# Fluid Structure Interaction

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 August 12, 2005, 06:34 Fluid Structure Interaction #1 pk Guest   Posts: n/a Dear users, I already seen some post about different FSI solutions, I just want which one you should recomend if i have to simulate a problem which invlove a big displacement of my structure (for exemple 20 times a diameter) : which is more best and useful for this knid of problem : between FLUENT + ABAQUS : CFX + ANSYS , FIDAP, STAR CD ?. Thanks for your answer. Pk

 August 12, 2005, 23:17 Re: Fluid Structure Interaction #2 joe Guest   Posts: n/a can you tell me more about the problem you want to solve?

 August 13, 2005, 08:08 Re: Fluid Structure Interaction #3 Mohite S. S. Guest   Posts: n/a Dear Sir, I am trying to model a problem of squeeze film damping for a thin air gap along with loss through hole for a MEMS structure. The geometry is like this, There are two circular discs, one of which is thicker and has a hole in it. The discs are separated by small air gap of few microns, one disc is fixed and the other is oscillating with small amplitude of oscillation in the transverse direction. (The disc diameter is one order of magnitude more than the gap and the hole.) I want to solve this problem using Navier Stokes solver. I have solved it using squeeze film analysis (element 136 and 138 in ANSYS). I am trying to model it as a nozzle problem. The flow is compressible isothermal. Pl advise me in this matter. Thanking you.

 August 13, 2005, 13:13 Re: Fluid Structure Interaction #4 Mani Guest   Posts: n/a Is the motion of the disc prescribed (that's what your description sounds like) or does it depend on the fluid dynamic forces? If it's prescribed, this isn't a fluid-structure coupling problem (i.e. there are no structural equations involved). All you need is an unsteady flow solver with the capability of unsteady wall boundary conditions (prescribed boundary motion).

 August 15, 2005, 04:09 Re: Fluid Structure Interaction #5 pk Guest   Posts: n/a Hi, I fact I want to simulate the behaviour of a net (association of cross element as the basic element) in a flow : So the displacement of the net can be important depending of the flow velocity. I have heard that FIDAP won't be useful for this kind of simulation. What about ANSYS+CFX or FLUENT+ABAQUS?. Thanks for your answer, P

 August 15, 2005, 13:16 Re: Fluid Structure Interaction #6 Peter Attar Guest   Posts: n/a If you have access to your own in-house CFD code you can couple it to ANSYS using the user programmable features of ANSYS..ie you can put subroutine calls to in your CFD go which can retrieve displacements from ANSYS and place pressures/forces on your ANSYS structural model. If you want to do this you should purchase the UPF manuals from ANSYS(they don't come with the distribution). So if you have the time and a CFD code which you can use and don't want to dish out the extra cash for a CFD licence this might be the way to go. I think a similar thing can be done with ABAQUS but I have not personally had any experience in doing it.

 August 15, 2005, 16:24 Re: Fluid Structure Interaction #7 Steve Reuss Guest   Posts: n/a ANSYS and CFX just released version 10.0, which has built in bi-directional FSI capabilities. You need high-end licenses, but if they are available you'll get everything you need from a single vendor.