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Ah yes i seen that, didnt really understand what it was but now i do, how long did you wait for until you got the result back?RicME85 wrote:Its dead simple and we have been through it before.
Just use the portal Julien has set up, I did yesterday, its as simple as loading the sketchup file and putting in a couple of numbers Julien posted in here a few pages ago.
Thanks man, just sorted it out and sent my car off!RicME85 wrote:it took a while, uploaded the file at around 6pm and got the link to download the results at about 7am but it was easy to do and didnt use my PC to do the brain work. havent looked at the results yet as there was an issue with the Amazon server and it denying me access to the result file so had to get in touch with Julien.
Hi there. Nick, great job for following this up and keeping the conversation flowing. If you want to contact me, try info@hibouscientificsoftware.com.au or post on http://www.cfd-online.com with [KVRC] I am checking it more frequently than F1Technical.
Re wind tunnel model: please download from: https://dl.dropbox.com/u/40499338/KVRC2 ... 180mph.skp. It has annotations to try to explain how to set things up. Nick, can you supply the wheel/suspension for them to run the simulations?
For the 2012 test run, I used the following workflow:
- Set the car up in a stand-alone model (i.e group the body and the wheels in separate groups, i.e 5 groups) and then group the car in a single group;
- Move the car so that the front wheels are aligned with the red "x" axis with the car facing downwards (in a top view). The lowest point of the wheel is set to 5mm below the ground plane (z=0);
- Open the root model and copy and paste the wind tunnel around the car.
The above workflow requires that the car boundary conditions are setup again, but it is easier than trying to copy and paste the car geometry. The model provided should allow the way described above or to copy and paste the car geometry.
If you want to run preliminary simulation, you can neglect the tyre rotation and just copy and paste the whole car into the body group.
Wind tunnel only:
180mph scenario: https://dl.dropbox.com/u/40499338/root% ... 180mph.skp
100mph scenario: https://dl.dropbox.com/u/40499338/root% ... 100mph.skp
100mph scenario with 3degree yaw: https://dl.dropbox.com/u/40499338/root% ... %20yaw.skp
To run a test to check the configuration, it will be easier to just run a test. Use: https://dl.dropbox.com/u/40499338/Khams ... mplete.skp for example. Load the skp file in SketchUp, activate Khamsin tool and right-click -> Analysis -> go (local).
With the wind-tunnel:
- Open the skp file;
- Paste or import the car - with the provided wind-tunnel skp file, paste the car into the car-body group so that the imported car is part of the car-body group in the wind-tunnel skp file;
- If you are not able to paste the car into the car-body group (but do ensure it is imported as a group), you will need to do the following:
+ Khamsin tool -> right-click -> Define -> Volume
+ left button press (i.e press but do not release) on the group in which your car is imported, this should display a local menu;
+ move the mouse to the entry "Volume 0" - it should get highlighted in red, and release the left button;
+ Do the same and select "Close"
+ right-click -> Define -> Boundary Conditions
+ double left click on the the group in which your car is imported, this should display the boundary condition panel;
+ Change the name to "car" and the mesh size to "0.01"
+ Select "Close" by left button press over the group, etc.
- Then you can run the analysis: right-click -> Analysis -> go (local)
1. swak4Foam: it would be required for the wheels - to account for the rotation of the wheels. If you do not include the wheels, you can just untick the box.
How to install it? I am using the blueCFD distribution, which includes swak4Foam. blueCFD-SingleCore is a free subset of blueCFD, which does not include swak4Foam. I am unsure how it can be added manually... You can purchase blueCFD from blueCAPE (check price with them, but believe it is around Euro70). I will drop them an email to see if they might be willing to add swak4Foam to their blueCFD-SingleCore for the KVRC.
There are a number of alternatives:
- build a port of openFoam and swak4Foam for windows on your own - probably time consuming and frustrating experience, not for the faint hearted;
- install openFoam and swak4Foam on a Linux computer on the same network as your windows box and use right-click->analysis->remote->linux - it is probably the easiest way, but require two computers on the same network;
- use Amazon EC2 (right-click->analysis->remote->Amazon EC2). If you want to do this, let me know as I need your amazon user id to allow access to the image. It is reasonably experimental, and Amazon EC2 will charge you per CPU hour (not expensive though).
2. Individual components: Just place it the same way as you did with the car. You probably want to get the correct height above the ground to correctly account for ground effects, otherwise the position in the domain should not matter much. Just be aware that a component that is optimised by itself may behave differently when included with the car. To optimise run time, you can look at a number of aspects: do you need to run for 1000 iterations? Can you coarsen the mesh resolution?
The windtunnel links dont work so I have uploaded the files I have - http://www.mediafire.com/download/fgli3 ... tunnel.zipFor post-processing:
- Check the analysis output: right-click>Analysis>Output. Scroll down to the near the end and you should have the forces (in newton) and moment (in newton.meter to the 0,0,0 point). Both have two components: pressure induced forces/moment and viscous (molecular and turbulent) induced forces/moment.
- ParaView: right-click->Analysis>Paraview. In paraview:
+ Change time from 0 to the latest one (click on the up arrow);
+ Click on the apply button (on the left side of the screen);
+ Change the variable (may be called Solid Color) and may have to change the representation to "Surface" (it is a bit on the right of the variable in the toolbar) - on the left of the variable drop down, there are three buttons: rescale, edit scale and show legend (from right to left);
+ Just under the variable and representation in the toolbar, there are a few filters than can be applied: the section one is a good one.
+ Also, right-click (in the pipeline browser) on open and select the "xxxx.foam" file
+ In the object inspector: untick the internal mesh and tick the name containing car or car-body, then click apply. It should only show the car body. Check the pressure on the surface to see area of high and low pressure.
If all fails, have a check at the documentation...