Comparison of Large Eddy Simulation Predictions with Particle Image Velocimetry Data for the Airflow in a Generic Cabin Model

Abstract

A comparison of computational fluid dynamics (CFD) predictions and experimental data for the airflow in a generic cabin model is presented in this paper. The CFD predictions were generated using the large eddy simulation (LES) model, while the particle image velocimetry (PIV) technique was used to obtain the experimental data. A brief summary of the test setup and the experimental data are described herein. The main focus of this study is to analyze the temporal variation of the experimental data. The time series of the PIV measured velocity components with sampling frequencies of 0.1 and 5 Hz were compared with the CFD predictions, sampling at 20 Hz. Energy spectral analysis, through fast Fourier transformation (FFT) on the PIV data and their CFD counterparts, was performed and is presented in this study. By using direct comparisons of the velocity data, good agreement on the range of the velocity components was obtained at all monitoring locations, hence validating the LES predictions. A similar conclusion can be reached from the results of the energy spectral analysis. The energy-spectrum function calculated from the LES predicted velocity magnitudes has excellent correlation with the Kolmogorov spectrum law in the universal equilibrium range. For the smaller wave numbers, the PIV data taken at 0.1 Hz clearly reveal the characteristic motion of the largest eddy in the flow domain, and it correlates very well with the CFD predictions.