How to set the inflow velocity in LS-DYNA FSI simulation using ALE method?

- May 30, 2023 at 11:14 pm
  
  Qicheng Zhang
  Subscriber
  
  Dear there,
  I am currently working on the FSI simulation in LS-DYNA using ALE method. I need to simulate the structure in wind tunnel inflow conditions. Currently, I use the ELFORM=11, AET=4 in *SECTION command to define the inflow Part of the air volume. The inflow parameters are defined by the *EOS of the inflow Part of the air. There are mainly two parameters in *EOS related to the inflow energy or pressure conditions, E0 and V0. I don’t know how to relate the constant inflow velocity, such as 6m/s, with the setting in the model.
  Many thanks for your support and help.
- May 31, 2023 at 3:55 pm
  
  Jim Day
  Ansys Employee
  
  The initialization of the ambient fluid state (internal energy and relative volume) in the EOS will create pressure and thus velocity in the ambient material. But to sustain the inflow energy or pressure, you would need to include the keyword *BOUNDARY_AMBIENT_EOS to specify internal energy and relative volume as functions of time. If that's insufficient to achieve the desired velocity profile in the ambient material, consider adding *BOUNDARAY_PRESCRIBED_MOTION for the ambient material's nodes. Be careful to consider whether specifying internal energy, relative volume, and velocity of the same material may result over-specification (conflict of) boundary conditions.