Hello,

I am running a transient simulation (using ANSYS2020R2) to study the effect of deflector position on the drag force of a tractor-trailer. I have written a UDF with CG_MOTION macro to rotate the deflector up and down which is working fine so far.

My next task is to rotate the deflector lets say, 1 degree (1st-time step) and before moving it to 2 degrees, I want to see the effect of different velocities (e.g 40 to 60mph) at this time step. I also want to see the effect of changing the yaw angle (0,10,20,30 degree etc.) when deflector is at 1 degree. Once all the yaw angles and velocities are solved for the first-time step then I want to change the angle of the deflector to 2 degrees (by changing to the next time step) and perform the same calculations again.

One way of doing is creating a separate project for each yaw angle and run multiple analysis which is a very hectic and time-consuming process.

I was wondering if there is a way to do it with UDF. Take one velocity and run a defined number of iteration to reach convergence then change velocity for the same time step and deflector position, and iterate again. once all velocities are done, change time to the next time step (which will change deflector to 2 degrees) and perform same velocity calculations again.

Any suggestion on how this can be achieved?

Can we actually change velocity at a one-time step and iterate it again and again for different 3 4 velocities and then move to the next time step and repeat same calculations?

I hope my question is making sense to you. I have uploaded a velocity animation where the deflector is moving up and down and inlet velocity is fixed 22m/s for this case.

Thanks