[MVRC] Mantium Virtual Racecar Challenge 2020 (Grand Prix Cars)

[variante]

Wow this scares me.. you guys are following your changes in great detail and this is amazing!!!
This was something i wanted to aim for this season (better tracking of changes). I like the idea of a sheet for tracking overall results and one for detailed results.

Or that we're taking it too seriously

Nono. It's impossible to keep track of what you're doing if you don't lay down your results. It's like sailing blind hoping to go straight. If you're willing to spend time designing the car, at that point you should definitely keep track of the results.

I like it this way:

[LVDH]

I had the same issue in the race I ran last season too, but in the official results all streamlines were generated as expected, so I don't think it's the surface that is the issue

(though looking at the article and checking my STL, it may be an issue... but that doesn't explain why the official results came back ok last season)

Andre splits the mesh on the radiator monitor prior to running the official result - so that it's consistent across all teams.
[/quote]
Yepp, that is what I do. I need to make sure that everyone has the same size triangles used for measurements.


You guys posted some pretty good stuff. If I actually manage to get my stuff solved I can possibly dig out some of my old material from the old KVRC days.

[yinlad]

Yepp, that is what I do. I need to make sure that everyone has the same size triangles used for measurements.

You guys posted some pretty good stuff. If I actually manage to get my stuff solved I can possibly dig out some of my old material from the old KVRC days.

oh ok that'll explain it then! Thanks for clearing that up. I'm going to run some tests with an actual mesh now to see what happens. I should expect better cooling, or just more accurate streamlines?

[Joe7218]

I lost basically all my floor downforce even though the pressure patches under the diffuser look better than ever. Does anyone have any idea what is happening here?

This weird low-pressure pattern is on both sides of the floor and has only appeared in this sim run. It looks like i can see the outline of the base of my sidepods in the pattern. is this just an error in the image generation or is this pattern the cause of my floor losing its downforce?
Thanks

[jjn9128]

I lost basically all my floor downforce even though the pressure patches under the diffuser look better than ever. Does anyone have any idea what is happening here?
https://i.imgur.com/tShWZSJ.png
This weird low-pressure pattern is on both sides of the floor and has only appeared in this sim run. It looks like i can see the outline of the base of my sidepods in the pattern. is this just an error in the image generation or is this pattern the cause of my floor losing its downforce?
Thanks

Are there 2 parts overlayed?


@Andre the submission for first race is tomorrow or 10th?

[cecca98]

Hi to everybody!
First of all, it's so great to take part in a so cool project.

I've recently joined this challenge with a friend and we are moving our first steps in Mantium. Reading your previous replies about the monitoring surface's mesh we checked ours. Obviously they were completely wrong. Do you have any suggestion regarding how to subdivide them in smaller triangles? We are having problems in solving that... and we want to check our mass flows before the competition in order to avoid bad surprises!
Thanks

[jjn9128]

Hi to everybody!
First of all, it's so great to take part in a so cool project.

I've recently joined this challenge with a friend and we are moving our first steps in Mantium. Reading your previous replies about the monitoring surface's mesh we checked ours. Obviously they were completely wrong. Do you have any suggestion regarding how to subdivide them in smaller triangles? We are having problems in solving that... and we want to check our mass flows before the competition in order to avoid bad surprises!
Thanks

My method's a bit of monkey motion but produces a good mesh - I export a step file of the rad monitor surface from the CAD then use gmsh to create a 2-d mesh and export it as an stl. Unfortunately there's a bit of a miscommunication here because I then have to shrink that stl in meshlab by a factor of 1000 to get it in metres for the MVRC software. Probably because the CAD is set to mm by default.

Though this is a bit long winded, it's not too tedious because I'm not iterating my sidepod/rads all that often. I probably use too fine a mesh because it takes a little while to seed all the streamlines in post-processing.


Left is my mesh right is a standard CAD stl export

[variante]

Do you have any suggestion regarding how to subdivide them in smaller triangles? We are having problems in solving that... and we want to check our mass flows before the competition in order to avoid bad surprises!
Thanks

You can make that surface not actually flat: a slight curvature should be enough to force your STL converter to triangulate the surface properly. Obviously, make sure to still tick the "fine" option (or whatever) for the conversion.

This method requires some more CAD work, but allows you to avoid 3rd party softwares or further complications.

the submission for first race is tomorrow or 10th?

I'm 99% sure it's 10th. And results come up one or two weeks later.

[Joe7218]

Are there 2 parts overlayed?

I dont think so but Ill double check, thanks

Hi to everybody!
First of all, it's so great to take part in a so cool project.

I've recently joined this challenge with a friend and we are moving our first steps in Mantium. Reading your previous replies about the monitoring surface's mesh we checked ours. Obviously they were completely wrong. Do you have any suggestion regarding how to subdivide them in smaller triangles? We are having problems in solving that... and we want to check our mass flows before the competition in order to avoid bad surprises!
Thanks

If you are using inventor, you can change the maximum length of each stl triangulation. A small enough maximum length will force it to triangulate properly. That's how I do it

[LVDH]

@Andre the submission for first race is tomorrow or 10th?

10th.

I lost basically all my floor downforce even though the pressure patches under the diffuser look better than ever. Does anyone have any idea what is happening here?

This weird low-pressure pattern is on both sides of the floor and has only appeared in this sim run. It looks like i can see the outline of the base of my sidepods in the pattern. is this just an error in the image generation or is this pattern the cause of my floor losing its downforce?
Thanks

Two parts on top or the part in question is not closed. You are seeing inside and outside pressure.


It took me some time to fix some of the issues, I was looking at but I made a breakthrough last night. I will try to roll out the new version this evening.

[cecca98]

Thank you for all the suggestions!

I've tried a combination of two methods: a slightly curved surface and then post processing in gmsh.
Now it looks much better, even if it can be furtherly improved.

Running now a simulation... let's see if it works properly.

[Joe7218]

I'm really at a loss with what's happening with my floor performance. I've lost 80% of my downforce (currently making -0.2) and the only thing I've changed is the sidepods slightly. The floor plank is still producing the same amount and the pressure patches look better then they did when the floor had a cl of -1.2? The pattern is still in the pressure plots though I've double-checked that there is no overlapping parts

[jjn9128]

I'm really at a loss with what's happening with my floor performance. I've lost 3/4 of my downforce (currently making -0.3) and the only thing I've changed is the sidepods slightly. The floor plank is still producing the same amount and the pressure patches look better then they did when the floor had a cl of -1.2?

What's the top surface doing? Have you got more low pressure above or less high pressure? Outwash around the front of the floor can affect the high pressure region ahead of the rear wheels or the peak diffuser flow. Is your total force better even if the floor is worse?

Difficult to help without pics but understandable if you're not keen to share.

[LVDH]

So, I just uploaded a somewhat fixed MFlow version. Mainly I wanted to pipe the mesh and solver log back into the MFlow console, which works again. Also I have added a csv export. However it seems impossible to also add a header line to the csv file. I have no idea why and will include it the following days.

I somehow missed to send you the one week notification email last weekend. The next race is getting very close! There is a possibility that we will delay the deadline be a few days though. I am discussing a certain rule change with Richard and I want to always give you a minimum of one week between a new rule and a submission. With some luck he will post the new rule today.

[jjn9128]

A rule change in what area? How big a change are we talking about here?