[MVRC] Mantium Virtual Racecar Challenge 2016

[rjsa]

Oh Oh.



EDIT: Ok, a tweak on the front splitter got it a bit better, but it's still not converging. What should I look for to fix non converging solutions?

[LVDH]

Hi, sorry for the late reply, I was busy eating a lot the last days.
What you have there looks strange. The top image could be a simulation that totally blew up and the p tot iso surface is simply from the initial field.
The lower one does not look bad. Why do you think the solution did not converge? If you are sure you should probably have a look at your CAD. Is the closed surfaces check utility happy with your stl files?

[rjsa]

It was fixed with a minor tweak, thickening the splitter solved it for good.

While we are at it, I asked you on the private forum if you could publish a statically compiled version of MFlow for linux as you have for windows. Is that possible?

[LVDH]

I will see what I can do and keep you up date date on the support Forum.
You seem to be very busy making sure to be the best prepared guy next year.
Just keep in mind that some rules and the CFD setup will change.

[rjsa]

Ok, I'm having a blast doing it.

Going form 2.5 to 3.2 efficiency was fun. There's a lot to get out of it yet. Now I'm having a hard time going from 2m3/s to the needed 3m3/s.

Are you going to publish the CD/CL numbers for LM?

Or would any of the top guys be so kind and let us know how far from them we really are?

[CAEdevice]

Look at the end of the page:

http://mantiumchallenge.com/mvrc-calender-results/

[rjsa]

oh it's there now, tks!

[Ft5fTL]

This question is probably stupid but here goes; i will add my car to rfactor 2 but im wondering, is the Cl*A values = newton values? If not how can i convert them to newton?

[CAEdevice]

DF = 0.5 * rho * (Cd*A) * v^2

Usually driving simulators require to fill in a table with DF and v or simply compute it assuming Cd*A constant.

In the old KVRC Cd*A was computed at different speeds, but the difference were negligible.

[LVDH]

Yeah the physical unit of Ci*A is m². To get to a force you have to use the formula Matteo showed. The force depends on the velocity. In this case we assume that Ci or Ci*A is constant and does not depend on v. Well, this is an assumption you often find when dealing with cars. In real life Ci does depend on v, but in most cases it does not matter as the dependence is for one complicated and it actually does not change very much. As Matteo pointed out, when KVRC did use different velocities it did not affect the results much,

If you manage to get you car into rFactor, please make sure to show it to us all. We are all waiting, good luck.

[Ft5fTL]

So if my calculations are correct (probably not) my car at Le Mans produces 0.985 N drag @160 km/h. And if the formula is the same for downforce the car produces -4.834 N lift @160 km/h.

[CAEdevice]

Nm?

[LVDH]

A good way to check you math is to keep track of your physical units. If you end up with Nm for a force something went wrong.

[Ft5fTL]

That is Newton not Newton metre. It was a late night post .

[Alonso Fan]

That is Newton not Newton metre. It was a late night post .

I get around 1032 N for your drag force and around -5037 N for your lift.

Seems about right to me, good job