Learning Forum

[Bewe97]

Hi, I am trying to find a good tutorial on how to make a 3D simulation of an airfoil in cfx. I am not sure how to set up the domains around the foil, but in the end I need to find lift and drag force and pressure distribution on both ends and the middle. Can anybody help me out on this one? I was thinking of making a box around the foil and sliceing it near the surface for a more refind mesh around the foil. I see alot of people making a sphere/sylinder instead of a box. can anybody explain why?

[FaizanYounas]

You can take help from these tutorials. Especially the one name "Wind Turbine Blade". In that tutorial, they have explained about simulating airfoils and 3d turbine blades.

https://confluence.cornell.edu/display/SIMULATION/FLUENT+Learning+Modules

[rfblumen]

Although not an airfoil example, CFX Tutorial 8 (Flow Around a Blunt Body) goes through the setup of simulating flow around an object. This example is applicable to external flow cases.
The thing to keep in mind is to make your domain large enough such that there will be no or minimal interaction between the airfoil and the domain boundaries, but also not making it too large as this will increase the overall node count of the model. The shape of the domain, if the domain boundaries are far enough from the object of interest, shouldn't affect parameters such as lift and drag on the airfoil. The important thing regarding the domain shape is the shape should allow applying proper boundary conditions to the outside of the domain. With a box shape, you could align the box ends with the flow direction and apply a velocity inlet to one end and a static pressure outlet to the other end. The other box sides could be symmetry or free-slip walls. Also, including proper mesh inflation on the airfoil is important.

[Bewe97]

thanks guys, this helped alot