Help with choosing a viscosity model
 

Hi, I am trying to model a sort of extended foil shape 2D section and I would like to get a second opinion on the setup. The shape is a narrow rectangular section with the leading edge of a NACA foil on the front and the trailing edge on the back.

The flow is moving at 0.5 m/s with no angle of attack and the reynolds number is around 415000. I chose laminar flow for the simulation but I got some results that were unexpected. I think it is either because of vortex induced vibration or I chose the wrong viscosity model.

The mesh has more than 300000 elements and is a C-shaped mesh.

Any comments on this setup and model choice would be appreciated.

Hi,

the best for an airfoil profil in Fluent is to do the geometry as shown in the picture and use a far field fonction on the outside.
You should also think about adding prism layer (3 would be enough) around the airfoil and use a k epsilon realizable with enhanced wall treatment viscosity model

sincerly

Adrien

According to the reynolds number the flow wont be fully turbulent, which is why I close laminar flow. Are you saying it will be turbulent?

Tom

Yes, it will be turbulent because the velocity will increase near the naca profil.
So you should use a k epsilon model (or spalart allmaras if the computing is too slow).

Right, I forgot about that. I will give your suggestion a try then. One question though, what do you mean by a prism layer?

I mean the cells that will enable you to get the boundary layer