behind the "day-trader" in stock market is: The suggestion from me, the suggestion from you, is just like the suggestion from a day-trader, is not applicable to anyone else. But the forum will provide some reference points, so that a reader can evaluate the suggestions and his background to make a decision ( or no decision at all). So, the forum is to provide " what's available ", not "what should be done". (6). There is an old saying that " a stone from other mountain, can be used to sharpen a file " ( A seemingly useless stone from a far away land, can become a very useful tool to correct the original design and improve the quality of the product.) My words here is just like the CFD code you use.

Re: Is it worth it?
 

Dear Jeff,

Commercial codes have limited applications. But technology is advancing so rapidly and competitions among companies are accelerating so rapidly that no individual company can do monopoly business anymore. In order to stay in cutting edge shape, commercial codes are not enough. It has already been proven that if a company just only rely on commercial softwares, it is obvious that the individual company will be out of business slowly. This is a doggy dog world. One company is putting another company almost out of business to stay on the top. This is a war of technology and profit. The hiring managers are at a loss what to do. They have stress and pressure from the top management. The hiring managers want development as soon as possible to get the product in the market. So they mainly depend on commercial softwares. We need to unlock our door of thoughts. Look what is happening! Say for example, Diesel engine companies got penalty of one billion dollar for producing engines with high emissions problems. Now think how many employees the companies laid off to compensate this loss. Again think of the consequences of profit motivated General Motors. The results brought the company with a 4.9 billion dollar lawsuit. If GM has to pay this amount of money then three to five thousand high level employees have to get early retirements. Prognosis is not satisfactory even if GM survives this time. Everybody is trying to play it safe. In order to bridge the gap between profit and technology, both commercial softwares and advanced code development should proceed simultaneously to keep this earth environmently safe place for us and the next generations to come. Nobody can say what will be worthy and what will be not worthy in the long run. Thank you.

Re: Is it worth it?
 

Heh, you forgot Hirsch's 1998 comment ... "there is progress". I don't know what he said 1999 though.

Note that the test cases used in this workshop are selected because they still pose a big challange to current CFD technologies. There are thousands of other cases where CFD of today works very well and where commercial codes produce very usefull results.

Re: Is it worth it?
 

There will certainly be a demand for qualified CFD engineers in the future. I don't agree at all with the pessimistic comments from others here. The CFD market is growing steadily by approx 20% per year (anyone have any current figures on this? Otherwise, see the thread about this from last year) and as computers become cheaper CFD will find new application areas. I see no sign at all that we have reached the roof.

The strong cut in US defence and governmentally funded R&D that has occured over the last 10 years or so has lead to a temporary over-supply of CFD engineers in the US. It is not surpricing that this generates a lot of frustration and pessimistic forecasts from those who got hurt. In the last few years we have seen a new trend though... many of these NASA and Gov.Lab. guys that got laid off have started their own small companies and there are now many many small CFD companies that all live on commercial grounds. Both small and large companies have started hiring CFD people again.

Whether or not you should go into CFD of course depends on if you are truly interested in it.

Another thing that you might want to think about is if you are interested in numerics, coding and theory or if you are more interested in the application side of CFD. Don't let "the opportunity" make this choice for you.

Re: Is it worth it?
 

(1). The point I was trying to make is: after nearly thirty years of CFD, there was this brave person willing to say that the CFD is not there yet! (2). The commercial CFD codes are about ten years old, they are still teenagers. For them, I think, it is appropriate to say that they have made significant contributions, especially in the areas of user-friendly graphic user interface (GUI), automatic un-structured mesh generation for complex geometry, interactive-adaptive mesh refinement, CAD interfaces ...etc... (3). The concern is that alone is not going to guarantee their survival in the highly competitive world. (4). The real solution is for the forum to create the trend, such that the industries and consumers are willing to invest in the development and applications of CFD.

Re: Is it worth it?
 

Turn! Turn!! Turn!!!

