# Difficulty in calculating angular velocity of Savonius turbine simulation

 Register Blogs Members List Search Today's Posts Mark Forums Read

 May 17, 2012, 06:10 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,702 Rep Power: 143 It is likely the device is accelerating and will take a while to reach equilibrium. Rather than using the rigid body solver I recommend you do a series of steady state (well, frozen rotor actually) simulations at different rotation speeds. A series of frozen rotor simulations are far easier to do than a single rigid body model. This gives you a map of torque produced against rotational speed. At the point the torque equals the load (ie zero net torque) that is the steady state operating point of the device. gaist likes this.

 May 17, 2012, 21:48 #3 New Member   Abdullah Al Faruk Join Date: Apr 2012 Posts: 5 Rep Power: 14 Thank you very much Glenn.

 May 2, 2013, 17:39 #4 New Member   asmita Join Date: Apr 2013 Posts: 12 Rep Power: 13 Hello I want to find out the angular velocity and torque of a turbine in Fluent-Ansys. Is it possible to find out ? My turbine rotates in one direction and its enclosed in a rectangle . THe geometry in drawn using Gambit software

 May 2, 2013, 18:40 #5 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,702 Rep Power: 143 Try the fluent forum. khaled ali likes this.

May 28, 2013, 08:01
#6
Member

Join Date: Mar 2013
Posts: 48
Rep Power: 13
Quote:
 Originally Posted by ghorrocks It is likely the device is accelerating and will take a while to reach equilibrium. Rather than using the rigid body solver I recommend you do a series of steady state (well, frozen rotor actually) simulations at different rotation speeds. A series of frozen rotor simulations are far easier to do than a single rigid body model. This gives you a map of torque produced against rotational speed. At the point the torque equals the load (ie zero net torque) that is the steady state operating point of the device.
hi ghorrock
i had simulated a wind turbine using fluent and now i want to calculate the output power using torque.(report-moment)
but all the amounts which i had calculated using this method is 10 times bigger than real amounts
i don't now what to do.
would you plz help me???

 May 28, 2013, 21:36 #7 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,702 Rep Power: 143 FAQ: http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F And you will get more specific help on Fluent on the Fluent forum.

 December 3, 2013, 16:31 help me #8 New Member   khaled Join Date: Sep 2013 Posts: 6 Rep Power: 12 I want how to make to simulate Savonius wind turbine using the rigid body solver of ANSYS CFD v12.1 with sliding mesh of subdomain. How can I calculate angular velocity of rotor and torque on rotor in CFD or CFX-post? and how to calcute drag coefficient and lift coefficient

 December 3, 2013, 16:51 #9 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,702 Rep Power: 143 Using the rigid body solver for this is not recommended. I explain why in post #2. Use a series of frozen rotor simulations at various speeds instead.

March 16, 2017, 06:35
#10
New Member

mahdi
Join Date: Nov 2015
Posts: 3
Rep Power: 10
Quote:
 Originally Posted by ghorrocks It is likely the device is accelerating and will take a while to reach equilibrium. Rather than using the rigid body solver I recommend you do a series of steady state (well, frozen rotor actually) simulations at different rotation speeds. A series of frozen rotor simulations are far easier to do than a single rigid body model. This gives you a map of torque produced against rotational speed. At the point the torque equals the load (ie zero net torque) that is the steady state operating point of the device.
thanks

 March 16, 2017, 17:38 #11 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,702 Rep Power: 143 The load torque is what it is driving. So the generator or whatever is connected to it. mahdi6788 likes this.

March 17, 2017, 03:36
#12
New Member

mahdi
Join Date: Nov 2015
Posts: 3
Rep Power: 10
Quote:
 Originally Posted by ghorrocks The load torque is what it is driving. So the generator or whatever is connected to it.
Thanks. My case has generator but I don't know it's torque at first. Calculation of Rotating speed of turbine is the purpose of project. Then, one generator selects with this speed. My project is calculation of angular velocity of a free turbine that is located in wind.
please give me a suggestion. thank you very much

 March 17, 2017, 04:10 #13 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,702 Rep Power: 143 The generator will have a performance curve, that is torque versus speed. Likewise the turbine will have a torque versus speed curve. Where these curves intersect (ie they are equal) is the steady state operating point of the system. Design of these systems so the generator is appropriately sized to the turbine is not a trivial issue and may require you to run a range of options to see what runs best. mahdi6788 likes this.

March 17, 2017, 05:05
#14
New Member

mahdi
Join Date: Nov 2015
Posts: 3
Rep Power: 10
Quote:
 Originally Posted by ghorrocks The generator will have a performance curve, that is torque versus speed. Likewise the turbine will have a torque versus speed curve. Where these curves intersect (ie they are equal) is the steady state operating point of the system. Design of these systems so the generator is appropriately sized to the turbine is not a trivial issue and may require you to run a range of options to see what runs best.
Thanks.
Generator is not matter because I have to calculation angular velocity that occur by inlet velocity. If I suppose system doesn't have generator and turbine is free, how can I calculate the angular velocity?

 March 17, 2017, 06:08 #15 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,702 Rep Power: 143 If the turbine is free spinning with nothing connected to it then simply find the speed at which it generates zero torque. That will be the steady state, free spinning speed. mahdi6788 likes this.

 Tags cfx 13, wind turbines