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Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 19 Oct 2017, 09:14
by LVDH
CAEdevice wrote: ↑18 Oct 2017, 18:28
Thank you LDVH.
This is the release is going to be used for the next race?
That was my plan. As long as nobody discovers a bad issue why not?
Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 19 Oct 2017, 10:33
by CAEdevice
LVDH wrote: ↑19 Oct 2017, 09:14
CAEdevice wrote: ↑18 Oct 2017, 18:28
Thank you LDVH.
This is the release is going to be used for the next race?
That was my plan. As long as nobody discovers a bad issue why not?
Hi, the new release works perfectly (I just re run the car of the third race). Results are exactly the same as expected.
The only issue is that most of the post processing images could not be generated (only streamlines and ISO-p).
I am goint to test a version with rotated exchangers today (but I am not sure I will use it for the next race, maybe I will submit the same car I used in Sepang, with only the minor legality issues fixed).
Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 20 Oct 2017, 06:26
by RTak12
Alonso Fan wrote: ↑18 Oct 2017, 18:21
Great news and nice to see this mvrc and the software maturing.
Change of topic: Toro Rosso came to my uni today and did a presentation about internships etc and brought a few car parts etc along for everyone to have a look (and free red bull...!) An interesting thing they mentioned (can't remember if it was a response to a question or not) is that they get a cl/cd ratio of about 3 or 4 on their wings and around the region of 10 on their diffuser
So you guys leading the championship are doing a fine job indeed!
Now I wanna know where he goes to Uni.

Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 20 Oct 2017, 07:23
by CAEdevice
Alonso Fan wrote: ↑18 Oct 2017, 18:21
Great news and nice to see this mvrc and the software maturing.
Change of topic: Toro Rosso came to my uni today and did a presentation about internships etc and brought a few car parts etc along for everyone to have a look (and free red bull...!) An interesting thing they mentioned (can't remember if it was a response to a question or not) is that they get a cl/cd ratio of about 3 or 4 on their wings and around the region of 10 on their diffuser
So you guys leading the championship are doing a fine job indeed!
I hope Toro Rosso has done a better development than me

I did not do any CFD from the latest race, only an analysis of all the previous simulations. I don't know how to improve, but I am not happy at all about the flow under my car and diffuser.
Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 20 Oct 2017, 09:00
by LVDH
CAEdevice wrote: ↑19 Oct 2017, 10:33
The only issue is that most of the post processing images could not be generated (only streamlines and ISO-p).
Can anyone confirm this? I am surprised as nothing changed that should affect this.
Anyways, I checked the rear wing lift to drag ratios of all cars and am very surprised. The top cars vary between 4.2 and 8.3! This is a lot. In my opinion getting a lot of downforce from the rear wing with very good efficiency is quite easy and should be a area where everyone should focus on. So why do some people have wings with such a low efficiency? I guess the rest of the car produces so much rear downforce that the rear wing gets detuned and simple does not loose very much drag in that process.
Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 20 Oct 2017, 09:56
by CAEdevice
LVDH wrote: ↑20 Oct 2017, 09:00
Can anyone confirm this? I am surprised as nothing changed that should affect this.
It happend again running a new simulation. The HTML report could not bee generated and most of the pictures (P,V, ...) are missing.
LVDH wrote: ↑20 Oct 2017, 09:00
Anyways, I checked the rear wing lift to drag ratios of all cars and am very surprised. The top cars vary between 4.2 and 8.3! This is a lot. In my opinion getting a lot of downforce from the rear wing with very good efficiency is quite easy and should be a area where everyone should focus on. So why do some people have wings with such a low efficiency? I guess the rest of the car produces so much rear downforce that the rear wing gets detuned and simple does not loose very much drag in that process.
4.2 is a very low efficiency for the rear wing! I have a df/dr ratio around 7.0 and 7.5 because I decided to lower the rear wing in order to help the air extraction from the cooling outlets, but previously it was around 8.
Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 20 Oct 2017, 10:23
by rjsa
I can't get html report either.
mSurf folders: ['mSurf_HX_R_MON_sp000']
ptot iso file to check: C:\openfoam\Ricardo\IDADOX_2017_SAO\postProcessing\isoSurfaceData\2500\isoSurface_pTot.vtk
Traceback (most recent call last):
File "MFlow_PP_merged.py", line 2513, in <module>
File "MFlow_PP_merged.py", line 322, in TB
ValueError: invalid literal for int() with base 10: '04a'
Failed to execute script MFlow_PP_merged
I've been running v7. Now with v10 I see I have the RW efficiency around 5.2, so there's a lot of work to be done there.
Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 20 Oct 2017, 11:43
by Alonso Fan
RTak12 wrote: ↑20 Oct 2017, 06:26
Alonso Fan wrote: ↑18 Oct 2017, 18:21
Great news and nice to see this mvrc and the software maturing.
Change of topic: Toro Rosso came to my uni today and did a presentation about internships etc and brought a few car parts etc along for everyone to have a look (and free red bull...!) An interesting thing they mentioned (can't remember if it was a response to a question or not) is that they get a cl/cd ratio of about 3 or 4 on their wings and around the region of 10 on their diffuser
So you guys leading the championship are doing a fine job indeed!
Now I wanna know where he goes to Uni.
University of Manchester
Last year, Red Bull themselves came
Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 20 Oct 2017, 21:33
by LVDH
Well, I cannot reproduce or confirm the issue but I repacked the Windows version and uploaded it a while ago. If the issue persits I will have to request a case from one of you guys.
Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 20 Oct 2017, 23:06
by machin
Slightly off-topic... But have you guys seen the VW/Pikes Peak news?
https://www.pistonheads.com/news/ph-ger ... 2018/36942
Perhaps next year we could plan to do a Pikes Peak round ourselves, and coordinate it to match the date of the real race?
Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 21 Oct 2017, 08:22
by CAEdevice
Interesting! There was an article about a Pikes Peak car not so different from our cars on Racecar Engineering one or two months ago.
BTW: RE should dedicate an article to MVRC, among the dozens about Formula Students.
Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 21 Oct 2017, 13:21
by LVDH
Pikes Peak is currently what I am personally interested in the most. My dream is to build a car for that race. If someone from Red Bull is watching this, I have a pretty cool car I want to develop, I am only missing some money...
About the championship, maybe we could come up with a flexible set of rules so we can create cars for all the big races during a year (not in order, just my faulty memory):
We should limit it to 5 races, because this championship is a lot of work as is. The question is more if we can create rules so the cars do not have to be modified too much between open wheel and closed cars.
CAEdevice wrote: ↑21 Oct 2017, 08:22
Interesting! There was an article about a Pikes Peak car not so different from our fars on Racecar Engineering one or two months ago.
BTW: RE should dedicate an article to MVRC, among the dozens about Formula Students.
I absolutely agree.
Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 21 Oct 2017, 14:59
by CAEdevice
@Machin: what about Indinapolis? "Efficiency" or "extreme low df" track?
About the rotating HX rules: I don't agree with the 450mm max height rule
Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 21 Oct 2017, 16:34
by rjsa
Mee too. It should be at least 600, so that we get the same layout as the real LMPx stuff
And so far no luck with the reports on V2017.10.
Re: [MVRC] Mantium Virtual Racecar Challenge 2017
Posted: 21 Oct 2017, 17:14
by CAEdevice
600x600 as maximum dimensions would be ok. The porous media makes the simulation realistic by itself, to many limits derive from the old (KVRC) rulebook and CFD model.
A question for LDVH (I could look into the OF case but I don't have any here at home): is there any mesh refinement or specific cell size control in the volume below the floor?
I ask because if next year we will keep the same (or similar) rulebook (I hope so, since we are far from the best possible performances and completely new rules would be an advantage for the best designer and the best hardware, as it happens in real races), I am pretty sure that the underfloor will make the difference between the top cars.