The Research Of The Bionic Non-smooth Structure For The Cavity Aerodynamic Noise Reduction

With the continuous development of road projects and the further improve toautomotive technology,the speed of automotive vehicle has been continuously increased, thecar’s comfort and safety also have been higher demand. In particular the aerodynamic noise,it will be obviously increased as the speed increase. Meanwhile, the aerodynamic noise is avery important automotive comfort factor. In order to meet the increase for people’s comfortand speed requirements, the study of aerodynamic noise reduction is very meaningful.In this paper, the study is for the automotive and high-speed trains that the aerodynamicnoise generated significant.The study selected the typical cavity model M219model as abasis.The maximum noise of the basis model and the flow inside the cavity can be obtainedthrough the numerical simulation. On this basis, this paper using the engineering bionicsmethods to select the bionic non-smooth structure. Mainly through the following two ways:one is selecting the known bionic non-smooth structure from the reference literature whichhas the very good effect on the aerodynamic flow field of the bionic non-smooth structure,such as the bionic v-shaped non-smooth structure and the bionics hemispherical structure;The second is using the method of engineering bionics to select the structure that can realizethe improvement of the cavity flow field, which is according to the analysis for the cavityinside flow and cavity aerodynamic noise principle, such as triangle structure and arcstructure. In order to get the optimized plan for the cavity aerodynamic noise reduction, forthe same bionic non-smooth structure,it considers the position of the structure, mainly on thefront of the cavity and the bottom of the cavity and the after of the cavity. In the study onthe location of the process, this paper considered the different between the single factor andmultiple factors on aerodynamic noise reduction effect. In addition, this paper also considersthe bionic non-smooth structure size for the cavity aerodynamic noise reduction effect. Inaddition, for different bionic non-smooth structure, this paper also considers the impact onaerodynamic noise reduction effect between each other. For these optimization models, this paper applied the numerical simulation calculationmethod for related research. Through the Star-CCM software,it selects the LES-Fw-Hhybrid simulation method, which can get the sound pressure level curve of the optimizationstructures, and then can get the structure which has the best effect. And through the analysisand study of the relevant results, this paper get the bionic non-smooth structure noisereduction mechanism.This article through to the optimization model for numerical simulation analysis foundthat the bionic non-smooth structure can improve the flow in the cavity, and thus can beimplemented on aerodynamic noise, the influence can get the cavity noise reduction. Thispaper selected the bionic non-smooth structure mostly can gain good noise reduction effecton the cavity aerodynamic noise, there are a lot of optimization of structure can achieve7db.And through the analysis of the optimization of the structure’s post-processing results, thispaper not only won the location and size of the bionic non-smooth structure on the influenceof the noise reduction effect, but also through the establishment of comprehensiveoptimization model, obtained the principle of different bionic non-smooth structurecomprehensive noise reduction...