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Ben Metodiev May 17, 2001 22:11

The cost of CFD efficiency
Hi CFD Users,

I would like to know your opinion on the cost of the CFD efficiency for Industry. By using CFD we need to improve design or technological process. For the purpose we need accurate results when ccounting for the essence of the physics. A few CFD code offer good multiphse/free surface/conjungte - physics which in fact is in the most real processes. The cost of those codes is from US$30K to US$70K and even more. In dditional the Company has to hire an experience CFD specialist and pay him at US$ 50K-80K and buy high-tech PCs of at least US$10K. The total cost per year can go beyound US$150-200K.

Does CFD justifies its cost? Should we look for a general purpose expecive CFD software as those of Fluent, Star-CD, CFX and others or better find much cheaper software which hs the cpabilities we need. Where to look for such software? -especilly if we work for Industry outside USA?

Thank you very much for your attention, Ben Metodiev CFD Aided Design

John C. Chien May 18, 2001 05:32

Re: The cost of CFD efficiency
(1). It all depends on your business and products. (2). For the next generation military aircraft project, the answer is : the cost of CFD is very small. But the production cost is very high. (3). If the product is a small water pump, then it is obvious that the CFD cost is not cheap. (unless the order of the pump is high volume ) (4). The other area is the military jet engine business. (5). In general, for commercial product business, you are trying to reduce the cost. So, CFD type of analysis is likely to be eliminated. (unless you are facing tough competition and must use CFD to create a new product with high performance to win the contract.) (6). Well, Because of the long time involved in doing CFD, unless it is optimized in industrial environment, the pressure on CFD engineer will be very high, trying to meet the deadline. (7). In any case, there are industries and products which require the use of CFD. Once the product is designed, then it is hard to say whether CFD is still needed.

John C. Chien May 18, 2001 17:37

Re: The cost of CFD efficiency
(1). To do CFD is not really difficult at all. But if you are thinking in terms of codes, then you are not going to get the right answer, unless you are the expert yourself. (2). CFD is nothing but numerical analysis in fluid mechanics. And most published information should be more than enough to solve the average problems. (3). I have been answering CFD question here for nearly three years now. And I wrote my 3-D Navier_Stokes code in less than two years, 28 years ago when working on my PhD. (4). So, in the open literature, you should be able to find more than enough material to write a code specific to your need in one year. (you don't have to write a fancy general mesh generation code, or post-processing code. (5). As a matter of fact, most industries still use their own specialized code to do their analysis. For the companies using commercial CFD codes, they are expert consultants. For me, I would use commercial codes in consulting work. But for highly efficient solution, I would write my own code to handle mesh, solver and graphics. (6). For a new comer, a general commercial cfd code is almost useless...A Sweet Candy for Kids.

Jim Park May 21, 2001 10:24

Re: The cost of CFD efficiency
Seems to me that $50-$80 (US) is a bargain. When the cost of benefits (health insurance, vacation, professional development) and the overhead (part of a secretary, computer and support costs, office space, telephone, FAX, internet access, etc) is included, I would expect $100-$200 US per hour. Salary is only a part of the package.

Dr Strangelove May 21, 2001 16:36

Re: The cost of CFD efficiency

I think John Chien summarizes many good points for you to consider before making a decision.

You need to answer some questions for yourself:
  1. What really is the problem I'm having with my process?
  2. If it is a problem for which CFD is an appropriate tool, then how much time and money would I be willing to budget to have it solved?
The usual answer to the second question is that "I need the answer yesterday" and "I'd rather it cost next to nothing." Those are the quick, easy answers that you need to move beyond.

In any event, whether you:
  • go with a consultant (O(weeks)),
  • purchase a license for a commercial CFD code and hire someone that can run it (O(months)), or, in the most extreme case,
  • hire someone to write a custom code for you, which they run for your special application (O(years))
be sure to get someone that understands the physics and the fundamentals of the numerical methods.

If you don't take the time and energy to sift out a quality person to do your CFD job, then you'll end up compounding the time and money poured into finding a solution with the added disappointment of getting<blockquote>The right answer...but to the wrong question!</blockquote>at the end of the endeavor.

Good luck.

John C. Chien May 24, 2001 22:27

Re: The cost of CFD ?
(1). The cost of doing CFD analysis is consist of several items, namely, (a). the computer cost, including hardware and the system software, (b). the computer time cost, which is required to obtain the converged solution or the mesh independent solution, (c). the labor cost of the researcher, who must be paid at certain wage of salary level, (d). the software cost, which is used in the analysis by the party other than the researcher himself, (e). the office cost and related cost such as the insurance etc... (2). I don't know how the questions and answers in cfd-forum is calculated in terms of the cost. Apparently if the answer is from the higher cost of living countries, then it will cost more. (3). And if we ship the software development to the lower cost of living countries, then the cost will be lower. And it looks like that the computing time will also be cheaper in addition to the cost of the researcher. (4). So, from this point of view, CFD analysis is ideal for the low cost of living countries. Then when the converged solution is obtained in the low cost of living countries, it can then be packaged as software and sell it to the high cost of living countries to make a profit (a lot). (5). On the other hand, if the process is reversed, then it is not going to work. The software code (which is not yet the converged solution) packaged in the high cost of living countries will cost a fortune in the low cost of living countries, thus make the cfd work not practical. (6). So, my question is: what is the true value of knowledge? The Internet makes it possible to exchange the information without the calculation of the cost. But apparently, in terms of the daily cost, the cost (or value) of cfd-forum answers are not equal. (7). I think, I am touching a deeper issue here. Without some kind of compensation, this kind of exchange seems to have limit. Apparently, the person in the higher cost of living countries will have to donate more and work harder. (8). So, the software cost is just the tip of the iceberg. And I think, with the Internet, this will change the equation as how we calculate the cost (or value) when exchanging ideas. (9). I think, time is universal. And if the cost of software developed in higher cost of living countries must be used in the lower cost of living countries, then the converged solution should also be calculated at the high cost of living level. (10). I think, this is an interesting issues, because I have heard that some software are being outsourced to lower cost of living countries. (how do we eveluate the quality? the reliability? in the same way? who's standard?) (11). The question I have is: How do you evaluate the final cost of cfd solution? If there is no standard formula, then how do you interpret the values of the cfd-forum questions and answers?

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