Wow, cool thread! I'm one of the developers of a NASA CFD package (TetrUSS) and do a lot of ground vehicle CFD in my outside consulting work. Here's one of my latest applications:



I would love to do an S2K -- do you have a full CAD model of the geometry? Can I get it? Looks like you're running a simplified or maybe approximate shape now.

To address some of the previous points -- if this is inviscid, then there would be no turbulence and the turbulence model is irrelevant (it's not even used for inviscid analysis). This could be some sort of coupled inviscid/BL method though. If it's fully inviscid, then the solution is probably not realistic due to the large amount of separated flow. You really need full Navier Stokes, and something like detached eddy simulation, to properly tackle ground vehicles with wakes.

At low speeds like this, including compressibility would actually be a liability -- it would slow the solution down unless there is some sort of preconditioning used. So running incompressible is the proper/correct approach for sure.

I have heard a lot of good things about Blue Ridge, in fact one of our developers went to work for them recently. The package is well known for basic-level CFD analysis that is accessible to the CAD/design crowd. That's a huge market, which is not well served by tools like FLUENT or the NASA codes. For aerospace, the NASA codes and in-house company codes (Boeing, Lockheed, etc...) still seem to be the most popular.

Craig

 

Hey, somebody really needs to get him a better CAD model! The website says it supports Autodesk Inventor, CATIA, CoCreate, I-deas NX, Mechanical Desktop, Pro/ENGINEER, SolidWorks, Solid Edge and Unigraphics NX. Surely somebody out there works with one of these and is an S2000 fanatic!

 

Hey, so where's the best location relative to the semi to place an S2000 to get the best drafting effect?

 

Good stuff!

What drag coefficients result from your model? I may be pulling numbers out of my ass, but for some reason I seem to recall seeing reports of 0.36/0.41 for top up/top down configs of the car. Does that jive reasonably well with your CFD results? Might be a rough indicator for the accuracy of your results...

 

That's all that managers usually want to see: C(olorful) F(luid) D(ynamics).

 

See? That's why I let the aero guys run the CFD codes. Fifteen years of doing acoustics and emissions has left me as a customer of CFD, not a supplier. Even though once upon a time I used to be an aero guy myself. Now I just know enough to get into trouble.

 

Wow, this is really cool (though somewhat over my head). I've always been curious if there's a huge difference between top down/windows down and top down/windows up. I would think the windows are quite effective at keeping the air moving down the sides rather than getting sucked back in behind the windshield. The cabin certainly feels less turbulent from the driver's seat...

Peter

 

Inside the trailer.

 

As close as you can get to the back bumper without getting underneath

(inside the trailer would be good too)

But hey, if we had a good CAD model of the S2K, I could run a case with it behind the truck!

Craig

 

I posted the paper model suggestion. The thought of a paper model sitting in a wind tunnel is actually kinda funny. I merely suggested that he have a 3D model sitting on his monitor while he was modeling the vehicle in his CAD.

I'm a visual learner. I need to touch/feel stuff to fully understand the details. Doing that paper model made me appreciate the graceful lines of the car. Thought that might help a bit.