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any comments about EFD v5?

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Old   May 16, 2007, 03:21
Default any comments about EFD v5?
  #1
Stephanie
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has somebody already compared EFDv5 with other cfd codes like StarCD or Fluent? What are the results of the comparison?
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Old   May 28, 2007, 16:16
Default Re: any comments about EFD v5?
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Astrid
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We have done some testing (v4.3..... something) in the past and compared it with Fluent and CFX. It is plug and play and you can get results but but but but

- numerical scheme? It is almost the same as upwind. No secon order scheme which is required for every swirling flow. And which flow is not swirling...... - Turbulence models? Only k-e. Not sufficient. - geometrical models with a lot of detail? Impossible - multiphase? not available - radiation? not available

A lot of drawbacks. I was not positive. Haven't continued the trial....

Astrid
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Old   May 31, 2007, 22:35
Default Re: any comments about EFD v5?
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jieremy
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OK,I am regret to hear that Astrid get such conclusion Actually in EFD.V5,the second-order upwind approximations of fluxes are based on the implicitly treated modified Leonard's QUICK approximations and the Total Variation Diminishing (TVD) method. EFD V5 is suitable for engineering,so I think k-e is ok. And because EFD.V5 is fully embended in Catia V5,so there is no a problem with any detail geometry if you know how to use Catia V5. And Astrid is right that EFD can not handle multiphase. Radiation is ok and it adapts Monte-Caro method which is accurate enough

I like EFD.
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Old   June 3, 2007, 07:02
Default Re: any comments about EFD v5?
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Astrid
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Hi Jieremy,

It is good to hear that EFD has improved. We did some testing and it was not in favour of EFD. I would like to see some comparison with experiments of swirling flow. Is that possible?

k-e is ok for a lot of applications but not for heating of water which actually is a very common application. In water Pr=7 which implies that your thermal boundary is much thinner. To solve this correctly at a heated wall you need a very fine grid at the wall. And then k-e is not vallid anymore, and you will be pretty weird results. Your heat transfercoeficient can be a factor of 4 off. Your apparatus can become a factor of 4 times too small. Other packages have suitable models to solve this complex problem. Does EFD have implemented sophisticated things to overcome this?

I agree that engineers won't mind and that they use the results as they come, but I think they need to know these kind of pitfalls. They should not take the results as they come.

Astrid

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