ScriptAero

CFD Queue Processor

An automated queue management system for CFD (Computational Fluid Dynamics) simulations. This script monitors a job queue and executes CFD simulations sequentially based on priority.

Features

• Priority-based execution: Jobs are processed in order of priority (lower numbers = higher priority)
• Automatic folder management: Creates and manages queue, running, and completed job directories
• Sequential processing: Ensures only one simulation runs at a time to optimize resource usage
• Error handling: Automatically handles cases where simulation directories don't exist
• Real-time monitoring: Continuously monitors the queue for new jobs

Directory Structure

The script automatically creates and manages the following directories:

project/
├── queue_processor.sh
├── queue/          # Pending jobs waiting to be executed
├── running/        # Currently executing job
└── done/           # Completed jobs (successful or failed)

Job File Format

Each job file in the queue/ directory must:

• Have a .job extension
• Contain exactly 4 lines with the following information:

[PRIORITY]
[CASE_DIRECTORY_NAME]
[COMMAND_TO_EXECUTE]
[DESCRIPTION]

Job File Example

File: queue/turbulent_flow.job

1
airfoil_case
Allrun
Turbulent flow simulation around NACA 0012 airfoil

Field Descriptions

Field	Description	Example
Priority	Integer value (lower = higher priority)	1, 2, 10
Case Directory	Name of the CFD case folder (without path)	airfoil_case
Command	Script or command to execute	Allrun, ./run_simulation.sh
Description	Human-readable description of the simulation	"Turbulent flow analysis"

Usage

1. Configuration

Before running the script, update the CASES_DIR variable in queue_processor.sh to point to your CFD cases directory:

# Edit this line in the script
CASES_DIR="/path/to/your/cfd/cases"

2. Create Job Files

Create .job files in the queue/ directory following the format above.

3. Run the Queue Processor

Execute the script from the main directory:

./queue_processor.sh

The script will:

1. Create necessary directories if they don't exist
2. Monitor the queue/ folder for new jobs
3. Execute jobs sequentially based on priority
4. Move completed jobs to the done/ folder

Example Workflow

1. Create a job file:

   echo -e "2\nmixer_case\nAllrun\nMixing tank simulation" > queue/mixer_simulation.job

2. Start the queue processor:

   ./queue_processor.sh

3. Monitor progress: Check the running/ and done/ directories to track job status.

Error Handling

• If a case directory doesn't exist, the job is moved to done/ with an ERROR_ prefix
• Failed simulations are also moved to the done/ directory for review
• Check the done/ folder for any jobs that didn't complete successfully

Advanced Usage

Multiple Job Submission

Create multiple jobs with different priorities:

# High priority job
echo -e "1\ncritical_case\nAllrun\nUrgent simulation" > queue/urgent.job

# Medium priority job  
echo -e "5\nstandard_case\nAllrun\nStandard analysis" > queue/standard.job

# Low priority job
echo -e "10\ntest_case\nAllrun\nTest simulation" > queue/test.job

Custom Commands

You can use any executable command or script:

echo -e "3\ncomplex_case\n./custom_solver.sh\nCustom solver execution" > queue/custom.job

Notes

• Single execution: Only one job runs at a time to prevent resource conflicts
• Continuous monitoring: The script runs continuously until manually stopped
• Case sensitivity: Ensure case directory names match exactly
• Permissions: Make sure the script has execute permissions (chmod +x queue_processor.sh)

Troubleshooting

Common Issues

1. Script won't start: Check execute permissions

   chmod +x queue_processor.sh

2. Jobs fail immediately: Verify CASES_DIR path is correct

3. Case not found errors: Ensure case directory names in job files match actual directory names

4. Jobs don't start: Check job file format (must have exactly 4 lines)

Stopping the Queue Processor

To stop the queue processor, use Ctrl+C in the terminal where it's running.

Requirements

• Bash shell
• Read/write permissions in the working directory
• CFD simulation software (OpenFOAM, etc.) properly installed and configured