Simulation and Design of Automobile Sunroof Buffeting Noise Control

Abstract

This paper presents the success story of an application of Computational Fluid Dynamics (CFD) analysis for automotive sunroof buffeting simulation and noise control design. Computational analyses of flow over an open sunroof of a car are performed to study the buffeting phenomenon and to determine the buffeting noise magnitude and frequency. Computations are performed for sunroofs with two types of buffeting noise control mechanisms. Numerical predictions are compared with the wind tunnel measurements. It is shown that CFD analysis has great potential for sunroof design and development

Wind loads on ground-based telescopes

“…28), which is influenced by the vented area. 6 The amplitude is also influenced by any external structure of the dome, which can affect the boundary layer thickness or the shear layer spanwise vorticity distribution (e.g., by introducing streamwise vorticity 29 ). Finally, the net effect on the mirrors results from the differential pressure across them.…”

Measurement of the sunroof buffeting noise with an automatic deflector-traversing device

“…Recently, computational methods that simulate the threedimensional flows around a vehicle and aeroacoustic responses inside the car cabin for a model vehicle in a virtual wind tunnel have drawn attention (e.g., Bernd et al 2009;Islam et al 2008; Karbon and Singh 2002). Three-dimensional shapes of a deflector and the roof near the deflector can be specified in detail, and the sound-pressure spectrum inside the car cabin can be calculated by using commercialized codes, given a mean flow free-stream velocity around the vehicle.…”

Deflated preconditioned conjugate gradient solvers for the Pressure–Poisson equation

“…Detailed comparison to experiments, mesh refinement studies, etc. of the basic scheme may be found in [24,41,11,19,18,20]. In all cases diagonal preconditioning was used in the isotropic mesh regions, while linelet preconditioning [32,40] was used for the highly anisotropic mesh regions (boundary layer grid regions).…”

“…ð2Þ where q; v; p; l denote the density, velocity, pressure and viscosity of the fluid, are based on so-called projection techniques, whereby the advancement of the flowfield in time is split into the following three substeps [22,2,23,3,32,15,1,17,37,13,24,8,41,11,19,18,20,40,[25][26][27][28]:…”