Star-CCM

This page contains resources for running and trouble shooting Star CCM+ on our MATLAB sim queue. For a detailed overview of Computational Fluid Dynamics (CFD), its theory and best practices, see the CFD section of the Aero Handbook.

Sim Computer Connection (RDP)

As of the F26 design cycle, the aero department of GTMS relies on two CPU's operated out of our own shop space for running CFD simulations. This is a big alternative to using a cloud-based computing cluster like PACE that requires the use of slurm and server based file transferring. Computing clusters are often faster, but more expensive and (in the case of the school's computing cluster) unreliable. The school system works off of research tokens, and without them the cluster can't be accessed. Using our own computers with a POD STAR-CCM+ license allows for unlimited access to both running sims and analyzing them locally. There should also be work towards integrating these local CPU's with a dedicated GPU to reduce solver time.

The two CPU's are affectionately named "Murray" (like Gordon) and "Newey" (like Adrian). Both computers have remote desktop connection (rdp) enabled from IT. To connect to either computer, use your GT credentials and the following names:

Newey: me06w1710lab07.ad.gatech.edu

Murray: me03w1710grd04.ad.gatech.edu

Monitoring Runs (Connect to Server)

Our sim queue utilizes command-based execution of meshes and solutions to eliminate the use of the GUI and thus improve runtime efficiency. However, some runs do require constant monitoring as it moves through each iteration. You can achieve this through the server function. Our computers are not server-based, in that the only "server" we connect to is the host computer itself. To do this, go to File -> Connect to Server. The default host and port should be sufficient to find the currently running .sim file. Hit Scan -> Ok and you should see the active .sim file in the GUI.

To Disconnect, do not exit the program normally. Instead, got to File -> Disconnect. This will safely close the GUI without risking halting the solution or mesh.

MATLAB Sim Queue

GitHub Repository

Various Scripts

add.m

• add FXXYYY
• adds already-prepared runs

aeroload.m

• outputs forces from a run, rather than coefficients

arcNums.m

• uploads run numbers to SharePoint

arcPeri.m

• uploads run Periview files to SharePoint

arcRuns.m

• uploads run folder to SharePoint

comp.m

• comp FXXYYYY FZZ####
• similar to compareRuns.m, but for two runs

compareRuns.m

• compares any number of runs through several parameters, at both part and vehicle level

cq.m

• cq
• clears the active queue

getSharePointDir.m

• returns user SharePoint directory

makeRun.m

• generates run files from baseline run

mq.m

• mq
• displays mesh queue

q.m

• q
• displays solve and mesh queue

runMeshQ.m

• runs mesh queue

runQ.m

• runs queue with the runs in the queue
• runs can still be added to queue once it is initialized

status.m

• status

• continuously displays solve and mesh queue
• discontinued by hitting ctrl+c(this command is true for MATLAB in general)
• automatically run when from runQ.m command

Common Errors

File Related Errors

If the scripts error due to not being able to find a file, ensure the account which is being used has the user's GT OneDrive mounted to the file explorer. getSharePointDir.m uses the system variable "OneDriveCommercial" , which will return no value should your GT OneDrive not be accessible. Additionally, getSharePointDir.m only looks two levels deep within your OneDrive for the Documents - GT Motorsports folder from SharePoint, so if this folder is nested within more than two folders from your OneDrive, it will return no result and the script will error.

The scripts assume the following paths:

from Sharepoint:

Periview: ...\Documents - GT Motorsports\Aero\CFD\Periview

CFD Numbers: ...\Documents - GT Motorsports\Aero\CFD\CFD Numbers

CFD Archive: ...\Documents - GT Motorsports\Aero\CFD\CFD Archive

Meshing Errors

Overlapping Surfaces

The mesh may fail if two surfaces overlap each other or intersect each other.

Sim Queue Errors

unrecognized function or variable 'bslsimtype'

This error appears when creating a new run with a baseline not in the CFD folder. This can be because the sim is not loaded into the computer being used in the correct folder, or it does not exist. To fix this, ensure that the sim folder, with the .sim file, is stored locally on the CFD folder (not the CFD folder in SharePoint).

Post-Processing

Post-processing CFD, or examining the simulation's results, can be broken up into two categories, qualitative and quantitative, as discussed in the aero handbook. For quantitative data, such as overall and by-part Cl, use comp.m or compareRuns.m, as described above. For qualitative data, see the Periview section below.

Periview

Periview is our qualitative post-processing tool, used to look at various plots from data outputted by Star. While you can download the software locally following these instructions, it is also possible to run it from SharePoint, assuming SharePoint is mounted to your computer's file explorer.

• Periview Introduction and Walkthrough