Khamsin Virtual Racecar Challenge 2015

Post here information about your own engineering projects, including but not limited to building your own car or designing a virtual car through CAD.
MadMatt
MadMatt
125
Joined: 08 Jan 2011, 16:04

Re: Khamsin Virtual Racecar Challenge 2015

Post

CAEdevice wrote:with small endplates
Yea that's something to try, I honestly don't know! I am not sure you are going to gain anything, more the opposite as you are going to add drag with your central support (it has to be a 2 support thing to avoid it twisting tho), while with the end plates you sort of keep the flow around the rear of the car more under control. That is unless you want to play with the volume right behind the wheels, which is something I won't have time to consider! :)

User avatar
CAEdevice
48
Joined: 09 Jan 2014, 15:33
Location: Erba, Italy

Re: Khamsin Virtual Racecar Challenge 2015

Post

At the moment I am focused on the front axle area, I will test the central pillar if I have time, but it is difficult. Maybe for the second race.

User avatar
CAEdevice
48
Joined: 09 Jan 2014, 15:33
Location: Erba, Italy

Re: Khamsin Virtual Racecar Challenge 2015

Post

It is not yet time to turn on the light , but the car is ready !

Image

PS: Do not worry JJR , the livery will not be black!

MadMatt
MadMatt
125
Joined: 08 Jan 2011, 16:04

Re: Khamsin Virtual Racecar Challenge 2015

Post

Wow, big change from your first model!

User avatar
CAEdevice
48
Joined: 09 Jan 2014, 15:33
Location: Erba, Italy

Re: Khamsin Virtual Racecar Challenge 2015

Post

MadMatt wrote:Wow, big change from your first model!
The front wing/diffuser did not changed, I added a big flap only for the high downforce races that hides the old shape.
Some changes are in the rear part, as a consequence of the rule changes about cooling outlets.

MadMatt
MadMatt
125
Joined: 08 Jan 2011, 16:04

Re: Khamsin Virtual Racecar Challenge 2015

Post

I see! It looks good, hopefully you find ways to balance the car with rear end downforce! :)

User avatar
CAEdevice
48
Joined: 09 Jan 2014, 15:33
Location: Erba, Italy

Re: Khamsin Virtual Racecar Challenge 2015

Post

MadMatt wrote:I see! It looks good, hopefully you find ways to balance the car with rear end downforce! :)
Yes the balance is good, but the total DF is still too low...

MadMatt
MadMatt
125
Joined: 08 Jan 2011, 16:04

Re: Khamsin Virtual Racecar Challenge 2015

Post

Wow well I am surprised, but that's good news anyway. The CoP position is not that insignificant as it was said in the thread. I ran some tests with the small app and just changed the CoP from the ideal 1.65m and the lap time difference changed more than I expected!

User avatar
CAEdevice
48
Joined: 09 Jan 2014, 15:33
Location: Erba, Italy

Re: Khamsin Virtual Racecar Challenge 2015

Post

My COP is 1,9 without correction (1,75 after the correction), I am quite happy with it. What I 'd need is 150kg more df!

User avatar
variante
135
Joined: 09 Apr 2012, 11:36
Location: Monza

Re: Khamsin Virtual Racecar Challenge 2015

Post

Matteo, from what i can see of your car (almost nothing at all...) you've refined big slices of bodywork compared to your first iteration.
Also, you said that you were going for a similar RW endplates to Matt's, but i think you've shaped them differently so that they prevent the formation of harmful lifting vortices over the rear wheels arches.

Apart from this, all i can say for the moment is that your cars, Matt and Matteo, look good! :)

User avatar
CAEdevice
48
Joined: 09 Jan 2014, 15:33
Location: Erba, Italy

Re: Khamsin Virtual Racecar Challenge 2015

Post

With the df setup my car is ugly! I don't like very much extreme df tracks :)

julien.decharentenay
julien.decharentenay
10
Joined: 02 Jun 2012, 12:31

Re: Khamsin Virtual Racecar Challenge 2015

Post

Thanks for the pictures. I am uploading them on the banner.

I made a small update to OCCFD to add the weighting of the CoP (it is average of the predicted COP and the optimum COP) as part of the OCCFD output. I also did a minor update for when running AWS simulations... This update should not affect any other items. Updated OCCFD is available at http://www.khamsinvirtualracecarchallen ... edirects=0.

CAEdevice and MadMatt mentioned difficulties in running OCCFD. When working with CAEdevice, it usually helped to "clean" the mesh using netfabb. One of the symptom is that the inside of the car is being meshed - which should not happen. I am not 100% sure, but it also looks like the Windows port of openFoam may not be as robust as the AWS one.

On this subject, the mesh cleaning step has become a bit impractical with the separate intake and exhausts surfaces as I have to close the mesh with the surfaces and then remove the surfaces (pseudo manually). Please make sure that the edges of the intake/exhaust surfaces are matching with the body reasonably well, otherwise there may be some spurious faces (I can't do much about them)...

I am also confirming that you will receive a copy of the CFD results - same as last year. It won't be as streamlined as it was...

The submission portal has been included on the website http://www.khamsinvirtualracecarchallen ... lenge-2015. You should have received an email with your username and key. Feel free to try to submit a file if you want to check and get familiar with the process.

User avatar
CAEdevice
48
Joined: 09 Jan 2014, 15:33
Location: Erba, Italy

Re: Khamsin Virtual Racecar Challenge 2015

Post

Thank you Julien, I think I'll be back to OCCFD for the next race, locally trying with netfab, but maybe with amazon too.

MadMatt
MadMatt
125
Joined: 08 Jan 2011, 16:04

Re: Khamsin Virtual Racecar Challenge 2015

Post

variante wrote:Matteo, from what i can see of your car (almost nothing at all...) you've refined big slices of bodywork compared to your first iteration.
Also, you said that you were going for a similar RW endplates to Matt's, but i think you've shaped them differently so that they prevent the formation of harmful lifting vortices over the rear wheels arches.

Apart from this, all i can say for the moment is that your cars, Matt and Matteo, look good! :)
Thanks variante, yours look mega, very refined, I am looking forward to what it can achieve!

On my side of things, I was able to run a couple simulations on old models just to compare with Star-CCM+ and wow some results are very different. I optimized my car through Star-CCM+ and now I am seeing that solutions I put on the side give better results with OCCFD. Not good for me!

I will then investigate how things are done through Paraview and see if I can improve my car here, now that it is legal. Again I will have some time this Sunday, so I hope I can make it count!

What is your frontal area guys btw? I wonder if mine is not too high, at 1.75m^2.

User avatar
CAEdevice
48
Joined: 09 Jan 2014, 15:33
Location: Erba, Italy

Re: Khamsin Virtual Racecar Challenge 2015

Post

MadMatt wrote:
variante wrote:What is your frontal area guys btw? I wonder if mine is not too high, at 1.75m^2.
At the moment the forntal area of my car is 1,72m^2