CFD using OpenVSP & VSPAero

[Ceyda Kavak]

I am new to OpenVSP, so your answers would be really helpful!

For CFD analysis, should I use VSPAero, or export the geometry from OpenVSP to use it with Pointwise&Fluent? 

Can VSPAero respresent the volume mesh in a fluid flow, or do you recommend only surface meshing the aircraft in VSPAero and extruding the surface mesh using Pointwise etc?

[Rob McDonald]

Your choice of VSPAERO vs. Fluent or any solver should be based on what kind of analysis you need, what fidelity you need, and what kind of resources you have available.  We don't know any of those things, you'll have to decide that yourself.

VSPAERO is a potential flow code with two modes - thin surface (like a VLM) and thick surface (like a panel code).  Its primary weakness is it is an inviscid method with only simple models for viscous drag and stall.  It is also not suitable for transonic flow - though it has some capability for subsonic compressible and supersonic flow.

VSPAERO uses some simple techniques to generate its computational 'mesh'.  Those are probably not suitable for use with Fluent.

VSPAERO can calculate velocities and pressures on a cutting plane throughout the volume -- this allows some visualization of the flow around the vehicle.  It also has an ability to survey specified points for the velocity.  VSPAERO does not need or use a volume mesh.

OpenVSP also has a CFDMesh capability which can be used to generate good quality surface meshes with isotropic triangles (no stretching).  OpenVSP has no volume meshing capability.

Meshes without stretching are best for inviscid CFD calculations.  If you need to run Navier Stokes, then you certainly would prefer a stretched mesh.

If you are using Pointwise, you can export the OpenVSP geometry via the STEP/IGES files -- either unintersected or as a trimmed watertight BREP.

You can also export many of our other file formats to Pointwise, depending on what you want to do.

Rob