Research On The Effect Of Aerodynamic Noise Reduction By Bionic Modeling Around A-pillar And Side-view Mirror

As we all know, exterior aerodynamic noise generated by a high speeding car affects drivers and passengers’ comfort. Thus, how to control and reduce the aerodynamic noise has become a significant way to improve the vehicle ride comfort. By means of experiments and simulation analysis, we found the serious separation and turbulence when air flows through the area between A-pillar and side-view mirror. There have been some aerodynamic noise studies on side-view mirror or A-pillar at home and abroad. But the researches on the entire A-pillar and side-view mirror area is still tiny, especially in bionic noise reduction researches are even fewer. Accordingly, this issue combined with the principle of bionics, applied bionic modeling in A-pillar and side-view mirror area, used CFD numerical simulation method to study the influence mechanism of flow field and sound field.Firstly, the aerodynamic noise and bionics theory have been learned through extensively reading the aerodynamic noise of the related literature at home and abroad.Then the task was verified by the subject of CFD simulation method. The oil flow was got through the flow chart of the vehicle side window surface by using the experimental method. And the pressure coefficient on the side window surface was measured by using pressure coefficient experiment. The simulation model and simulate wind tunnel model of the SUV models were created, steady state and transient simulations were made to analyze the flow field and the sound field around A-pillar and side-view mirror comparing with the wind tunnel test results to verify the reliability and accuracy of the CFD method.With National Natural Science Foundation of China(Analysis and control of car interior noise based on bionic outside styling),the research about the bionic aerodynamic noise reduction of the field around A-pillar and side-view mirror of one SUV model was conducted. The six bionic models were established to have numerical simulations bycreating bionic bumps and potholes in the A-pillar, side-view mirror and the whole area.Model 1 was chosen to have analysis of the flow field and pressure field. It was found that the bionic models have certain effect on improving the flow filed through the analysis of the flow field by three typical planes. Therefore, it was predicted that bionic model also will help reduce aerodynamic noise in the region. It revealed that six bionic models have the effects of reducing the sound pressure in the side window through comparisons of the bionic model and the original in 1/3 octave sound pressure level curve and the total sound pressure level of the side window monitoring points. To further explore the bionic structural unit,distribution location, and size with the best noise reduction, the comprehensive analysis and judgment was conducted by orthogonal design. The optimum bionic noise reduction scheme was obtained by the each factor of KI values.Thus, it will help to improve the flow field and sound field on the surface of the side window, and control vehicle aerodynamic noise by using bionic bumps and potholes models in the A-pillar and side-view mirror area. Research on this subject will provide some guidance and reference on the following bionic aerodynamic noise reduction.