Time has come to open our eyes. Time has come to unlock our door of thoughts and motivations for advancements. We don't want to be carried away anymore like a leaf in the air or by fear of the turbulent phenomena generated by mother nature called 'tornadoes'. We cannot expect to confine ourselves in limitations. God has given us the power to put our heads together to reveal his mysteries. Time is coming for us to even challange mother nature. Technology is summoning us to " Follow knowledge like the sinking stars,

Beyond the utmost bound of human thoughts."

Re: Is it worth it?
 

(1)..... <CFD War> ..... (2). A solider in a battle field, (3). two soliders went in along, (4). three guns fired, and four canons groan, (5). all CFD soliders never come back home...... (6). CFD is a serious business. JC#

interesting
 

Mohammed,

I think I agree with most of what you said. Keep one thing in mind, though: All businesses are "profit motivated". GM is not some power hungry evil empire. It provides good vehicles at good prices to people all over the world. True, GM is facing a large penalty for a supposed design flaw. Never mind the fact that the guy who caused the accident was drunk. Even so, products are designed by Humans. Humans occasionally make mistakes. You will never be able to design for every possible situation. Most design regulations were brought about by flaws that surfaced. They were corrected and recorded to prevent future flaws of the same kind.

1) People need/want cars 2) GM makes cars 3) People pay GM for the cars 4) The profits flow to GM and all its suppliers 5) A lot of people get to eat 3 meals a day

Another thing: competition is good-- without free market competition, technology will grow slowly if at all.

Sorry, I don't subscribe to the communist/socialist idealogy of State (or some other power) controlled trade.

Thanks, Jeff W

Re: interesting
 

(1). why do you think that people are buying Japanese cars? Technology, or economy? (2). Why do you think that companies are producing household products in communist country? To convert them to capitalists or to make money? (3). Do you know why based on the recent report, two US carriers were sent to Taiwan strait to prevent Chinese invasion of Taiwan in 1996? To protect US businessman in China or US security? (4). The answer is: US car manufactures were sleeping when Japanese were investing in car engine technology. The consumers know the difference. (5). The answer is: the companies can reduce the labor force here while making more money in communist country. (6). The answer is: Even if you don't like communist system, there is no way out. Face-to-face, you will have to know how to defend yourself. (7). Those are real-world competition. And we hope that, through this cfd-online forum, you will be able to get a clear picture and learn the real CFD skill. (if you can get your hands on a commercial code, your enemy also can.)

Re: Is it worth it?
 

John, Do you sleep at nights!!!!!

Cheers Mahesh

Re: Is it worth it?
 

It is very wrong to say that commercial CFD quotes do not produce good results. But it always requires user qualified enough to handle these codes. It is this aspect which will force the demands of CFD specialist to rise. In last five years the many new applications areas are opened up for CFD with development of computing power at an affordable level. It is very wrong to say that everything is gloomy for CFD in future. I have a strong conviction it has a very bright future like FEM analysis of structures. Of course the success will be based on commercial packages.

Re: Is it worth it?
 

I have heard that CFD can be useful and lots of money can be made from being an expert in this field.

Re: Is it worth it?
 

(1). A real good question. (2). Why not keep track of the time when I post a message here. (3). In a war, can you sleep? You think people come here to relax to listen to the classical music? To suvrive, one must be able to feel the movement of the CFD world. (4). Recently, I sleep for three hours in the evening, then go back to sleep again at around three in the morning. My watch's two alarm will sound at six am and six fifteen (it has been this way for a long time. ) My alarm radio will give me one hour new from six am, and I will eventually get up around seven forty five for another day's work. (5). I found my brain work better at night. (6). I try not to get too involved here, so I have the full control of the situation. (6). Thank you for your message.

Re: Is it worth it?
 

(1). Let's say the total cost to hire an engineer is 100,000 dollars, and the price of a CFD code license is 10,000 dollars. Then the engineer must be able to find 10 clients ( or one client with 10 licenses) in order to survive. (2). Everyday, 10 engineers in the client companies will be busy solving their problems, the he is going to be very busy supporting them. (3). Do you think that he will be able to provide first class technical support to every user? Do you think he will have time to visit the cfd-online? Do you think he will be able to learn something new in CFD? Do you think he will have the opportunity to fix a bug? Do you think he will have the time to improve the code?

