# Time step for wind turbine analysis

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 March 23, 2011, 16:30 Time step for wind turbine analysis #1 New Member   Amool A Raina Join Date: May 2010 Posts: 14 Rep Power: 16 Hi all, I am using a unsteady density based implicit solver for simulating the flow around a 50m radius wind turbine blade. The turbine rotates at 14 rpm. I would like to know if there is a specific way by which I could determine the time step size for my simulation. I started off with a low time step size 10^-5 and based on the convergence behavior, I kept increasing the size of the time step to 0.01. how do i know of the most appropriate time step size? Any help would be greatly appreciated! Thanks, aar

March 24, 2011, 00:22
#2
Senior Member

Raashid Baig
Join Date: Mar 2010
Location: Bangalore, India
Posts: 135
Rep Power: 16
Quote:
 Originally Posted by amoolraina Hi all, I am using a unsteady density based implicit solver for simulating the flow around a 50m radius wind turbine blade. The turbine rotates at 14 rpm. I would like to know if there is a specific way by which I could determine the time step size for my simulation. I started off with a low time step size 10^-5 and based on the convergence behavior, I kept increasing the size of the time step to 0.01. how do i know of the most appropriate time step size? Any help would be greatly appreciated! Thanks, aar
Hi Everyone,
I have this doubt too about the automatic timestep (how is it calculated)
and physical time step (how it is calculated) and what is the difference between the physical and auto time scale.
Raashid

March 24, 2011, 09:29
#3
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Join Date: Dec 2009
Posts: 41
Rep Power: 16
Quote:
 Originally Posted by amoolraina Hi all, I am using a unsteady density based implicit solver for simulating the flow around a 50m radius wind turbine blade. The turbine rotates at 14 rpm. I would like to know if there is a specific way by which I could determine the time step size for my simulation. I started off with a low time step size 10^-5 and based on the convergence behavior, I kept increasing the size of the time step to 0.01. how do i know of the most appropriate time step size? Any help would be greatly appreciated! Thanks, aar
You have to give a look at some paper about experimental studies in wind gallery.From these papers you could get info about the Strouhal and from the Strouhal obtain the eddies relase frequency and form that obtain the period (inverse).Then you have to consider a time step about 100 times inferior to that period.

 March 24, 2011, 13:28 #4 New Member   Amool A Raina Join Date: May 2010 Posts: 14 Rep Power: 16 do u have any references for wind turbines?

 March 25, 2011, 02:58 #5 Member   Join Date: Dec 2009 Posts: 41 Rep Power: 16

 Tags 3d wind turbine, time step size