ONERA's CRM WBPN database for machine learning activities, related regression challenge and first results

TL;DR

This paper introduces a CFD database for machine learning in aerodynamics, defines a regression challenge to predict pressure and friction distributions, and evaluates several ML regressors with initial promising results.

Contribution

It provides a new CFD database, formulates a regression challenge for aerodynamic prediction, and benchmarks classical ML regressors on this task.

Findings

Initial ML models show promising R^2 scores.

The database covers a wide range of flow conditions.

Benchmark results guide future ML development in aerodynamics.

Abstract

This paper presents a new Computational Fluid Dynamics database, developed at ONERA, to support the advancement of machine learning techniques for aerodynamic field prediction. It contains 468 Reynolds-Averaged Navier-Stokes simulations using the Spalart-Allmaras turbulence model, performed on the NASA/Boeing Common Research Model wing-body-pylon-nacelle configuration. The database spans a wide range of flow conditions, varying Mach number (including transonic regimes), angle of attack (capturing flow separation), and Reynolds number (based on three stagnation pressures, with one setting matching wind tunnel experiments). The quality of the database is assessed, through checking the convergence level of each computation. Based on these data, a regression challenge is defined. It consists in predicting the wall distributions of pressure and friction coefficients for unseen aerodynamic conditions. The 468 simulations are split into training and testing sets, with the training data made available publicly on the Codabench platform. The paper further evaluates several classical machine learning regressors on this task. Tested pointwise methods include Multi-Layer Perceptrons, $\lambda$-DNNs, and Decision Trees, while global methods include Multi-Layer Perceptron, k-Nearest Neighbors, Proper Orthogonal Decomposition and IsoMap. Initial performance results, using $R^2$ scores and worst relative mean absolute error metrics, are presented, offering insights into the capabilities of these techniques for the challenge and references for future work.