[MVRC] Mantium Virtual Racecar Challenge 2019 (Grand Prix Cars)

[machin]

in general air-fluid radiators/HX have a core with fins normal to the flat frontal surface....

Yes... certainly that is my experience too (20 years ago my Uni final year project was doing heat exchanger design optimisation with Ilmor, the company that built the Mercedes Formula 1 engines at the time...) but I wondered if the design had moved on since...

[Thomas2019]

In any CFD if you calculate porous media for car radiators you follow what CAEdevice explained. I had a quick look on porous media definition in MVRC cases, and it looks like that in directions other than normal, there's "0", shouldn't it be negative value to give "infinite resistance" in these directions? I had some doubts already with few of my simulations about air passing through HX.

The porous media settings in OpenFOAM should look something like this, in system/fvOptions:

porosity_hx_v01
{
type explicitPorositySource;
active yes;
explicitPorositySourceCoeffs
{
selectionMode cellZone;
cellZone hx_v01;
type DarcyForchheimer;
DarcyForchheimerCoeffs
{
d ( 2750000 55000000 55000000 );
f ( 60 1200 1200 );
coordinateSystem
{
type cartesian;
origin ( 0 0 0 );
coordinateRotation
{
type axesRotation;
e1 ( -0.574 0 0.819 );
e3 ( 0 1 0 );
}
}
}
}
}

You define a local coordinate system (e1 & e3) which you have to change when you change the rotation of the HX.
The d & f coefficients are then defined based on your local coordinate system. For the HX models, it is good practice to have the resistance of the two "blocked" directions (i.e. local y & local z) to be at least an order of magnitude higher than the resistance in local x.

Thomas

[LVDH]

Thanks for this Thomas, here is some additional input: https://openfoamwiki.net/index.php/DarcyForchheimer

In the past, I have also asked myself about only blocking the flow in one direction as the currently used model pretty much forces strong flow resistance in both directions planar to the main surface. However you can set the values any way you want, the flow will always be aligned with the shortest path through the porous medium. So trying to take into account that the air could travel parallel to the fins simply does not change anything (at least with realistic resistance values for automotive heat exchangers).

I totally forgot to send out the reports. That will happen soon.

[rjsa]

Hi Andre, can you please publish my first race too? I was away and didn’t get it.

[wb92]

maybe short off-topic, but it's almost half of the season and teams (like me ) would like to know where to put efforts for car development, so would next season continue 2017-2020 F1-car-like scheme or it would rather turn into proposed 2021?

[Alonso Fan]

There's plenty of interesting stuff going on there while I was forcing my car's rear to work finally... I need an elephant on the rear axle to find the balance if anyone is interested 'how it's going'

If you do find one, let me know if he has an older brother...

Oh my four days to go... Better get ringing around then haha

[rjsa]

I’ve understood around here that barge boards are supposed to go on the high res folder. Is that right ?

[machin]

I’ve understood around here that barge boards are supposed to go on the high res folder. Is that right ?

Yes that’s right... we changed it this weekend... there are some other small clarifications (highlighted blue) that everyone should check quickly;

https://mantiumchallenge.com/mvrc-rules-2019/

[machin]

maybe short off-topic, but it's almost half of the season and teams (like me ) would like to know where to put efforts for car development, so would next season continue 2017-2020 F1-car-like scheme or it would rather turn into proposed 2021?

Andre and I have discussed this briefly, but at the moment there are no published FIA rules for the 2021 season... but maybe shortly we’ll get something to look at and then we can make some decisions about next year...

[CAEdevice]

@wb92: If you understand everything of your car now, you will use this knowledge in 2020 indipendetely from the rulebook.
Consider that I am using concepts from my 2016-2017-2018 cars that had a "slightly" different rulebook (LMPx).

[jjn9128]

maybe short off-topic, but it's almost half of the season and teams (like me ) would like to know where to put efforts for car development, so would next season continue 2017-2020 F1-car-like scheme or it would rather turn into proposed 2021?

Andre and I have discussed this briefly, but at the moment there are no published FIA rules for the 2021 season... but maybe shortly we’ll get something to look at and then we can make some decisions about next year...

October 31st they're supposed to be ratified and November 2nd they're supposed to be published on the FIA website. I'd be all for a change to a "ground effect"/Venturi floor car, IMHO it doesn't have to follow the F1 rules but could have a basis from the old Champ rules or even take from a number of series e.g. a Formula E style closed wheel car with a champ/Indy floor.

[rjsa]

I’ve understood around here that barge boards are supposed to go on the high res folder. Is that right ?

Yes that’s right... we changed it this weekend... there are some other small clarifications (highlighted blue) that everyone should check quickly;

https://mantiumchallenge.com/mvrc-rules-2019/

Got it, thanks.

[wb92]

@wb92: If you understand everything of your car now, you will use this knowledge in 2020 indipendetely from the rulebook.
Consider that I am using concepts from my 2016-2017-2018 cars that had a "slightly" different rulebook (LMPx).

That's clear, but so far it's what I shouldn't mostly do with the car, although wings are really cool
I don't have such privilage to have concepts from '16-'18, but don't worry, I will catch up

October 31st they're supposed to be ratified and November 2nd they're supposed to be published on the FIA website. I'd be all for a change to a "ground effect"/Venturi floor car, IMHO it doesn't have to follow the F1 rules but could have a basis from the old Champ rules or even take from a number of series e.g. a Formula E style closed wheel car with a champ/Indy floor.

That's why I ask, because maybe I could learn something more on current one to get some ideas for 'venturi' car

[LVDH]

maybe short off-topic, but it's almost half of the season and teams (like me ) would like to know where to put efforts for car development, so would next season continue 2017-2020 F1-car-like scheme or it would rather turn into proposed 2021?

Andre and I have discussed this briefly, but at the moment there are no published FIA rules for the 2021 season... but maybe shortly we’ll get something to look at and then we can make some decisions about next year...

It was supposed to be a surprise, but yes, we would like to have the new rules already for next year.
Keep in mind though that organizing this takes a lot of time. This is why this season started so late and the races are so tightly packed. The priority for next year will be to stretch everything much better out. So I hope Richard and I do not have to takes months of rest after the season. And also we have to see if something gets published by the FIA because we do not want to guess some rules.

[jjn9128]

Something like this would be interesting... maybe with the face-lifted Formula E front wing pods? I don't see why it has to follow F1 - those rules are so compromised.




Or maybe use the concept 2011 "ground effect" regs (without the standard floor part)