Khamsin Virtual Racecar Challenge 2014

[RicME85]

You will no doubt have to install bluecfd and all the other bits and pieces that Khamsin requires. When you install the Khamsin plugin in Sketchup and go into the plugin settings it should have links to the various things you need to download and then path directions to change.

[CAEdevice]

What about organizing a general presentation of our cars?

[astracrazy]

it is something i have thought about, but really if people want to show them off they already will (or won't)

[cdsavage]

You will no doubt have to install bluecfd and all the other bits and pieces that Khamsin requires. When you install the Khamsin plugin in Sketchup and go into the plugin settings it should have links to the various things you need to download and then path directions to change.

Yep I'm aware of all of this, but I would like to know if using this skp and this version of khamsin will allow me to generate identical openfoam case files to those that the portal would output, ie the same mesh, same boundary conditions etc.

[CAEdevice]

Does anyone know what turbolence model Kashmin uses? If the model is k-epsilon, wich are the values of the typical parameters?

[cdsavage]

Im having a problem with using KVRC2014-Khamsin Model.skp from the downloads page - when moving imported geometry into some of the groups there is unwanted scaling and instancing applied to the geometry. Would it be easier to just list the boundary settings necessary for the body, front wing and rear wing, and the overall khamsin settings?

The settings mentioned previously (with the higher resolution front and rear wings) are the ones that will be used in judging the cars, right? Also have the cases been decided (speed, yaw)? This has probably already been covered somewhere but I just want to be sure.

[CAEdevice]

Im having a problem with using KVRC2014-Khamsin Model.skp from the downloads page - when moving imported geometry into some of the groups there is unwanted scaling and instancing applied to the geometry. Would it be easier to just list the boundary settings necessary for the body, front wing and rear wing, and the overall khamsin settings?

The settings mentioned previously (with the higher resolution front and rear wings) are the ones that will be used in judging the cars, right? Also have the cases been decided (speed, yaw)? This has probably already been covered somewhere but I just want to be sure.

This year only 100mph configuration (with no yaw) will be run.

[CottrellGP]

Hi all, the links on the Khamsin configuration page do not work for all the Khamsin addons, does anyone know were i can find the addons?

[RicME85]

just google for them

[machin]

Just thought I'd let everyone know that I have updated Virtual Stopwatch for this year's competition which I have just made available to the championship organisers, with the following changes.

Updates as follows:-
•New F1 power unit, with estimated power curve based on the fuelling limits mandated by the FIA. The power curve ramps up with peak power at 12000 rpm and then tails off... at peak power and full ERS 760bhp will available. This may or may not be true of the real engines, but it doesn't matter too much as it is the same for everyone.
•Weight of cars increased to 691kg (incl Driver) as per 2014 rules.
•The front to rear weight split is set at 46% front and 54% rear which is within the requirements set by the FIA.
•8 speed gearbox.
•Nurburgring (Nordschleife) lap added.

Regarding the mass split; you should try and aim to get your aerodynamic centre of pressure to match the weight split, with a slight preference, if any, towards the rear of the car, for the best lap times. That is 1.83m behind the front axle centre line

Good luck!

[julien.decharentenay]

@CAEdevice Turbulence model is k-omega SST with default openFoam parameters. I could try to dig them up for you if required.

@cdsavage Sorry about the issue with KVRC2014-Khamsin Model.skp. The settings are as follows:

General settings:
Tick off the "User high accuracy numerical scheme"
Mesh type: body fitted hex mesh with boundary layer
Characteristic mesh size: 1.02 m
Trim mesh: 1.02 m
Solver type: Isothermal turbulent flow
Swak4Foam/GroovyBC:
ramp=(time()<100) ? time()/100.0 : 1.0;
velMag=ramp*44.7;

Front wing and rear wing:
Velocity: 0 m/s
Mesh size: 0.003984375 (=1.02/2^8)

