DroneWISP (Wind Simulation and Prediction)

DroneWISP, or WISP for short, is a project that aims to simulate wind conditions for a given geometry and predict the wind velocity field using a PINN model.

(DroneWISP was previously known as RWDS, or Real Wind Drone Sim (RWDS), but was renamed to better reflect the project's goals.)

DRV, or Drone Req Validator, is a project that aims to streamline the process of validating the requirements of a drone software system. available at here

This project uses OpenFoam to simulate realist wind conditions for a given geometry. Also propose a PINN model to predict the wind velocity field in the given geometry.

Requirements

• Linux or WSL (WSL preferred)
• OpenFoam 10
• ParaView (optional, for visualization)
  • WSL users: Windows ParaView is recommended (see setup below)

Hardware suggestion

• 6+ cores CPU
• 8GB+ RAM
• 20GB+ available storage

Port reservation

• DRV REST: port 5000
• WISP REST: port 5001
• WISP UDP inbound: port 3001
• UE UDP inbound port: 8008
• UE UDP outbound target port: 3001

Getting Started

install openfoam on WSL or Linux

install linux subsystem, ignore if you are using linux natively

wsl --install

Distributor ID: Ubuntu Description: Ubuntu 22.04.1 LTS Release: 22.04 Codename: jammy

After installing WSL, open the terminal and run setup.sh

sudo bash setup.sh

Verify the installation by running the following command

foamVersion

Should return

OpenFOAM 10

If that didn't work, follow the following steps to install OpenFoam 10 on WSL manually

sudo sh -c "wget -O - http://dl.openfoam.org/gpg.key | apt-key add -"
sudo add-apt-repository http://dl.openfoam.org/ubuntu
sudo apt-get update
sudo apt-get install openfoam10
sudo apt-get install --only-upgrade openfoam10

next add the following line to the end of file .bashrc

source /opt/openfoam10/etc/bashrc

or run the following command

echo "source /opt/openfoam10/etc/bashrc" >> ~/.bashrc

source the new bashrc file

source ~/.bashrc

Python virtual environment

cd python
python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt

install openfoam on windows natively

NOT SUPPORTED

install openfoam on mac

Docker is recommended for Mac users.

WISP backend on docker

build the docker image

cd python
docker build -t wisp_server .

run the docker image (assume you are in python directory)

docker compose up

Workflow Runner batch interface

Use compose.workflow-runner.yaml to run a one-shot CFD job that accepts an STL terrain, one simulation config JSON, and a target CSV path.

Local example:

bash run_wr_job.sh \
  --stl /home/bohanzhang/DroneWISP/4drone_Test_site_V36_mono_smooth.stl \
  --config /home/bohanzhang/DroneWISP/wr_examples/sim_config_3_drone_new.json \
  --output /home/bohanzhang/DroneWISP/out/wind.csv

The runner reads wind definitions from the single config file, using environment.wind.sources in the current schema. The older environment.wind array remains supported.

Compose contract:

• WR_INPUT_STL_DIR: host directory that contains the STL file
• WR_INPUT_STL_FILE: STL basename inside that directory
• WR_INPUT_CONFIG_DIR: host directory that contains the simulation config JSON
• WR_INPUT_CONFIG_FILE: config filename inside that directory
• WR_OUTPUT_DIR: host directory where the merged CSV should be written
• WR_OUTPUT_FILE: output CSV basename

Current wind config shape:

• environment.wind.sources: array of wind source objects
• environment.wind.height_cells: integer number of CFD cells in the vertical direction, defaults to 10
• environment.wind.scale: uniform mesh scale factor in (0, 1], defaults to 1.0
• environment.origin.radius: region radius, unchanged from the simulation config

Multi-source wind handling:

• wind vectors are averaged component-wise
• the merged run is treated as Turbulent Wind if any source is turbulent
• fluctuation_percentage is taken as the maximum source value when turbulence is enabled

Notes:

• the exported CSV contains only the final time step with columns x,y,z,u,v,w
• wind.scale controls mesh scaling and therefore the horizontal CFD cell count
• there is no hardcoded maximum effective x or y cell count in the runner
• wind.height_cells directly controls the CFD z cell count and is not multiplied by wind.scale
• the solver adds a small fixed clearance around the STL, so exported coordinates can extend slightly beyond the STL extents after inverse scaling
• the WR-side input STL is expected to be box-like in most runs, with z being the least predictable dimension