Re: Is it worth it?
 

John, I think you are missing a point here. Most of the CFD codes has active support from the University. Development work is concentrated in Universities (it is cheaper to do so). You can higher a Ph.D student for £15-20K in UK. For support engineer, one can always take him off the job occassionally (say 2 weeks) and train him in latest developments. Once the popularity of the CFD is growing (it is happening), it is most likely to be used for repetitive problems which will require little or no support. If we have trained people (qualified) at industries little or no support will be required.

Re: Is it worth it?
 

And then what! All quiet in the Western Front! Let the sacrifice of a few CFD soldiers bring a new era in CFD development. Is is not still better!

Re: Is it worth it?
 

(1) It is a very important piece of information. (2). What you are saying is, most commercial codes were born in a university by a professor. It is then raised by PhD students, and supported by part-time students? (3). Is it going to stay this way? Does a user of a commercial code understand this? (this is consistent with what I have experienced that sometimes, a support engineer or a user would say "I thought this bug has been fixed for sometimes, but it is still there." (4). I am thinking that there are probably two schools of thought that, one is the software is maintenance free, and the other is the software requires professional support. (5). I think, for a commercial CFD code to be useful, it can only collect fees based on the number of real CFD problems solved, not based on the number of licenses used, if the world is serious about the campus-born CFD codes. But then, I guess one can alway think of a commercial CFD code as a computer game, like tomb raider ?

Re: Is it worth it?
 

(1). Well, I think I like your conclusion......but..... (2). But it doesn't solve the original question: Is it worth it?

Re: Is it worth it?
 

Hello guys,

i've been off for three days and this big (!!) thread pops up. Pardon me if i pirate John's numbering style but i have many points and i want them to be separated. (1) the original message asked if it is worth it going back to school to learn cfd. right know i'm doing just that. i started here doing nonlinear optimisation not cfd related at all. i took CFD courses and they were interesting. you must know fluid mechanics well (an intermediate/advanced course in fluid mechanics/aerodynamics is essential). learning CFD helps you to appreciate and think about fluid mechanics more deeply than traditional fluid mechanics courses because you ignore the silly restrictions (ideal flow, incompressibility, etc) and learn to understand physics. however i don't think that you need a MS or PhD to understand CFD (remember understanding fluid mechanics does not mean you can understand CFD, i'll get back to this later). i feel that i could have gained the undersatnding of CFD through similar courses in undergrad, but most professors are of the mindset that undergrads don't have the background, maturity, or understanding to take courses in computational methods. i disagree. i took a grad course in finite elements (structures) in my senior year and two courses in CFD since i've been in grad school. i feel i could have taken the cfd courses in undergrad with no problems. (2) i think for the professional engineer the best thing to do would be to go to your local university and take some courses part time to learn CFD. grad school (for CFD) isn't worth it unless you are passionate (as John said) or are interested in a very advanced topic like unsteady CFD in turbomachinery, aeroacoustics, two phase flow or something similar. unfortunately the people hiring CFD engineers (and FEA analysts for that matter) are stuck with the mindset that a master's degree is required to simulate flow in a pipe with a commercial CFD code. what ends up happening is that guys get MS/PhD doing advanced research into all sorts of ultra advanced topics and go out into industry doing undergrad work (sometimes). for Jason who posted this message originally i'd have to say that getting the advanced degree may not be worth it especially if you plan to stay with the same company. if you change jobs and work in a field that can utilise the knowledge you gain in grad school then it may be worth it. also you have to weigh the hidden cost of going to grad school. most schools will give you assistantship/fellowships and if you are an american you can get one of the NSF, DoD, DoE type fellowships, so you probably won't have to pay for school but at the same time you give up your 40-50K a year job for a 10 to 15K a year stipend and go back to living like an undergrad again. also while you are doing this you could be moving up in your jo etc. also there is the uncertainty when you finish of will you get a job that can utilise the skills you've learned. i have schoolmates who have MSs in aerospace going to work as analysts for insurance companies because they are pissed off with engineering. the engineering job market is good and i'm confient of finding a decent job next year when i finish but i'm pretty flexible. if you decide to do CFD you'll probably be focusing on the aeronautical industry which is different. as john said the nmber of companies is contuously dwindling and the market is by definition small (how many airliners are bought evey year-a few hundred even when the market is great). boeing and lockheed are the only two major airframe manufacturers out there. the engine business is the same with GE, Pratt and whitney and Allison being only major players in another small market. so you have to be careful about CFD. if you're an american you can go to school for free and get a job anywhere but for those two years you're in school (for a master's, about 6-7 for a MS+PhD) you'll be losing out and the job you get when you come out is not going to pay superbig dollars (ie not 70K+). (3)i think if you want to learn CFD to the point where you can understand what goes on in this forum and use commercial codes properly you can go to your nearby university and take a few grad courses in CFD/numerical methods, fluid mechanics and read a lot of texts/ papers in their library.

