# Test cases for incompressible rotating flow.

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 August 25, 2017, 19:35 Test cases for incompressible rotating flow. #1 Member   Akshay Koodly Join Date: Aug 2017 Location: The Netherlands Posts: 43 Rep Power: 8 Hello, Could anyone suggest some test cases(possibly 2-D) for incompressible rotating flows? I have a couple of 3-D cases and they take too long to compute and I would like to use a simpler case with which I can test the solver as I make changes to the code. Cheers.

 September 2, 2017, 21:37 #2 Super Moderator   Francisco Palacios Join Date: Jan 2013 Location: Long Beach, CA Posts: 404 Rep Power: 15 What kind of application do you have in mind? for 2D... maybe the turbomachinery folder is a good option. Otherwise, maybe you can just take an airfoil grid and apply some rotation to simulate a horizontal wind turbine. like in https://www.youtube.com/watch?v=EM4jeOW_2CI Maybe you can take a look at the example in the harmonic_balance folder Best, Francisco

 September 29, 2017, 11:41 #3 Member   Akshay Koodly Join Date: Aug 2017 Location: The Netherlands Posts: 43 Rep Power: 8 Hi, I am interested in wind turbine simulations and wanted to see if I can run the code for some simple cases first. I ran the turbomachinery cases and tried to use the same free stream definitions for an incompressible flow, but wasn't able to get the same results. For now, I ran a Couette flow case which has an analytical solution but needs rotating wall not rotating reference frame. I will also look at some cases in harmonic balance folder. Thank you for the suggestion. Also, I realize MACH_MOTION is used to non-dimensionalize the rotational velocities, compute forces and other post processing steps(Momentum_forces, Pressure_Forces..) but the gas constant appears to be undefined for incompressible flows(not there in SetNondimensionalization and couldn't find any default value). This makes Omega_ref undefined which blows up the solution immediately. As a temporary fix, I added a new config option Radius_of_Rotation and used the input omega to initialize Omega_ref. It appears to work for some simple cases I ran but I am yet to test if it affects any other part of the code. Cheers. Last edited by akoodlyr; September 29, 2017 at 11:43. Reason: Grammar

 Tags incompressible flow, rotating frame