I am new to CFD

Project Support
1

Hello, I would like to get a clear Aerosimulation for my project but I am not sure if I have the correct settings. The main goal for my simulations would be to get correct data on how much Downforce/ Drag is created at certain speed. I would share in the following listing what parameters I choose and will also attach a link to the Results.

-Imported .step and build a external Cube arround it

  • did Boolean subtract with the cube and my Project
  • choose Incompressible and the material Air
  • Boundary condition Velocity Inlet on the front where the air is comming from
  • Pressure Outlet on the opposite site with 0 Pa
  • The other sides of the cube I choose wall and set it to Slip
  • Forces and moments I set the Center of rotation closely to the front middle off the cube/project
  • after the simulation I placed Particle trace in front of it and deactivated trace in both directions.

Are these parameters correct or did I miss something importand?

My next question would be regarding the data from the simulation. Is there a way to print it out or get a prefinished document where all important numbers and forces are listed?

My second question would be if there is a correct way to analyse the data. I can see when how much force is moving that´s clear, but I also have the waves. Is it better to have longer and flatter waves or what is generally saying the correct way to read the data?

My Project: SimScale Login

I know I am asking a lot but nevertheless I would appreciate it if someone with more experience could look over it and correct me.

Thank you and if you have any open questions please don´t hesitate to ask.

Greetings, Tim

2

Hi Timmi,

Thank you for your questions.

Regarding the workflow and parameter setup, I would like to highlight two main points:

First, the fluid domain does not need to be a cube. It is typically defined as a rectangular prism that extends further downstream to properly capture the wake. The domain must be sufficiently large to include all relevant flow effects. In your case, the domain appears too short downstream and slightly too short upstream.

Second, the center of rotation is the point about which moments are calculated. It affects the lever arm and therefore the resulting moment values, but it does not influence the force values. Since your objective is to determine lift and drag, the choice of center of rotation is not critical in this case.

Additionally, I would recommend simplifying the geometry. Your current model includes mounting holes, which are not aerodynamically significant and can be removed to improve mesh quality and overall simulation robustness.

For reference, I suggest taking a look at this tutorial, as it closely aligns with your current setup.

Regarding your second question, there is no direct way to generate a pre-finished document with all relevant forces and values automatically listed.

Lastly, oscillating data is generally not expected in a properly converged simulation. In most cases, such behavior indicates that the solution has not reached stability, and the simulation may be considered diverging.

Bryan

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