i wanted to say more but i've gone long enough

Re: Is it worth it?
 

this thread is great. a good discussion on the philosophy and economics of CFD. i'm continuing my previous message. didn't want to put everything in one message it'd be too long. (4)as for commercial codes you have to take the manufacturer's claims with a grain of salt. Dr. Sarkar made the point the the commercial CFD codes must move to the level of maturity of structural FEA codes. structural FEA is at the point where somebody who's taken an intermediate/advanced course in structural analysis/strucutural dynamics can get on and learn to use these codes with only minimal understanding of the finite element method itself. ie you only need to know the difference bewteen element types and which BC to apply and you're good to go (ie read the instructions). i took a grad course in finite elements in undergrad and from that i was able to teach myself to do analyses on ANSYS with repeatable, design quality results. the same is not true for CFD. the physics and the appropriate numerical scheme are closely linked. so taking a few intermediate/advanced course in fluid mechanics/aerodynamics cannot prepare to use even the simplest (say compressible euler) code properly. in fact the lack of true understanding of CFD is shown by some of the questions asked on this forum. these questions indicate that the users (while they understand fluid mechainics) do not have a good grasp of CFD. (5)even CFD courses in grad school may not expose you fully to the subject. for example the CFD courses i've taken have concentrated mostly on high Reynold's number compressible flow (typical in aircraft design-i'm in an aerospace department) so for the most part we concentrated on time iterative schemes. so when someone asks me about a pressure based scheme eg SIMPLE i have little understanding of that. it's just a matter of what you're doing. i'm sure if i had taken a CFD course more geared toward incompressible flow (electronic cooling, process fluids etc) i'd have similar difficulties in understanding the nuances of time iterative schemes (unless the professor was into preconditioning). (6) in the same way you have to be careful about these "general purpose" commercial codes that use one scheme to solve everything. it'll probably turn out that it'll be great for airfoils and turbomachinery but suck (or be less impressive) at incompressible flow. (7)on the other hand commercial codes often have impressive pre- and post- processing features. but if the solver isn't good it's just pretty pictures. (8)if problems are modelled carefully and the analyst understands fluid mechanics and CFD i think that most commercial CFD codes out there can give good results. i've seen impressive results with commercal codes (Fluent, CFDRC, StarCD etc) on relatively complicated problems but these were obtained by good analysts (i'd hate to see some of the trash that poor analysts come up with). it's the user not the code. (9)commercial codes are not necesarily worse than research codes (i mean the solvers) i've ssen good, bad, and indifferent results with research codes see point 8. often many research codes are old, not suitable for modern computer architectures, or just outdated. NASA is still providing old thin layer Navier Stokes codes (not saying TLNS analyses are useless but you have to be careful) and many of their codes are for vector machines when industry is using parallel machines etc. also many sponsoring agencies are not pushing algorithm/code development anymore because they feel they've spent enough money on it. i think it is up to the commercial companies to push algorithm development since they'll make money off it. but i see many commercial codes still using MacCormack schemes or pressure based schemes (from the 60's and 70's) when so many faster, more accurate and widely applicable schemes have come along since 1981 when Jameson unleashed the 4 stage runge-kutta scheme on the CFD community. (10)as an aside i see that in the future europe may take away the US's dominance in CFD code development because the europeans are still developing schemes and putting them in commercial codes while in america the codes contain old schemes and they're more interested in fancy postprocessing. america dominated teh CFD scene because of algorithm/scheme development AND IMPLEMENTATION and computational dominance. as i said above the first no longer seems to be true (especially implementation - new schemes are being developed in the US but not necessarily being widely implemented) and the computational dominance is also disappearing. now that you can string together a few hundred PCs and get the performance of an Origin or an SP2 at a fraction of the cost you no longer need a big supercomputer industry for CFD dominance. i read a webpage where some fellas at a DoE lab set up a 100 odd processor workstation cluster in a weekend. we have at least two such clusters here (penn state) and both are administered part time (and were built) by aerospace grad students (11)lastly. you have to understand that what may be a poor result in certain cases may be adequate in others. ie there is nothing hard and fast as to what constitutes a good CFD result. In structural analysis near perfection is expected butin CFD that's not the case. Case in point i took a visit to Pratt & Whitney last year. they've basically dismantled much of their structural lab because the FEA results are good enough to replace completely much of the testing they used to do. in CFD it's different. P&W has some of the most impressive CFD capabilities in american industry: they have huge computational resources through workstation clusters and have years of advanced, in house CFD code development behind them, they routinely do multistage unsteady turbine and compressor analyses. yet their unsteady CFD results aren't often right on top of the experimental results (ie their exit flow angle distributions aren't perfect or they don't get the secondary flow just right). but they like what they can do with their codes (they're still improving them of course) because otherwise they'd have to test everything out on rotating rigs or full scale engine tests like they did 20 years ago. when you're designing 100K pound thrust engines in ever shrinking design cycles this isn't possible. as their head of code development told us (a guy named Rhie i think) they have to "Just do it" because they have to be able to use these tools to produce their products in their ultra-competitve market. academics can always say "your computed pressure line doesn't lie right over your experimental points" but companies like Pratt are producing better, more efficient products at lower cost every year. sure they'll have failiures, but failiures are less common now than in the past, and nothing is perfect not even experimental results.

