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

Author(s):  
Sivapalan Senthooran ◽  
Bernd Crouse ◽  
Ganapathi Balasubramanian ◽  
David Freed ◽  
Swen Noelting ◽  
...  

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.

Author(s):  
Sandra Velarde-Sua´rez ◽  
Rafael Ballesteros-Tajadura ◽  
Juan Pablo Hurtado-Cruz ◽  
Carlos Santolaria-Morros

In this work, a numerical code has been applied in order to obtain the wall pressure fluctuations at the volute of an industrial centrifugal fan. The numerical results have been contrasted using previous experimental investigations carried out in the same machine. A three-dimensional numerical simulation of the complete unsteady flow on the whole impeller-volute configuration has been carried out using the computational fluid dynamics code FLUENT®. This code has been employed to calculate the time-dependent pressure both in the impeller and in the volute. In this way, the pressure fluctuations in some locations over the volute wall have been obtained. The power spectra of these fluctuations have been calculated, showing an important peak at the blade passing frequency. The amplitude of this peak presents the highest values near the volute tongue, but the spatial pattern over the volute extension is different depending on the operating conditions. The code has successfully simulated the volute pressure fluctuations due to the aerodynamic field, capturing the main flow phenomena such as the jet-wake effects and the impeller-volute interaction.


Author(s):  
M. P. Norton ◽  
A. Pruiti

Abstract This paper addresses the issue of quantifying the internal noise levels/wall pressure fluctuations in industrial gas pipelines. This quantification of internal noise levels/wall pressure fluctuations allows for external noise radiation from pipelines to be specified in absolute levels via appropriate noise prediction models. Semi-empirical prediction models based upon (i) estimated vibration levels and radiation ratios, (ii) semi-empirical transmission loss models, and (iii) statistical energy analysis models have already been reported on by Norton and Pruiti 1,3 and are not reported on here.


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