DOI: 10.5281/zenodo.13364264
title: Correlations for aerodynamic force coefficients of non-spherical particles in compressible flows

description: This repository consists of the data and exemplary python scripts for the paper "Correlations for aerodynamic force coefficients of non-spherical particles in compressible flows" by Christian Gorges, Victor Chéron, Anjali Chopra, Fabian Denner and Berend van Wachem. The data stored in this repository have the following data format:

-   .csv files consisting the raw data of the simulations used for the coefficient plots in the results' chapter of the paper   -   .py files containing python scripts serving as examples on how to use and plot the raw data of the .csv files and the correlations

The main folders of this repository are named as the non-spherical particle shapes (Oblate, Prolate, Rod-like) and a folder for the correlations. For instance, the Oblate folder contains the .csv files of all simulations of the oblate spheroid for all Reynolds numbers, Mach numbers, and angles of attack.

The correlations folder consists of temporally averaged drag, lift and hydrodynamic torque coefficients, which are written in .csv files and stored in the folder ResultsCoefficients. Python scripts used to plot the correlations are stored in the folder PythonScript.  

The naming style of the raw data files and the subfolders for each section is explained in the following:

The file names of the .csv files within the particle shape folders consist of the Reynolds number, followed by the Mach number and the angle of attack. For example "log_Re100M2_0_alpha_90.csv" consists of the data for a Reynolds number of 100, a Mach number of 2.0 and an angle of attack of 90 degrees. The content in the .csv files is the following: "%e,%e,%e,%e,%e,%e\n" which corresponds to "Physical time, lift coefficient, total drag coefficient, pressure drag coefficient, viscous drag coefficient, pitching torque coefficient". The first row in each file gives the headers of each column.

The .csv files in the Correlations/ResultsCoefficients/ folder are split per coefficient, shape, and particle Reynolds numbers, which can be identified by the name of the .csv file. For instance, the results obtained for the lift coefficient ofthe prolate spheroid particle for at a particle Reynolds numbers 100 for all orientation angles and Mach numbers are given in the file:"Prolate_100_CL.csv". In these files, the results are ordered per orientation angle (rows) and Machnumber (column). 

The python scripts have been tested with Python 3.11.5.

PlotCoefficients.py is an exemplary python script to read the .csv files and plot the aerodynamic force coefficients as it is done in the results section of the paper.

The python scripts in Correlations/PythonScript are split among three main functions in two files:- Getter (read the .csv files storing the coefficients - separate functions for the drag, lift and torque coefficients)- ManuscriptCorrelation with all the correlations derived in this work for an effective implementation in any solver, and a plotting function to have visual representation of the correlations.- generalmain (calls Getter and Plotter)

The getter is called from the generalmain.py file. (run python3 generalmain.py) so that all coefficients can be gathered in a 3D array.First dimension : Reynolds numberSecond dimension : Orientation angleThird dimension : Mach number

Additionally, the file called ManuscriptCorrelation is a script to implement the correlations discussed in the manuscript in a Lagrangian solver.

This project has received funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), grant number 447633787.