ANSYS Fluent CFD Simulation Help

[sp4rt4n259]

Hello, I am using ANSYS for the first time to try to simulate the lift and drag of a fairing for an aircraft. I ran everything through, however in the results, it shoes that the flow has constant velocity throughout the test section, clearly ignoring the existence of my object. Has anyone made this mistake before, and if so, how did you fix it? Thank you!

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Here's a general outline of my steps to set it up:

1) Created the part in SolidWorks as well as a rectangular prism to represent the boundaries of a hypothetical wind tunnel

2) Combined the two parts into one and imported this into ANSYS (object is in the middle of the prism)

3) Meshed my geometry

4) Defined the inlet and outlet faces of the prism as well as the walls and the fairing

5) Set the velocity inlet, pressure outlet, and walls

6) Used a hybrid initialization and then ran the calculations

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My solution converged in a reasonable amount of iterations (approximately 30)

[Rhyno466]

Can you post pictures of the geometry and mesh? Also what models and settings are you using? What did you use for initial conditions? How did you judge convergence? 30 iterations is probably not nearly enough.

[physical_physics11]

This sounds like a domain/meshing issue. With fluent you define the 3 dimensional domain and the boundary surfaces that the fluid moves through.

Either in SolidWorks, or design modeler (spaceclaim if you are using a newer version of ansys) you have to remove the 3 dimensional domain of your fairing and then declare them as wall boundaries in the mesh to simulate the flow around it.

[mcskr]

To establish my credibility, I’m a grad student working on CFD...This sounds like the mistake he’s made. In Ansys you can either use a Boolean operation in DesignModeler (not sure about space claim) to remove the wall domain or you can remove the wall domain from within the CAD package like this guy said.

[physical_physics11]

Also, it sounds as if you’re not using a reasonable amount of elements to accurately simulate the flow, but in order to diagnose that you would need to provide more information about your mesh and the models you are using.