Study and Design Frontal Area of a Car to Curtail Aerodynamic Noise

Abstract

Abstract: In this field of comparative research study, comparison of two car model, a standard car and an optimized car with respect to aerodynamic analysis/aeroacoustics analysis with the help of CFD software Ansys 2019 R2 version is taken in consideration to compare the results and get to know if the optimized car model has reduction in the generation of aerodynamic noise when it travels at four different speeds (30 m/s, 40 m/s, 50m/s and 60m/s). For carried out aeroacoustics/aerodynamic noise analysis two main model are used turbulence model and an acoustics model. For turbulence model and K-epsilon model is used as it is widely used for getting turbulence generation and for acoustics model a Broadband noise model is used to generate the results through numerical simulation and data sources. First a standard sedan car is modelled in Onshape CAD tool and aeroacoustics analysis is carried out on this standard sedan car to get to know the source of aerodynamic noise. From the standard car results made changes in the sedan car geometry like giving fillets to point/sharp edges of wheel arcs, front bumper, hood-line, fender and start of roofline from A-pillar, providing under-flush, optimizing A-pillar beam and optimizing outside rear view mirror and making them fully camera integrated mirror to reduce wake. After optimizing standard geometry carried out aerodynamic analysis with the same four different speed given for standard car (30 m/s, 40m/s, 50m/s and 60 m/s). Generated contour plots and isosurface from CFX for flow characteristics and acoustic sound source with various model like Proudman’s acoustic power level in Db, Curle surface acoustic power level in decibels (dB) and also, Lilley S total noise source to show the sources of noise and how many decibels of noise is generated from those sources. Maximum of 100 decibels of noise is generated from the front bumper and a minimum of 80 decibels were monitored in the results process after comparing the results with standard car which has noise nearly 120 decibels with high fluctuations of turbulence kinetic energy and decrease in its pressure level. Keyword: Aeroacoustics, Aerodynamic noise, Aeolin sound, Fluid dynamics, NVH (noise, vibration and harshness) and CFD (computational fluid dynamics).