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Gabor BALINT October 10, 1999 10:00

Fluid-Structure Interaction

I want to simulate a cantilever plate vibrating in an incompressible fluid. I use FLUENT code for CFD similation and I-DEAS code for the structure simulation. I iterate between the two codes until the equilibrium state is achievd.

I want to know if there is someone who has similar problem.

Are there any other possibilities for the simulation?

Jonas Larsson October 11, 1999 02:30

Re: Fluid-Structure Interaction
Eh, I'm not sure of how you are doing this. Fluent can not handle moving grids today! Doesn't the "vibrating plate" require that you move the grid around the plate in the CFD simulation? I think that there are other commercial codes which can do this (STAR-CD perhaps, have no own experience from it).

Gabor BALINT October 11, 1999 04:24

Re: Fluid-Structure Interaction
The procedure what I have to do now is the following:

I save my mesh and the pressure on the plate under the format universal (*.unv) and I read this in I-DEAS. After doing this, I-DEAS simulates the deformation of the plate and I take it back to FLUENT.

Of course I had some problems with the compatibility of the universal file writen by FLUENT and I-DEAS code but after all I could solve this with my own C program code.

Regarding the deformation of the mesh around the plate, I'm out to generate a coarse mesh for the first time and to refine after the deformation acheived.

Could you tell me more how can I have more information about the STAR-CD?

Anyway, I know that the last version of FIDAP (8.5) have the capability to simulate some fluid-structure interaction but the approach is still static. I mean that it doesn't work for high vibrating frequency so no possibility to study the phase shift between the fluid and the structure. (Just like in the case of coupling the two codes FLUENT and I-DEAS)

Jonas Larsson October 11, 1999 07:04

Re: Fluid-Structure Interaction
Ah, ok, you assume that the response time of the flow is much faster than the repsonse time of the structure so that you can compute the steady flow for each structural deformation. I don't know if STAR-CD can solve the structure also, I suspect not. I think, however, that it can handle moving meshes. You can probably get more info by contacting them. Their web site is at The next version of fluent (version 6) will also have this moving mesh capability, but it wont be released until late 2000.

You metioned that you only want to have a refined mesh after the deformation - sounds strange if this is a vibrating plate which continually deforms back and forth. Perhaps I've missunderstood the whole case :-/

Raza Mirza October 11, 1999 10:41

Re: Fluid-Structure Interaction
CFD-ACE+ from CFD Research Coporation offers a module to carry out coupled Fluid-Structure Interaction simulations. It has been used for more than year now by our customers, and by engineers at CFDRC, to simulate problems involving fluid-structure interaction.

Visit our website, Look under Software Products-->Addons-->CFD-FEMSTRESS. You will see many neat examples of simulations with couple Fluid-Structure Interaction. For more information, please write to

Gabor BALINT October 12, 1999 04:54

Re: Fluid-Structure Interaction
Yes, so I mean that I dont wan't to deform all mesh around my plate, rather I use the refining mesh capability of the FLUENT. So first I create a coarse mesh with P-CUBE around the plate and only in FLUENT I'm going to refine automatically and doing so I have possibility to add or to delete nodes near my structure. (to avoid the error message: non positive volume exist)

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