[KVRC] Khamsin Virtual Racecar Challenge 2016

[CAEdevice]

Thank you.

Do you think thay the numeric inaccuracy is so big to affect significantly the CoP value (I mean, more than 50mm over 1650mm)? Du you think that a finer mesh over the floor/diffuser could help?

[LVDH]

I never looked too deep into it as the approach was at least consistent and that way predictable. Also as the guys came up with the good idea of the corrected CoP it was never a big issue for me, it is only a small detail. Only stupid CFD engineers can go crazy over this kind of stuff and exchange many emails about it.

Yes the parameters you mentioned will affect CoP but in a different way. This was only math you can do on paper.
Let us not worry about this too much any more.

My approach is to keep everything as close as it is for this season anyways to ensure a smooth transition, in case everyone is fine with me setting up a new championship.

[CAEdevice]

And what about about the cooling issues for this season?

By the way: I can't wait to race again!

[LVDH]

Regarding cooling, I suggest we run with ducts and heat exchangers as it is implemented in MantiumWFlow. If this seems to hard for too many people we could go back to last years rules.
...
The simplified cooling solution we had this year does not convince me.

Actually right now I am doing a test. The imposed cooling BCs work in MantiumWFlow as well. I forgot about that.
Yet I still think we should either go for ducts with heat exchangers or we go back to the 2015 rules and eliminate the power down grading for this year.
I hope option 1 sounds more appealing.

[CAEdevice]

Regarding cooling, I suggest we run with ducts and heat exchangers as it is implemented in MantiumWFlow. If this seems to hard for too many people we could go back to last years rules.
...
The simplified cooling solution we had this year does not convince me.

Actually right now I am doing a test. The imposed cooling BCs work in MantiumWFlow as well. I forgot about that.
Yet I still think we should either go for ducts with heat exchangers or we go back to the 2015 rules and eliminate the power down grading for this year.
I hope option 1 sounds more appealing.

The second option would be impossible for me (and for everyone did not design the car only with the aesthetic criteria).
The first one would be great, I hope it works.

Are you sure that, only for this year, a compromise obtained modeling ducts (at least the first 200-250mm) and measuring the resultant force on the internal template surfaces (front and rear, without imposed flow) would be so bad? Quite far from the best solution (porous media) but much better than 2015 rules.

[AratzH]

I would be happy with both solutions proposed, although I think LDVH's might be easier for everybody, but him.

Anyhow, regarding the cooling issue, I think we should try to keep as much of the ducting as possible to maximize the realism. If the porous solution is not possible what about having a ruled orifice plate? We could define an area with a hole that must lie in the center of the heat exchanger and could be calibrated to create the desired pressure drop for the defined flow. Then measuring the actual flow in the ducts could be enough to determine the performance. I might pose other problems (orientation of the orifice regarding the incoming flow limiting flow or things like that) but we would for sure remove the, I think worst, problems of the imposed boundary condition model.

[CAEdevice]

I would be happy with both solutions proposed, although I think LDVH's might be easier for everybody, but him.

Anyhow, regarding the cooling issue, I think we should try to keep as much of the ducting as possible to maximize the realism. If the porous solution is not possible what about having a ruled orifice plate? We could define an area with a hole that must lie in the center of the heat exchanger and could be calibrated to create the desired pressure drop for the defined flow. Then measuring the actual flow in the ducts could be enough to determine the performance. I might pose other problems (orientation of the orifice regarding the incoming flow limiting flow or things like that) but we would for sure remove the, I think worst, problems of the imposed boundary condition model.

I could be a good fix of the present issue.

[CAEdevice]

I quit as contender and run the championship.
I would call it MVRC and you guys could use a simplified version of MantiumWFlow and also run simulations on the online platform I am working on.

Near future?

[LVDH]

This car looks so much better now.
I am woroking hard to make sure that you have predicted the future correctly.
Using porous media for the heat exchangers is no problem.
It is only a matter of setting up a vote on weather we want a porous media heat exchanger and adjust engine power according the cooling air flow or the 2015 approach. I think there are online tools to perform such votes. Maybe you can help me and set one up Matteo, or anybody else?