that's all i have to say right know. i have a great passon for CFD and all areas of computation because these are the only way we engineers are going to build better products that more people can use in the future. just remember we'll never be perfect but we should try

Re: interesting
 

John, I always enjoy your non-linear thinking. I agree with everything you said. Your last statement just doesn't follow the previous statements??? Anyway, Japanese cars used to be crap. Everyone knew it. They were also cheap. Don't forget to couple price with quality in your market equation. For awhile, the Big 3 made crap cars that were cheap. They were slower than the Japanese to make reasonably priced, high-quality cars. You're absolutely right: The big three didn't improve quality and lost ground because of THE MARKET.

As for moving production to Communist (read: poor, underemployed) countries. Who cares about the motivation? We don't live in a collection of countries with different workforces. We live in a world with artificially segmented salary regions.

For the sake of argument, let's look at it from your isolationist viewpoint. Let's say a guy in Detroit "works" 40 hours per week. He averages an additional 20 hours overtime. Tightening the same 3 nuts over and over again on a Big 3 assembly line, he's likely to bring home $70k+ per year. GM, for instance, has a couple of choices. 1) Set up a manufacturing plant in, say, Tennessee where labor costs are more reasonable. 2) Set up a manufacturing plant in, say, Juarez Mexico where labor costs are CONSIDERABLY less expensive. 3) Close up shop and stop feeding anyone.

