Sivapalan Senthooran

Simulation of Wall Pressure Fluctuations on Simplified Automobile Shapes Using a Lattice Based Method

A comparison of experimental data and CFD simulation results of wall pressure fluctuations on simplified geometries that generate flow structures similar to an automobile are presented. The numerical results have been obtained using the commercial software PowerFLOW 3.4p4a. The simulation kernel of this software is based on the numerical scheme known as the Lattice Boltzmann Method (LBM), combined with an RNG turbulence model. This scheme accurately captures time-dependent aerodynamic behavior of high Reynolds number flows over complex geometries, together with the acoustics. The geometries considered for this study represent the green house and the side mirror of a car. Spectral analysis is performed on the simulation data and the results are compared to the experimental data. This comparison provides good correlation between the simulation and experiment, and demonstrates the capability of this numerical scheme in predicting turbulent fluctuations due to complex flow phenomena.Copyright

Statistical Analysis of Correlation Between Simulation and Measurement of Interior Wind Noise

Aeroacoustic simulation with CFD (Computational Fluid Dynamics) generates large result datasets that need to be analyzed carefully to correlate with interior wind noise measurements. Recently, a new tool has been developed that simulates interior noise from exterior air flow by combining transient CFD for flow simulation and SEA (Statistical Energy Analysis) for vehicle structural acoustic response. Several interesting data reduction techniques have been employed to correlate dozens of separate passenger vehicle tests with the corresponding simulation results. This paper presents results of this correlation study, including statistical analysis of the resulting frequency domain comparison.Copyright

Computational Prediction of Noise Generation and Radiation from Antennas using a Lattice Boltzmann Scheme

Noise generated from isolated automobile antennas is computationally predicted and compared to experimental data. Two different antenna configurations were considered for this study. The numerical results have been obtained using the commercial software PowerFLOW 4.0a. The simulation kernel of this software is based on the numerical scheme known as the Lattice Boltzmann Method (LBM), combined with an RNG turbulence model. This scheme accurately captures time-dependent aerodynamic behavior of high Reynolds number flows over complex geometries, together with the acoustics. A hybrid approach which couples the transient aerodynamic predictions from the LBM to the Ffowcs Williams and Hawkings analogy to predict the far-field radiated sound is applied for this study. Detailed analysis was done on the simulation results to understand the influence of the antenna shapes on the characteristics of the tones generated by them. Flow visualizations were done to demonstrate the noise generation mechanism and the sound radiation pattern. Spectral analysis is performed on the simulation data captured by a microphone which is 3 inches away from the antenna and the results are compared to the experimental data. This comparison provides good correlation between the simulation and experiment, and demonstrates the capability of this numerical scheme in predicting the aerodynamic and acoustic pressure fluctuations that result in far-field noise from extruded bluff bodies.