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Ansys Learning Forum › Forums › Discuss Simulation › General Mechanical › Fluid-Structure Interaction (FSI) with small deflection option › Reply To: Fluid-Structure Interaction (FSI) with small deflection option

April 11, 2024 at 11:33 am
Rahul
Ansys Employee

Hello 
Large deflection should usually be set to On.

When set to Off the structural mesh position is not updated during the simulation, so System Coupling loads are applied to the original mesh.

If it is transient consider reducing the time step first for transient cases.

Consider the highest frequency, f, of interest on FEA side, and then dt = 1/20f and Consider what a suitable time-step is for good CFD convergence, or to capture shedding freq. Choose the minimum of the two timesteps.

Also, see if quasi newton stabilization helps. Quasi-Newton Solution Stabilization (ansys.com)