[MVRC] Mantium Virtual Racecar Challenge 2016

Post here information about your own engineering projects, including but not limited to building your own car or designing a virtual car through CAD.
rjsa
51
Joined: 02 Mar 2007, 03:01

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

Oh Oh.

Image

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?

Image

User avatar
LVDH
44
Joined: 31 Mar 2015, 14:23

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

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
51
Joined: 02 Mar 2007, 03:01

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

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?

User avatar
LVDH
44
Joined: 31 Mar 2015, 14:23

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

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
51
Joined: 02 Mar 2007, 03:01

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

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?


rjsa
51
Joined: 02 Mar 2007, 03:01

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

oh it's there now, tks!

User avatar
Ft5fTL
20
Joined: 28 Mar 2013, 05:27
Location: Izmir
Contact:

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

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?
Mantium Challenge - Pure Power Racing

User avatar
CAEdevice
45
Joined: 09 Jan 2014, 15:33
Location: Erba, Italy
Contact:

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

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.

User avatar
LVDH
44
Joined: 31 Mar 2015, 14:23

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

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.

User avatar
Ft5fTL
20
Joined: 28 Mar 2013, 05:27
Location: Izmir
Contact:

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

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.
Last edited by Ft5fTL on 30 Dec 2016, 17:22, edited 1 time in total.
Mantium Challenge - Pure Power Racing

User avatar
CAEdevice
45
Joined: 09 Jan 2014, 15:33
Location: Erba, Italy
Contact:

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

Nm? :shock:

User avatar
LVDH
44
Joined: 31 Mar 2015, 14:23

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

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.

User avatar
Ft5fTL
20
Joined: 28 Mar 2013, 05:27
Location: Izmir
Contact:

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

That is Newton not Newton metre. It was a late night post :) .
Mantium Challenge - Pure Power Racing

User avatar
Alonso Fan
10
Joined: 06 Apr 2013, 18:21

Re: [MVRC] Mantium Virtual Racecar Challenge 2016

Post

Ft5fTL wrote: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
SHR Modding
Youtube
Twitter
Discord

Sound Developer for Reiza Studios
Sound Modder for Assetto Corsa

Post Reply