We are doing CFD Analysis of a double cylinder Shock Absorber using Fluent. The fluid property and piston speed are known.Is the pressure build inside the cylinder required as inputs? Can anyone tell what should be the Boundary conditions and Is dynamic meshing required or Sliding mesh will do. HAs anyone done a similar problem.

Thanks in Advance

Shaji Abraham

Is this a gas-filled shock or gas over liquid?

Its gas over oil type shock absorber.the shock absorber is a double barrel type where the inner tube is fully filled with oil and outer has got oil and air. Is dynamic meshing required for this type of simultion as the piston is moving?

My doctorate is the development of a new active damper with variable orifices. The numerical model are formed by two piston interconnected by valve that simulate the variable orifice. I use ANSYS 8.0 to simulate. I use these conditions: Initial pressure inside the system; Displacement and velocity are zero in the walls. On the first piston I impose the structural displacement and on the second piston I put one spring. I use dynamic mesh.

I have some problems with the Bulk Modulus of Oil. If someone work with ANSYS/ FSI with oil could help me. I use FLDATA16,BULK,BETA,1,16e7. I obtain this value by the division of oil Bulk by oil density = 9,58e9 / 822. But with large Bulk the convergence is not obtained. Then I simulate with FLDATA16,BULK,BETA,1e5. How I can resolve this problem ? Thanks.