I am very new into Solidworks Flow Simulation. I want to undergo a flow simulation of my car like a wind tunnel testing in real life. I've done the steps coming from the forum and some other sources but none of them has the answer on how to calculate the Drag Coefficient of the car using the formula. I am new into simulations and I am learning it bit by bit in some point. The attach photo is the formula for the Drag Coefficient, I want to know how to calculate the drag, fluid density, velocity, reference area. I want to explain this in my thesis defense concerning how did I get the Cd of my car using the formula.

I've tried something with global goals, and surface goals but I think I didn't get to where I want it to be.

Hope you guys can help me out step by step into this. I'm going nowhere.

Thanks

Peter,

I finally had a chance to run your model. The first thing I noticed was that it was about 10x as big as you thought it was (30 meters long instead of 3.) This was the reason why the forces were so large. I can only assume there was some unit error involved in exporting or importing the STL files. By the way, most CAE software that I've run into doesn't play well with STL files, I recommend sticking with Parasolid when possible. I'm guessing your created this model in a NURBS type environment, that's not usually what CAE is built around.

I used the scaling feature to shrink the model down to 10% of the original size and got to work.

Once I had the solid geometry in the software, the rest was cake. I used a projected sketch to get the cross-sectional area:

I added a floor with a 50 m/s moving wall boundary condition to simulate a road (since this is a car and not an airplane.) It's important to have this wall with the same velocity as the air, otherwise the simulation will develop a boundary layer that will interfere with the aerodynamics of the vehicle.

Finally I ran a rough simulation that gives reasonable numbers, although I wouldn't rely on these since it's just a quick and dirty first pass.

Good luck!