How do I calculate power coefficient with respect to TSR of savonius VAWT ?

ahmedna8 · November 20, 2019, 12:37

I Am trying to simulate Savonius VAWT WITH HELICAL ROTOR OF 180 through CFD. Problem I am facing is that value of Cp or Ct is always increasing with respect to TSR and not decreasing at any point in whole range of TSR used (0.3-1.2).like experimantal data

For calculation of Cp, I am using following formula.
Cp = Ct* TSR

For unsteady simulation Time step size according to angular velocity of turbine were set for 360 step for a complete revolution of turbine.

Simulation were carried out for 4revolution and Cm- history were stored for each time step. Last 360 time step were used to calculate average Cm (coefficient of moment).
and I used this avg . Cm as Ct (torque coefficient) and calculated Cp. But Value I found for whole range is always increasing.
Pls Suggest me where I am making mistake

HuseyinCan · May 19, 2020, 19:31

Hello bro, i have excatly same problem with you i hope u have solved it? i have changed mesh like 10 times but still same problem i hope you could help me.

danielgem2012 · October 4, 2022, 19:17

please email me if you found a solution.

danielgem2012@gmail.com

November 20, 2019, 12:37	How do I calculate power coefficient with respect to TSR of savonius VAWT ?	#1
ahmedna8 New Member ahmed eissa Join Date: Mar 2019 Posts: 8 Rep Power: 7	I Am trying to simulate Savonius VAWT WITH HELICAL ROTOR OF 180 through CFD. Problem I am facing is that value of Cp or Ct is always increasing with respect to TSR and not decreasing at any point in whole range of TSR used (0.3-1.2).like experimantal data For calculation of Cp, I am using following formula. Cp = Ct* TSR For unsteady simulation Time step size according to angular velocity of turbine were set for 360 step for a complete revolution of turbine. Simulation were carried out for 4revolution and Cm- history were stored for each time step. Last 360 time step were used to calculate average Cm (coefficient of moment). and I used this avg . Cm as Ct (torque coefficient) and calculated Cp. But Value I found for whole range is always increasing. Pls Suggest me where I am making mistake

October 4, 2022, 19:17	Did u find a solution ?	#3
danielgem2012 New Member daniel gemayel Join Date: Sep 2022 Posts: 2 Rep Power: 0	please email me if you found a solution. danielgem2012@gmail.com

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May 19, 2020, 19:31		#2
HuseyinCan New Member Hüseyin Can Sülük Join Date: Apr 2020 Posts: 21 Rep Power: 6	Hello bro, i have excatly same problem with you i hope u have solved it? i have changed mesh like 10 times but still same problem i hope you could help me.