Directory Structure

all OpenFOAM research scenarios are in the run directory

cd run

detailed description of each example is in the readme.md file in each directory

In general, run the following command to run the simulation

cd run
cd {example directory}
bash ./Allrun

Python entry points

WISP

start WISP side flask server: python3 cfd_server.py -h "0.0.0.0" -p 5001

PINN

preprocess velocity csv: auto_preprocess_all_for_sim.py, auto_preprocess_all_for_train.py. for sim uses weak preprocessing, for train uses strong preprocessing.

prepare training data: pinn/prepare_training_dataset.py

train the model: pinn/dnn_train.py

test the model: pinn/dnn_test.py

How to use ParaView

Setting up Windows ParaView for WSL (Recommended)

If you're using WSL and have ParaView installed on Windows, you can configure the system to use Windows ParaView instead of the WSL version. This avoids segfault issues with WSL ParaView and provides better performance.

Run the setup script from the main directory:

cd /path/to/DroneWISP
bash ./setup_paraview_windows.sh

This script will:

• Configure your shell to use Windows ParaView (G:\ParaView 5.13.2\bin\paraview.exe) by default
• Automatically convert WSL paths to Windows network paths
• Fall back to WSL paraFoam if Windows ParaView is not found

After running the script, either:

• Open a new terminal window, or
• Run source ~/.bashrc in your current terminal

Note: If your ParaView installation is in a different location, edit setup_paraview_windows.sh and update the PARAVIEW_EXE path.

Visualizing the results

To visualize the results of the simulation, you can use ParaView.

cd run
cd {example directory}
# Assuming you have already run the simulation
paraFoam

Since all Allrun scripts create an empty results.foam file, when you run paraFoam under a case directory, it will open the case in ParaView. But the results will not be visible, you need to change the view option to display the U, p, and other fields.

click on this bar and select the fields you want to display. U in this case.

now it will display the velocity field from top-down view, to see the inside of the geometry, you can use the clip filter.

to view the result at a different time, you can use the time slider at the top of the window.

The resulting visualization looks like this

Saving the results

You can save each wind velocity field as a .csv file by using paraView, or use openFoam's built-in command

postProcess -func writeCellCentres

to postprocess the results by export each cell's center to a C file. the index of C will bijectionally map to the values in the U file in each time step folder.

Or, alternatively, you can use the paraView:

This will save all the wind velocity field and cell coordinate at each time step as a .csv file in the postProcessing folder in the case directory.

Known Issues

Parallel computing issue

If your CPU has less than 6 cores, you need to change the runParallel to runApplication in the Allrun file in each example directory, otherwise the simulation may not run.

Or change your available cores in the decomposeParDict file in the system folder in each example directory by changing numberOfSubdomains 6 to your available cores.

Storage issue

microsoft/WSL#4699

If you are using WSL, the storage is limited to the 100GB, and once allocated, it cannot be freed. to free up the storage after simulating large cases, we need to delete the old cases to free up the storage for windows.

First locate the WSL image in the windows file system it should be in the following directory

C:\Users\{username}\AppData\Local\Packages\CanonicalGroupLimited.Ubunto{hash}\LocalState\ext4.vhdx

Then free up the storage by optimizing the image

wsl --shutdown
optimize-vhd -Path {path to ext4.vhdx} -Mode full

ParaView cannot be opened

If you cannot open ParaView using the command paraFoam:

1. WSL users with segfault issues: Use the Windows ParaView setup script (see "Setting up Windows ParaView for WSL" above). The WSL version of ParaView may segfault due to OpenGL issues.

2. Unusual folder names: Sometimes it's because of unusual folder names in the case folder. Delete any folders that are not the default OpenFOAM folder names and try again.

3. results.foam file issues: If OpenFOAM aborts with "invalid fileName results.foam", ensure the results.foam file is removed before running simulations. The Allclean script should handle this automatically.

Allrun and Allclean cannot be executed

if you see

./Allclean: line 3: $'\r': command not found

It is because the file is not in the correct format, change the file line separator to LF using any text editor.

IMPORTANT: if you already ran the Allrun script in CRLF format, there will be a results.foam file with LF at the end of the file name, and it will cause OpenFoam to crash. Just remove it and run the Allrun script again in LF format.