[KVRC] Khamsin Virtual Racecar Challenge 2016

[julien.decharentenay]

body
wing-front
wing-rear
cooling-intake
cooling-exhaust
engine-intake
engine-exhaust
hx-front
hx-rear
parts-offset.txt

If this is for the fallback option 2B, best to use inlet-cooling in place of hx-front and inlet-exhaust in place of hx-rear.

I have the impression that Opt1 will be a little more convenient if the Opt2/B inlets areas will be constrained. In my opinion (but we could wait after the pre season race results) the Opt2/B inlets/outlets surfaces would be free or with a lower minimum area (40000mm2?), but with the same pressure×area differential.

The minimum areas are really there to make sure that our constraints parameters are not leading to tiny sidepods. For option 2/B we reduced the pressure force to account for the modelled pressure loss at the air intake/exhaust in the cooling ducts.

Julien can confirm, but I believe that for the first round at least, we will need to use the fallback method for the entries using K4.1 option 2.

Confirmed. I have still to get through to get the porosity parameters finalised.

Hi, could you confirm that, if I run an Opt2/B with OCCFD, naming the heat exchangers surfaces as "cooling_inlet" and"cooling_outlet", I'm simulating the same official bc that will be applied during a race with Opt2/B?

Confirmed. Essentially the boundary conditions are the same. It is only the extract threshold that changes due to the modelled losses at the intake/exhaust and within the ducts themselves.

Has the OCCFD 'test' setting been changed? I ran it in AWS and it was still running over 24hrs later so terminated it. Previously it was over and done with in minutes.

No, it should not have happen. The simulation should be over in minutes. I will check and report. Also I haven't had time to look into the cheaper option - it should be a little cheaper, but not massively. The computational time should be similar to the one for last year.

You could also try to import the stl into sketchup and to translate it into the right place.

Importing STL into sketchup can take a long time (all night in some cases). Personally I like ParaView to check the min and maximum limits of the STL. But ParaView is painful to translate the STL, and I would use netfabb (free) for the translation. Meshlab can also be used a little easier than ParaView.

[julien.decharentenay]

@RicME85 I made a mistake and the Amazon AWS instance do not start properly - regardless of the option. I will correct the issue and send you an update. I am sincerely sorry.

[Alonso Fan]

so I just updated occfd to version 008 and I get a lot further into analysis, but it seems some problem still persists



I left my pc on for an 2 hours or so and when I came back, I had a windows firewall prompt asking me if I could allow simplefoam.exe and one of the meshing tools to run. this only happened after simulation 0 and simulation 1 had been completed, and the previous solution had been mapped on to the new mesh. it's weird because occfd had no problem using simplefoam or the meshing tool before in sim0 and sim1.

any ideas?

i'm now currently running the single core analysis, i'll post back once it finishes

[LVDH]

Importing STL into sketchup can take a long time (all night in some cases). Personally I like ParaView to check the min and maximum limits of the STL. But ParaView is painful to translate the STL, and I would use netfabb (free) for the translation. Meshlab can also be used a little easier than ParaView.

OpenFOAM contains two simple comands to do these things as well:
surfaceCheck shows you some info including the bounds
surfaceTransformPoints can among other things translate and rotate your stl files

[CAEdevice]

I think that to match the new parts with the template would be very difficult without a cad environment (unless you know the translation vector).

@Machin: I am sorry that I will not be at office untill Tuesday, but I have a lot of CAD tools dedicated to that kind of problems (my job is preparaing mesh for structural simulations). It would be better to start from your STEP and the to export a stl in the right place. What about submitting the stl as it is and then a resubmission after my export next Tuesday?

[Ft5fTL]

Pure Power Racing 15a is ready for the first race.

[machin]

@Machin: I am sorry that I will not be at office untill Tuesday, but I have a lot of CAD tools dedicated to that kind of problems (my job is preparaing mesh for structural simulations). It would be better to start from your STEP and the to export a stl in the right place. What about submitting the stl as it is and then a resubmission after my export next Tuesday?

No worries: I imported the STL that i created with Soliidworks this morning into SketchUp and it lands smack bang in the right place... so my antiquated Solidworks is obviously having problems with importing STL's, not exporting them... phew! (thanks for the offer though!)

[CAEdevice]

Pure Power Racing 15a is ready for the first race.

http://puu.sh/nMib9/d0e6895f6f.jpg
http://puu.sh/nMi5W/c20e941044.jpg

Wow! Best presentation, and the geometry looks promising.

[Ft5fTL]

Pure Power Racing 15a is ready for the first race.

http://puu.sh/nMib9/d0e6895f6f.jpg
http://puu.sh/nMi5W/c20e941044.jpg

Wow! Best presentation, and the geometry looks promising.

Well she will probably be around 5th-8th on the first race. I dont think i can compete with you, Variante or Mantium for now.

[LVDH]

Well, you have for sure won in the wow-department.

[Ft5fTL]

Well, you have for sure won in the wow-department.

Thanks.

[julien.decharentenay]

I left my pc on for an 2 hours or so and when I came back, I had a windows firewall prompt asking me if I could allow simplefoam.exe and one of the meshing tools to run. this only happened after simulation 0 and simulation 1 had been completed, and the previous solution had been mapped on to the new mesh. it's weird because occfd had no problem using simplefoam or the meshing tool before in sim0 and sim1.

The windows firewall prompt is because simplefoam is trying to communicate to the other simplefoam process(es). It is important to accept the communication to take place. Normally the firewall remembers this and only prompt once. This happens during simulation 1.

If you are referring to simplefoam from the previous version (from sourceforge), it probably prompted at some point or the openmpi library was somehow already authorised.

[julien.decharentenay]

@RicME85 I made a mistake and the Amazon AWS instance do not start properly - regardless of the option. I will correct the issue and send you an update. I am sincerely sorry.

I updated occfd to fix the Amazon AWS issue (no other change). Patch 009 can be downloaded from http://www.khamsinvirtualracecarchallen ... .1-009.zip. The Test option should turn around in the usual ten minutes or so.

[Alonso Fan]

I left my pc on for an 2 hours or so and when I came back, I had a windows firewall prompt asking me if I could allow simplefoam.exe and one of the meshing tools to run. this only happened after simulation 0 and simulation 1 had been completed, and the previous solution had been mapped on to the new mesh. it's weird because occfd had no problem using simplefoam or the meshing tool before in sim0 and sim1.

The windows firewall prompt is because simplefoam is trying to communicate to the other simplefoam process(es). It is important to accept the communication to take place. Normally the firewall remembers this and only prompt once. This happens during simulation 1.

If you are referring to simplefoam from the previous version (from sourceforge), it probably prompted at some point or the openmpi library was somehow already authorised.

Use this happened in simulation 1. I understand and have accepted the exception in firewall. Is this the cause of the error? Because I'm not sure for how long the firewall prompt was on screen before I saw it. My thinking is that it tried to run simplefoam.exe without firewall authorisation and therefore threw out an error?

Thanks for your help btw

[RicME85]

@RicME85 I made a mistake and the Amazon AWS instance do not start properly - regardless of the option. I will correct the issue and send you an update. I am sincerely sorry.

I updated occfd to fix the Amazon AWS issue (no other change). Patch 009 can be downloaded from http://www.khamsinvirtualracecarchallen ... .1-009.zip. The Test option should turn around in the usual ten minutes or so.

Excellent, will give it a go then try a normal run