You seem to be saying that choice 3 is unacceptable. I agree. I'm guessing you don't like greedy motivations behind choice 3 You seem to think choice 1 isn't so bad because it's keeping jobs in the US.

Get real: there's is no ethical difference between choice 1 and 2. Sure, it's going to have a immediately painful effect on some. Over time, though, it evens out the "disparity of wealth". How's that for a free market making a nod towards one of the supposed goals of Socialism?

Well, we've obviously gone way off topic. Feel free to reply, but I'm done with this thread. Time to get back to what we all love: CFD!

Jeff W

Re: interesting
 

(1). I have just realized that there is no fun in working on CFD. (2). By talking to a human being on Internet, I could see things more clearly. (3). And this is the first time that I check into the web search for the words " non-linear thinking". I didn't know that thinking can be non-linear at all. I had the impression that thinking is always parallel. So, I was wrong. (4). Yes, you are right about what you have said. So, it is hard to change someone's mind in the first place. I agree with you that it is time to move on to other subjects. Who cares about whether it is worth it or not. He probably has already made up his mind long before asking the question. Good night! (or good morning!)

Re: Is it worth it?
 

(1). A real good first-hand report indeed.

Re: Is it worth it?
 

(1). I would strongly recommand that this article be studied in great detail. (2). I do have some comments on it. But in view of the situation, I will just mention a couple of problem areas. (3). Currently, the thermal stress problem in turbomachinery hot sections, combustor, turbines is still a real problem. Ability to run a commercial structure code does not mean that these problems can be or has been easily solved. It is not uncommon for the hardware to crack and melt. (4). The computer hardware has been a driving force behind all the modern computer assisted analysis and design. Its speed will reduce the design cycle time. But it can also produce garbage at much faster speed. Garbage-in-and-garbage-out will only overload the system. So, the speed along will not solve the problem. (5). I have been getting relatively reasonable flow separation and secondary flow results in turbomachinery flows. I don't think you need to use super-computer to get good results. But it is essential that one does understand the physics of the flow, the turbulence models, and the mesh. I don't think running more cases, or using parallel computers will solve the problem. (6). I would like to repeat what I said before, " if you know how to solve a problem, then the problem is nearly solved, so there is no real need to actually solve it". ( do you have to check out the calculator for all the mathematical operation? No! because you know it can be done.) (7). P&W is merging its two divisions. I think, in CFD areas, it is important to seek good engineers from outside the company. Like many large organizations, the key problem is always with human beings. This is especially true for CFD. CFD is neither a code nor a computer. Without experienced, well trained CFD engineers, nothing will be done, and nothing will be solved.

Re: Is it worth it?
 

thanks for your comments john. this is what i wanted sometimes we don't get good discussion on these topics. in response to your point (3) i would say that these structural problem areas (turbomachine hot sections - combustor, HP turbine) are areas where heat transfer analysis is critical. indeed if you think about it the structural analysis is only as good as the fluid dynamics calculations which produce the thermal boundary conditions. in my experience the ability of cfd codes to produce this thermal information is (woefully) inadequate. one of the reasons (personal opinion) is the difficulty in obatining experimental comparisons to validate cfd heat trans results. i've read many papers where cfd code developers validate there codes using surface pressure distributions alone. but in my opinion this only really shows that the inviscid part of your code is working well (ie you have a good euler code) it doesn't tell you much about whether you are predicting viscous features ( which affect heat trans) well. i agree much work is to be done here but i think it is on the cfd side not the fea side. moreover (as i said before) commercial fea code developers are producing good products whereas the same isn't true (in general)for commercial cfd code developers. so in short i agree with you that many new (and even older) engines have hot section structural problems but i think it is more a deficiency on the part of the fluid analysis than on the structural analysis. as to your points (4) and (7) i think you're reiterating what i said and i agree that the results can only be as good as the analyst. aside from that i chose the example of P&W because i'd been there and so i have been told directly by the people there what their issues are. i agree that a large parallel (or distributed) computer isn't needed to get good results but my understanding was that in their case to obtain results fast enough to fit into their compressed design cycle they needed this kind of performance. also i wanted to stress that unlike a monolithic super computer ( say a big sgi or SP2) this computational power comes at low cost since they're just linking the (sun in their case) workstations that everybody already has on their desks. also i used them as an example because they were a case of a company that is in market where cfd is essential to faster design cycles and better products, and that P&W (along with the other big engine companies) have been using these tools to produce better engineered products (faster). i've also read papers written by people in the airframe market who are not as high on cfd because for them the windtunnel is still more cost effective and reliable than cfd so cfd is not as dominant a tool in their case. it's a matter of perspective and the nature of your business the sircraft guys can get their results quickly and acurately via experiment and so they still rely on it (nothing's wrong with that) but for turbomachinery guys experiments are expensive and time consuming so they'll tolerate the shortcomings of CFD because they have to.

