The Collaborative Optimization Research Of The Carbody With Lower Aerodynamic Drag Characteristic And Noise Based On Feature Points

Car styling is the key factor of aerodynamic performance and sales,a good modeling is usually the fusion of aerodynamic performance andaesthetic. The aerodynamic drag characteristic and noise as the mainfeature of aerodynamic performance, is closely related to the fueleconomy and the riding comfort. As the car entered the ordinary familyand the people put forward higher requirement of automobile quality. Thelower drag and noise of the car styling has become a hotspot ofautomobile research and development at home and abroad.Previous researches mainly limited on the drag reduction of car bodyand the combination of lower drag modeling and aesthetic, while theresearch of lowering aerodynamic noise is confined to the attachments,the comprehensive characteristics of aerodynamic drag and noise has notyet been conducted in the research of car styling design. Because of thecomplex coupling relationship between drag and noise, the inconsistent ofthe two objective functions, makes the collaborative optimizationresearch of aerodynamic drag and noise having great theory significanceand utility value for the car styling.Multidisciplinary Design Optimization through fully using thesynergistic effect between different objects, to gain an overall satisfactionsolution, which has been widely concerned especially in the field ofaerospace, machinery etc. This paper is applying the MDO method to thecollaborative optimization of the aerodynamic drag characteristics andaerodynamic noise characteristics of, the main research are as follows:(1) Because the flow field is the foundation of the aerodynamic dragand noise calculation, in order to guarantee the reliability of thecollaborative optimization, this paper using MIRA, an internationalstandard model to the comparison and analysis of the reliability about thethree kinds of simulation scheme of flow field. With the applying of a realcar model, the simulation research of the drag and noise performancehave been conducted, the verification is finished by test of wind tunneland real vehicle road respectively, which makes a base for later research.(2) Based on the overall optimization point, line and plane modeling ideal, this paper proposes a converse modeling method based on featurepoints of a real car, after selecting the key factors, this paper combinedCFD simulation technology and the approximation method of RSM, toestablish the response relationship between the global dimensions and theaerodynamic drag coefficient. On this basis, the global optimization isfinished with the application of MIGA, and a model with the bestaerodynamic drag characteristics is obtained.(3) The main sound source of the body is analyzed, after identifiedthe key aerodynamic noise factor, a reliable response surface model ofaerodynamic noise is built. Based on this, the global optimization isconducted also with the application of MIGA, what’s more, the impact ofrearview mirror on the aerodynamic noise characteristics is analyzed.(4) The collaborative optimization mathematical model ofaerodynamic drag and noise is provided, the basic framework and thework flow are constructed, and with the help of the software of Isightwhich is an optimization platform, the multidisciplinary optimization ofthe car body is realized.