Hi, I'm a Lailong, PhD student in the subject of Aeroelasticity. My major is nonlinear structural analysis using finite element method. In my research for solving a problem of limit cycle oscillation I should use a nonlinear computational fluid dynamics (CFD) to capture the bifurcations and hysteresis. My question is (in case I can not built up a CFD code recently), can I use any CFD software (after I have a steady state with stability convergence) to estimate the aerodynamic loads for each time step of the global time like a STEADY STATE CASE (which I means here that I will solve the problem not a transient but a steady state for a specific time step with deformed body or deformed the mesh)? By the way, I will use the spring analogy to deform the mesh. I will appreciate your reply. Thank you.

If you want a time accurate solution then you need to solve the unsteady fluid equations. Unless I am misunderstanding what you are trying to do....

Dear sir, What I mean in my mail that can I solve the CFD of my problem as a steady state case which means steady state for each time step for example for dt from 0.1 sec to 0.2 sec. Just like a pseudo-steady problem. I appreciate your reply. Thank you

The problem is unsteady of course. How you solve the equations is up to you. You can introduce psuedo-time to get the system to convergence in a fixed time step, and then advance in time once converged. Luca

Dear Sir, Thanks for all who replied me. I know that my information about CFD not too much because my major is nonlinear dynamic structure but I will appreciate your reply. Please, Mr. Luca can be more details about your reply.