# Simulating flow past airfoil with different AOA

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 February 26, 2007, 08:58 Simulating flow past airfoil with different AOA #1 ramin Guest   Posts: n/a Hi, I am now trying to simulate unsteady flow past airfoil with different AOA (angle of attack). I've used gambit to generate the structured grids and successfully simulated the flow at 0deg AOA using fluent. Due to the limitation of the software, it is not possible to generate an airfoil with some other AOA. Hence, I am wondering if it is possible to just change the AOA by changing my initial/boundary conditions ie instead of u=1,v=0 at inlet, u=0.707=v for 45deg AOA. Will there be problems? Or is generating an airfoil at different AOA a more popular approach? Can someone recommend a suitable structured grid generator to do that? Thanks alot

 February 26, 2007, 15:53 Re: Simulating flow past airfoil with different AO #2 Sujith Guest   Posts: n/a For airfoil the boundary condition will be ususally farfield bounday condition. Here you can specify the flow direction according to angle of attack.. There are tutorials available on airfoil simulation at www.studentfluent.com

 February 27, 2007, 04:37 Re: Simulating flow past airfoil with different AO #3 ramin Guest   Posts: n/a It's better to clarify my question Quarkz asked ""I am now trying to simulate flow past airfoil with different AOA (angle of attack). I've used a software called MeshPilot to generate the structured grids and successfully simulated the flow at 0deg AOA using my FVM NS solver. Due to the limitation of the software, it is not possible to generate an airfoil with some other AOA. Hence, I am wondering if it is possible to just change the AOA by changing my initial/boundary conditions ie instead of u=1,v=0 at inlet, u=0.707=v for 45deg AOA. Will there be problems? Or is generating an airfoil at different AOA a more popular approach? Can someone recommend a suitable structured grid generator to do that?" in Mon, 26 Dec 2005 (subject:Simulating flow past airfoil with different AOA) and ag answered "Your approach will work fine assuming your freestream is steady. It's referred to as a Galilean transformation. Just remember that lift and drag coefficients are computed parallel and normal to the freestream flow, and are not the components of the force in the x-y coordinate system (except for aoa=0). If you want to change the angle of your airfoil, why not just rotate the grid? It's a simple transformation and is the approach I follow. Write yourself a simple program to apply the transformation."" Now,I'd like to know if i simulate flow past airfoil with different AOA in incompressible and unsteady case,it's possible to change the AOA by changing my initial/boundary conditions(like example of Quarkz). it's seems from answer ag this approach will work only with steady case.Will there be problems in unsteady case? my inlet BC is velocity inlet and outlet is outflow. Thanks alot

 February 27, 2007, 06:20 Re: Simulating flow past airfoil with different AO #4 HSeldon Guest   Posts: n/a Hi, question... How did you exported the mesh file generated with meshpilot in order to read it with Fluent and/or Gambit? Regarding your problem, I think that you can change the AOA without problems, because MeshPilot generates a parabolic far-field. Just go to the boundary condition panels and change the versors in the direction field.

 April 22, 2015, 13:09 #5 New Member   Anthony McCarthy Join Date: Nov 2014 Location: United Kingdom Posts: 21 Rep Power: 3 Hi Ramin, from what i understand from your question you are asking if it is possible to change the angle of attack of the airfoil with out rotating the geometry and re-meshing? If so , yes use your initial conditions of a velocity inlet to enter the components (x, y) velocities of flow for that given angle of attack.

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