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Nasim Suleman July 21, 2000 15:21

Evaluation for CFD software purchase
I am evaluating CFD softwares that we are going to purchase for the company to use for our product design and analysis.Our scope of works are posted on our web site or under energy system for sofec.

Suggestions or feedbacks in this regard from the users are also appreciated.

Thanks and regards.

Nasim Suleman

John C. Chien July 22, 2000 11:17

Re: Evaluation for CFD software purchase,a recipe
(1). You are wasting your time. (2). Pretending that your company owns all of these commercial cfd codes and all of these codes are currently available on their cmputers, there is still a very long way to the improved product design and analysis. (3). Design and analysis are performed by engineers, the purchase of software are "not" going to change that picture. (4). The right approach to do is to create a "cfd department" first. Find some engineers to develop some codes for design and analysis.(this is a crucial step. and it is the sign whether a company is going to die or not. to survive, one needs to have at least grandma's recipe.) If that turns out to be a good idea, then try some commercial cfd codes to supplement the in-house codes the engineers have developed. This is the 1-2-3 step to use cfd approach in product design and analysis. It is possible that you are already doing it.(5). So, ask yourself a question: if these vendors of software are now part of your comapny, and these software are all working on their computers, how are "you" going to improve your product design and analysis? (6). When a company is actually receiving the benefit of using cfd in the design and analysis, the company is not going to let you know which codes they are using and how. (7). The cfd code does not improve the product design and analysis. Because these codes are not designed to do such tasks at all. They can only simulate flow field by solving some equations. (8). From the simulation of the flow field to the improved product design and analysis, there is not a sure connection at all. (9). My suggestion is: buy the commercial code one by one, or all at once. (this depends on your needs and the size of your cfd department) train the engineers how to use these codes correctly. give the engineers six months to one year to get familiar with these codes. then find out "a way to improve the product design and analysis". (to link the flow field information to the improved product desin and analysis is itself an unknown art.) (10). By the way, recently I was asked to look at the flow field of a desing using cfd, because over the years no one was interested in it. Presumely, the design was approved by everybody and signed by everybody. My cfd result was consistent with my intuition before the simulation, and it was pretty bad. The 50% of the flow field is heading for flow separation. So, the impact of cfd simulation in this case does not improve the design and analysis. It actually make the design worse. (well, it was not designed in the first place. So, we are back to square one, to start the design process, concepts study, wireframe and wax models, CAD cartoons,etc....then run the cfd simulation again. The fact is, if the customers are not complaining, there is no need to create new design activities. and if someone is worrying about it, then it is a good idea to do it right from the begining. Easy to say, but hard to do, I guess. But the story I just mentioned is real.)

Nasim Suleman July 24, 2000 09:49

Re: Evaluation for CFD software purchase,a recipe
John, I really appreciate your response and all questions that you have raised. Each and every question is reasonable to me but I got a feeling that you donot see the broad picture that I from here.

1- I am evaluating to purchase CFD software. It may be commerical or raw academic or both at the same time.

2- We do have R&D engineers more then 15-16 years experience and software before used in real projects are first trailed with some finished projects and matched with all design guidelines and standard codes in use.

3- I am also going to start developing CFD codes suitable for our product as I will go along with product design and development.

4- Clients requirements to use CFD analysis in certain areas which have simulation effect not major product development and design.

5- I have been cfd-online user and read your almost all comments during two and a half years when I was a graduate research assistant in CFD Institue and was persuing my masters major in CFD. so I knew that you are going to ask that.

I think this answers all your questions otherwise if you have any point or advice please do write here cuz I do beleive in meaningful discussions especially pepole like you.


John C. Chien July 24, 2000 11:15

Re: Evaluation for CFD software purchase,a recipe
(1). If you are evaluating software, you should be running the code already. So, you can evaluate the results to see whether it is good enough or not. If the cfd results are 20% off the test data, you will have to say whether it is still good enough to help improving the product. (2).Yes, experienced engineers are essential in this design and analysis loop. (3). I am not saying that in-house code development will always be the cost effective or the successful approach. But, the activities in in-house code development will let the engineers gain the respect and experience in cfd codes. This is the most important part of the in-house code development exercise, especially when they start using the commercial codes or someone else's codes. You have to simulate the fighting before you can really fight. (4). Capability to simulate flow field with cfd will be a very good PR tool. If you don't know what is going on in the flow field, how are you going to convince the client that the product is in optimum condition? (5). I sincerely hope that you are going to carry out your plan all the way through. So, look at the real problem you are going to solve first. Not the cost you are trying to save.

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