Here are my next plans. I will work on a very basic homepage and also a first version of MantiumWFlow I can send out to you guys. Both will first not be perfect but that way we can get started faster. A data exchange portal and these details we will need to make everything smoother will follow later. I hope the new season can be announced in about three weeks with the first race some two weeks later. Yes, it sounds like ages after all this delay but I will build everything from scratch.

Some changes that will pretty sure happen are:

• CoP as calculated by OF
• Standard coordinate system (Y points from left to right)
• Better mesh settings
• Strict enforcement of rule 1.3

The last (two) rules are about streamlining the process for Chris and also getting the CFD simulations done faster. I have looked into some issues of last year. Chris spends too much time on explaining how to make acceptable quality CAD data. Apparently the CAD is then sometimes still not good enough and the CFD simulations get stuck. This is why some races took so long to finish.
Because of that MantiumWFlow will warn you guys about bad quality stl files. This check is based on a utility in OF. It is called surfaceCheck. So right now everyone with OF can check their CAD themselves. Mainly this is about closed stl files. Non-closed files will not be accepted anymore. With the improvements in the meshing process the other quality criteria you could come up with do not matter too much and we should get results much faster. So once more: Only closed stl files will be accepted.

I will try to create a first simple OF case with some post-processing which I will make available this week (hopefully) so you guys can get back on designing your cars.

[CAEdevice]

The new MVRC is very promising.

About the vote/poll: if you have a dedicated domain with a cms installed (preferably wordpress), it would be quite easy to collect the partecipants into a community and to install a voting plugin. I am quite sure it is also possible on F1tech/forum (if not we could vote simply writing yes/not in this thread).

Personal opinion: I am not a fan of the democratic processes, if I were in you I would just switch to porous media using the pressure data to define engine power as in 2017.

About geometry: I completely agree with your proposal. There are many tools (including OF) to check if the geometry is closed (and other things). I would be even more severe accepting only STEP, since STL was designed to "finally export" a file and it makes difficult to fix things likes cuspides or small surfaces (and automated geometry check).

[LVDH]

Good news everybody,
I have received the three thumbs-up from the old KVRC staff.
This means that I will get working on a new homepage this weekend and you guys can then enroll into the new championship.
One of the new things to get exited about will be start numbers that from now on every car will carry. I guess the number 1 will go to Variante.

I am working on a good and simple process which will make the championship as accessible as possible to everyone. This means getting OpenFOAM to work on Windows. I know you guys have been using third party solutions which seemed to be fine. However there are good reasons to use newer versions of OpenFOAM. I would prefer 3.0.1 or maybe 4.0. It seems though that the plus versions are easier to get running on Windows. Maybe some of you guys could try and comment on these two options for Windows:
http://openfoam.org/download/windows/
http://www.openfoam.com/download/install-windows.php

[CAEdevice]

Number 98 for me.
OF "classic" (4.0) or "plus" is the same for me, but the "plus" installation on Windows should be easier to manage.

[Alonso Fan]

Number 14 for me please

The only open foam I've used is the one recommended for occfd. I'll happily install any of the above mentioned as long as someone can explain to me how to use it for my car

[etsmc]

How simple are the simulations going to be to run? OCCFD was easy to run a simulation just a bunch of files in a folder and then select the simulation you want to run..
is it going to be as easy as this to do?
will the installation be an easy process or will it be a step by step thing such as OCCFD?

oh and 84 would be my choice.

[CAEdevice]

How simple are the simulations going to be to run? OCCFD was easy to run a simulation just a bunch of files in a folder and then select the simulation you want to run..
is it going to be as easy as this to do?
will the installation be an easy process or will it be a step by step thing such as OCCFD?

oh and 84 would be my choice.

I think it will be as easy as OCCFD: http://mantiumcae.com/mantiumwflow/