[MVRC] Mantium Virtual Racecar Challenge 2018

[Team_Bart]

Congratulations to CAEdevice for winning the first race!

I have a problem with running simulations at the moment. With some help from MCAE Support I found out there is a part with an unclosed surface, probably this causes the problem. Does anyone know how I can find this surface and fix it? I'm using SolidWorks. Therefore in my thinking it is actually a bit strange there is created an unclosed surface from a solid body.

[CAEdevice]

Congratulations to CAEdevice for winning the first race!

I have a problem with running simulations at the moment. With some help from MCAE Support I found out there is a part with an unclosed surface, probably this causes the problem. Does anyone know how I can find this surface and fix it? I'm using SolidWorks. Therefore in my thinking it is actually a bit strange there is created an unclosed surface from a solid body.

Hi, if you are using SWX the problem can be caused by a cusp that can have origin from a blend between non compatible surfaces.

If you don't mind, I can take a look to the SWX native file you used for the first race

[Team_Bart]

Hi, if you are using SWX the problem can be caused by a cusp that can have origin from a blend between non compatible surfaces.

If you don't mind, I can take a look to the SWX native file you used for the first race (email: matteo@caedevice.net )

Hi that would be nice, I sent you the file!

[LVDH]

Maybe this helps:
https://mantiumchallenge.com/locating-h ... mulations/

[CAEdevice]

Hi, if you are using SWX the problem can be caused by a cusp that can have origin from a blend between non compatible surfaces.

If you don't mind, I can take a look to the SWX native file you used for the first race (email: matteo@caedevice.net )

Hi that would be nice, I sent you the file!

Just received! I will take a look today.
The repair of a STL file (LDVH link) is a possible solution, but it would be better to solve the problem where it begins, so the STL translator will work better.

[JJR]

Congratulations to Matteo for great victory! Once again perfect car.
Im messing up with ballance of my car. My driver had hard time in it fighting with rear all the time .
Now it´s time to put some downforce on car.

Great presentation of results from mvrc team. I like those trap speeds. Thanks for that.

[Team_Bart]

Maybe this helps:
https://mantiumchallenge.com/locating-h ... mulations/

Thanks! Looks like a good tutorial, I'll try it. Still it is quite strange to me that this was not a problem during previous simulations. Where those just good luck or are there other parameters, like meshing for example, that has influence on it?

[variante]

Still it is quite strange to me that this was not a problem during previous simulations.

Were you using "fast" setting for your simulations? Because that uses larger cells for the mesh, thus closes more holes on the bodywork than the standart setting.

BTW I'm looking forward to MadMatt's article!

[Team_Bart]

Still it is quite strange to me that this was not a problem during previous simulations.

Were you using "fast" setting for your simulations? Because that uses larger cells for the mesh, thus closes more holes on the bodywork than the standart setting.

BTW I'm looking forward to MadMatt's article!

Yes I did use the fast settings.
BTW see the figure below for one of the results it is producing. Can it probably be something else?

[LVDH]

Looking at the flow field will usually not help you that much to understand where the simulations fails as when these crazy CFD simulations do fail the indeed explode and show crazy stuff. Most likely the reason for something like this is that the mesh is bad. It is possible that you have open geometries. Maybe the engine inlet does not perfectly seal with the car body? The general mesh settings have not changed now for more than two years as far as I know right now, yet you can always be unlucky and have designed something that results in a bad mesh. What you can do is check the solver.log file. In there the min and max values of velocity and pressure are logged. In the last iterations the solver did before it gave up you will find velocities in the range of a few thousand. Go back a few iterations before everything was super crazy but already crazy and check the location of min and max pressure. I bet the two coordinates are very close together. Check out where that is in relation to your car and try to adjust the geometry in that area a few millimeters. This often does magic.

[variante]

Another thing is turning into reality right now. As I said, that bad weather made it possible to have some flow visualizations:
https://mantiumchallenge.com/wp-content ... rfaces.gif
Better quality can be found here:
https://mantiumchallenge.com/interestin ... mans-2018/

For whoever is interested: These are actually Lambda2 iso surfaces at Lambda2=35000. If you like, I can add these to the automatic post-processing. I can also release images that show much more of the cars. Variante has pretty interesting vortices along his car.

I forgot about this one... Yes, it would be great to add this stuff! I'm trying to do it by myself, but with little success...

[CAEdevice]

Hi, how is the development going?

During the last weeks I played with some new ideas, but none of them worked as expected.

At the moment the most promising details are:
- new HX position ("F1 like"): no advantages by itself, but it allows more room inside the sidepods (I have some ideas about using that space, but not before the third race)
- new diffuser: the one I am using now is just a "cutted" (in the step region) version of the one I was developing with the old rules

I am considering to publish a "development" blog.

[etsmc]

My development seems to have gone OK. got a proper front wing design going on that is a bit easier to adjust the flap angles.
my legality issues should be sorted now also.
I have a couple of things in my head that i would like to change but don't think i will have the time to implement the changes.

Still cant seem to make the downforce of the front runners.
I think my aim is to try and catch back up to PurePowerRacing.

[machin]

Still cant seem to make the downforce of the front runners.

I just ran a few cars through Virtual Stopwatch, and most (but not all) of the round 1 cars would be quicker around Sepang if they reduce drag, compared to increasing downforce...

...of course, that doesn't tell you whether it is easier to decrease drag compared to increasing downforce...

[variante]

I just ran a few cars through Virtual Stopwatch, and most (but not all) of the round 1 cars would be quicker around Sepang if they reduce drag, compared to increasing downforce...

Keeping efficiency constant, right?

...of course, that doesn't tell you whether it is easier to decrease drag compared to increasing downforce...

Reducing drag is very difficult without incurring in a huge CoP shift. For example, reducing Rear Wing for less drag is easy, but reducing Front Wing doesn't necessarily translate into less drag (given the same efficiency).

Also, if you already are at the point of maximum efficiency of your car, reducing drag will also reduce efficiency, so you don't want to exaggerate even if you were to race at Monza.
My car is currently above the point of maximum efficiency (=more downforce, more drag than ideal), but I can't tune it down too much because my CoP would shift towards the front a lot. And if I try to correct the CoP shift with less Front Wing, the car gets less efficient...

So right now I'm finding easier to gain performace translating the point of maximum efficiency upwards, thanks to new geometries that produce more downforce with similar drag.
If I had to focus on drag reduction, I'd go for front wheel covers, mirrors, canopy,... all those elements that don't have a huge impact on downforce and CoP.