Research On Aerodynamic Characteristics Of Non-Smooth Surface Vehicle Based On Experimental Design

With the increasing shortage of automobile consumption,the problem of oil shortage is becoming more and more serious.The problem of automobile drag reduction needs to be solved urgently.In recent years,the in-depth study of bionic non-smooth surface drag reduction and the practical application of bionic non-smooth surface drag reduction in the automotive industry have helped.To solve the bottleneck of current automotive aerodynamic drag reduction.In this paper,the computational fluid dynamics method is used to simulate the standard MIRA step back smooth model.The feasibility of the wind tunnel test data verification simulation scheme is compared.The influence of the non-smooth surface structure on the external flow field is analyzed.The non-smooth surface is verified.Correlation theory of drag reduction;design orthogonal test,analyze the influence of various factors of non-smooth surface structure on drag reduction effect,and evaluate the improvement of aerodynamic characteristics of non-smooth surface vehicles.The main work of this paper is as follows:Firstly,The numerical simulation method of computational fluid dynamics is introduced.The geometric model and calculation domain of standard MIRA step back model are established by using UG software.The mesh is solved by ANSYS software and discretely solved.The test result data of famous wind tunnel laboratory at home and abroad are compared.Verify the feasibility of the simulation calculation scheme.Secondly,the successful application examples of bionic non-smooth surfaces(like shark skin swimsuit,golf ball and FAW-Volkswagen Golf 6)and two examples of real-life tests on non-smooth surface cars at home and abroad are introduced.The structure of the non-smooth unit is designed from the aspects of shape,arrangement,size and distribution position.The MIRA step back model with different non-smooth surface structures is numerically simulated,and the smooth model is compared to the non-smooth model.The improvement of the flow field verifies the non-smooth surface related drag reduction theory.Finally,The orthogonal test was used to design the orthogonal test.The orthogonal test ? analysis showed that the primary and secondary influencing factors were C depth,D vertical and horizontal spacing,B speed,A arrangement and the optimal combined drag reduction rate was 4.5977%.In the design of concave non-smooth surface structure When first,the pit depth and spacing should be determined.The arrangement should be rectangular and rhombic.The orthogonal test? analysis shows that the primary and secondary influencing factors are E distribution,G depth,F shape,H spacing,and optimal combination reduction.The resistivity is 4.5037%.When considering the non-smooth surface structure of different shapes and distribution positions,the distribution position and depth of the non-smooth unit are considered first,and then the shape is determined.The orthogonal test ? analysis shows that the primary and secondary influencing factors are J velocity.I angle,K depth,L spacing,optimal combination drag reduction rate is 5.058%.When designing the non-smooth surface structure of the triangular groove on the rear of the car body,the angle and depth of the groove are the first consideration,and the non-smooth car is evaluated by the fuel economy of the car.