Slow Transient Solution
 

Hello,

I am doing a 2D transient simulation of an aerofoil passing a cylinder to simulate a wind turbine blade passing a tower using a sliding mesh. At the moment my solution is taking quite a while (over 24 hours).

A problem I am finding is that I have set the maximum iterations per time-step to be 800 and it seems to use up all 800 for nearly every time-step. I was under the impression that after the solution settles down it should only take ~50 iterations. I have set the time step to be the time taken for the mesh to slide the length of the smallest element.

For example I am plotting Cl vs time throughout the solution and I understand that the solution needs to settle (possibly due to limiting it to 800 iterations/time step) but I would assume that after a while.

Any help or advice would be appreciated, I have attached some images of the mesh if that helps.

Hello scoobysimon,
I'm not expert in airfoil (I've never simulated one), but I'd say that usually in transient simulation the number-it/time-step is less important than the time-step value: I never used such a large number of it/time-step (max 20-30).
I suggest trying 20 it/time-step and reducing the time-step checking your time-discretization.

Regards