Re: Is it worth it?
 

(1). That was exactly the point I was trying to make, the efficiency, the reliability, the life of an engine depends only on one thing, that is CFD. (2). So, an engine company without a strong group of CFD researchers and programs will fail sooner or later. ( I can only guess that when there is a failure in structure, the structure group gets more support to do more work. And no one in aero/thermal would say it's their problem.) (3). About the cost, I can tell you that the current implementation of CFD and the design process in most companies are highly in-efficient. It has become a huge dianosaur. That is a much bigger issue which is going to take a lot of discussions separately. The current form of CFD and CFD codes are highly in-efficient.

Re: Is it worth it?
 

Getting a bit off-topic here, but anyway...

Predicting hot-section life in turbomachinery only using CFD/FEA is far off what we can do today. I've spent 4 years doing research on turbine blade-heat transfer simulations and the current state of the art still has problems to predict heat-transfer in a single linear cascade with homogenous turbulence coming in ... trying to predict heat-transfer in a 3D multi-stage environment is at least two or three classes more difficult, and if you also add combustion things become virtually impossible. The FEA side of life prediction is also often very sensitive to small differences in surface temperatures and a small errors in the CFD prediction can thus lead to large differences in life prediction.

The problem is not that there is no experimental data, the problem is that this is just a d*mn difficult physical phenomena which is very tricky to simulate. Current turbulence models and CPU resources are not able to handle it. To design these sections you have to rely a lot on experience, experiments and ad-hoc models (transition models, turbulence models, correlactoins etc) which were tuned for a similar case. As soon as you want to do something which is different from the typical cases you have to rely on experimental testing to validate your design. One of the most common misstakes I see other CFD engineers do is that they trust their heat-transfer results almost as much as they trust their pressure distributions etc.

You seem to blame these inabilities of CFD on the commercial codes. I can't see the logic - it is not their fault that this is a difficult problem. State-of-the art research codes also have difficulties here. Actually, I've run a few of the test-cases that I worked with for my PhD in one of the larger commercial CFD codes and the results are quite acceptable. Of course you don't get the small fixes and tunes that you have in a research code but results seemed consistant and not that much worse than what I got with my own code.

Re: Is it worth it?
 

(1). I think, readers are very lucky because we have a webmaster who really understand the degree of difficulty in CFD prediction of skin friction and heat transfer. (2). I remember a few years back, I had a discussion with a support engineer about the inconsistent skin friction prediction using their code, he simply said the pressure field is accurate and many users like to use their code. These codes are being used in the real world environment (both in-house and commercial codes) to provide design information for real products. And in some cases, plastic models are used to obtain the needed heat transfer or aerodynamics information. (3). The point I was trying to make is engineers would use any method available to him especially the problem is very difficult. Then, they will run into G_I_G_O problem. (if you have convinced the company to use your code, then it is difficult for you to say that you can't handle the problem. And even if the company accept you statement, there is no other alternative because the code was suppose to replace the testing. Going back to more testing? )

Re: Is it worth it?
 

No.

Get out of engineering. Start your own company that allows direct interaction with the public, e.g. plumbing, TV, AC or PC repair.