Body:
Velocity: 0 m/s
Mesh size: 0.00796875 (=1.02/2^7)

Wheels (at the front):
Variables:
center=sum(pos()*mag(Sf()))/sum(mag(Sf()));
position0=pos()-center;
radius=0.3256115;
vel=vector(0.0, -velMag*position0.z/radius, velMag*position0.y/radius);

Velocity value: vel
Mesh size: 0.00796875 (=1.02/2^7)

Wheels (at the back):
Variables:
center=sum(pos()*mag(Sf()))/sum(mag(Sf()));
position0=pos()-center;
radius=0.3256115;
vel=vector(0.0, -velMag*position0.z/radius, velMag*position0.y/radius);

Velocity value: vel
Mesh size: 0.00796875 (=1.02/2^7)

For the outer boundaries of the computational domain:
Inlet:
Variables:
vel=vector(0.0,velMag,0.0);

Velocity: vel
Mesh size: 1.02

Ground (wall boundary condition):
Variables:
vel=vector(0.0,velMag,0.0);

Velocity: vel
Mesh size: 1.02

Outlet (no backflow outlet)
Mesh size: 1.02

The above assumes that your openFoam installation has swak4Foam installed.
Note: the resulting setup will be very similar to the one generated by the portal, but I can't guarantee that it is identical. There are small things that the portal does that khamsin does not, such as the portal takes the wheel radius directly from the geometry - this can't be achieved with khamsin as the user is nominating the boundary conditions.

In the portal, convergence is assessed on the basis of residuals and convergence of the COP.

[julien.decharentenay]

Just a reminder that we will be presenting the submission portal tomorrow. Luke may be able to join in occasionally, but is unlikely to be able to be there all the way through.

A little bit more on the Hangout on Air so that you know what to expect. Hangout on Air is a multi person (max 10) video conference. It is "on Air" as the video conference can also be viewed by non-participants - the non-participating viewers have about 10 to 30 seconds lag. At the end the video will be uploaded to YouTube - I will do minor editing. To be a participating viewer I think that you will need a Google account.

I will start the Hangout on Air about 15 to 20 minutes prior to the planned starting time. Around 10 minutes prior to the starting time, I will set the Hangout to be "on Air" and will distribute the link via email, twitter (#kvrc2014) and here. Click on the link, which will take you to the viewer page. There, you can choose to view or participate. Up until the starting time, there will just be a screenshot (and I will probably be getting a glass of wine). The video conference has a chat facility (accessible to participants) and a Q&A accessible to non-participating viewers. You can also post questions on my email julien@khamsinvirtualracecarchallenge.com or through twitter #kvrc2014. I will try to monitor both.

It is made to be an interactive session, so feel free to ask questions and interrupt the presentation. I have about 12 slides to go through, so it should not take too long. But I will have to keep to a maximum of 1 hour as I am supposed to have a chat with Luke re the challenge organisation afterwards...

Last, but not least, my internet connection can be temperamental. So it may drop off at time, but don't worry I will be back...

[julien.decharentenay]

Hi all, the links on the Khamsin configuration page do not work for all the Khamsin addons, does anyone know were i can find the addons?

Can you list which one? You do not need to install all of them and I would be happy to hear of which one are not working...

[julien.decharentenay]

Submission presentation event is live now. URL is https://plus.google.com/u/2/events/c0k4 ... habn5e86mk - Click on "Start" to join the video chat or "Live" to just view it. Drop me a chat/question to let me know if you are online.

Julien

[julien.decharentenay]

Thanks a lot for those who took/are taking or will be taking the time to view it. If the video is showing 34 minutes, you will need to skip quite a bit at the beginning. I will try to edit this asap. The video can be viewed at the event URL above.

The presentation slides are also available at: http://www.slideshare.net/JuliendeChare ... esentation

Anything unclear, let Luke or myself know.

Feedback on the Hangout on Air concept would be welcome too.