CFD analysis v/s Model Tests of hydromechanical structs 2

[flamby]

Can CFD analysis is an alternative to model tests?

The reason I ask such question because one CFD software vendor told us that we can carry out the analysis of fluid dynamics behaviour without going through actual model tests of the dam overflow spillways and gates.

We design the dam, spillways, gates etc. and carry out model tests to ascertain the forces, discharge, submergence, head loss etc. If such programs can be used for 'model test' we can save our time. But I have no knowledge of CFD methods. How good such software are vis-a-vis model tests? Please post your opinion.

 

[mohr]

Hi flame !!
The software will works very well IF you validate first
your model. Fluid are no simple thing but if you work
very carefully specially with meshing (it is the most impor
tant preprocessing part of your analysis) you will have very
good results with money saving.

Also you can read the FEM applied to fluids of Zienkiewickz
and Taylor to have a complet picture of CFD.

Regards

Mohr

 

[vortexman]

flame,

I think CFD can be a useful tool for you, and can save you time, compared to physical testing. As mohr says, validation is required. One good approach is to ask the CFD vendor to demonstrate their product for one of your problems. For a simple enough problem, they may do this for free. At the very least, they should be able to provide some references and/or examples of successful solutions for similar problems. Keep a few things in mind:

1) Not all CFD products are high quality.
2) Not all CFD products are applicable to all problems. For example, your problems probably require the ability to simulate free-surface flows. Not all products do this well. I know that some do.
3) Just as in physical testing, the quality of CFD results depends on the quality of the preparation. For CFD, this means that the computational mesh must be appropriate, and the computational model must be well chosen ( for example, 3D vs. 2D ).

Good luck,

vortexman

 

[flamby]

Thanks guys for the useful info.
Regards.

 

[Miper]

Until you become an expert user of a particular CFD code, which means that you have compared physical models with CFD results on a range of problems and have learned how to model problems correctly in CFD, you cannot rely on CFD to provide accurate results. The vendor who says that a new user doesn't need a physical test is encouraging unprofessional use of his software.