A simple question about time step with wind turbine simulation

Joao Bomfim · October 17, 2019, 19:59

Hy ladies and gentlemen,
I have simulated a VAWT with sliding mesh Technic, constant free stream wind velocity and, to change TSR, the angular velocity is modified. My question is:
When I change angular velocity I should to maintain time step value or I should fix the angular step (Delta theta) for the others TSRs points? Have a great day!

Carlo_P · October 18, 2019, 03:52

In theory, you have to change the time step,
As always, if you can use a smaller time step would be better.

Can you have an idea of your Courant Number?
It would be better to have it smaller then 20-50. It depends of the solver.

Cheers!

Joao Bomfim · October 18, 2019, 09:56

Quote:

Originally Posted by Carlo_P

In theory, you have to change the time step,
As always, if you can use a smaller time step would be better.

Can you have an idea of your Courant Number?
It would be better to have it smaller then 20-50. It depends of the solver.

Cheers!

Hy Carlo, thanks for you answer. My higher Courant number is about 250, but I previously did a time step study for the one TSR point, and this give me a time step equal to 6e-04 s, equivalent to 2 degree per times step. A value under this don't show a significant difference. So, I did this thread to know if should I use 2 degree per time step or use 6e-04 s per time step. Grateful for your attention!!!

October 17, 2019, 19:59	A simple question about time step with wind turbine simulation	#1
Joao Bomfim New Member João de Sousa Bomfim Neto Join Date: Oct 2017 Location: Maranguape, Ceará, Brasil Posts: 27 Rep Power: 9	Hy ladies and gentlemen, I have simulated a VAWT with sliding mesh Technic, constant free stream wind velocity and, to change TSR, the angular velocity is modified. My question is: When I change angular velocity I should to maintain time step value or I should fix the angular step (Delta theta) for the others TSRs points? Have a great day!

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October 18, 2019, 03:52		#2
Carlo_P Senior Member Carlo_P Join Date: May 2019 Location: Italy Posts: 176 Rep Power: 8	In theory, you have to change the time step, As always, if you can use a smaller time step would be better. Can you have an idea of your Courant Number? It would be better to have it smaller then 20-50. It depends of the solver. Cheers!