Quote:
Originally Posted by rs10
Sounds like you have some amazing tools at your disposal! Not that I can follow every detail of course, and I’m particularly puzzled about one thing.
I understand you are doing virtual aero modeling/testing using computational fluid dynamics. But you also mentioned putting a pressure plate/sensor under each wheel. You also have access to a windtunnel? Or … ?
Also, the 15 degree test at 160kmph you mentioned sounds like driving 160 with a 40+ kmph sidewind. That’s rather quick, so no wonder you got a left/right bounce! But I wouldn’t worry about experiencing anything like that when cornering at 160, as what is happening in the air should be quite differernt, no? For instance, suppose that on a 160 kmph corner you cross a line on the track perpendicular to your direction of travel. If your car is cornering neutrally, then the air that passes exactly over the center of your car when the front wheels cross the line will also pass exactly over the center of your car when the rear wheels cross it (Well, ignoring how the air might get pushed to the side forwards by the car). That’s quite different from a side wind. (And also rather different from going straight. As the front and rear of the car pass the same line, they will be further to the outside. And as the middle passes it, it will be further to the inside.)
Also, even if what happens in the air were the same as with a side wind, 15 degrees is quite a lot. Suppose it was exactly like a side wind (with I can only imagine happening if you have four wheel steering such that the car stays pointing in the same direction, but it moves 15 degrees to the right or left). The wheels would have to be turned at least 15 degrees for that to happen, so your steering wheel would have to be turned, I don’t know, 240+ degrees? I would definitely worry about that at 160!
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Admire your knowledge; Clearly there are two kind of people. Some that are clueless and need CFD tools to aquire understanding and knowledge, and some cool others who can compute nearly all of this stuff out of the head. Fascinating thread indeed!
No 'physical' wind tunnel here, you asked.
That virtual wind tunnel/CFD data (results) was exported into spreadsheets then called back into a totally separate structural analisys. That cfd data can be re-used for e.g. excitations or forced displacements if you prefer. Post structural analisys is meant at solving mostly displacement, force and strains/stress problems on the car componets.
So... set evironment; gravity, humidity, temp, and you can predict the behaviour of lets say; your suspension's preload/compression, damping, the force generated on any brackets, your mirrors' mouting points... stuff like that. You can also predict response dynamics (modal) such as vibrations onto body panels (accoustics) and some other more adv nonlinear problems eg. elasticity, buckling, laminates/ply; how much is my 5mm thick cheap fiberglass front bumper is bending at 200miles an hour (seriously lol).
All started from a 180km/hrs beaten up air fluid data mapped node-by-nodes onto a Boxster car! My training folder is now at 30+ gigabytes of raw *.dat text files bud
Learning the fun way! Chk back in two years... I'll be the official 986Forum Formula 1 Team Aerodymics - adviser