Shape Optimization Design Method Of RV Based On Feature-kept Morphing Design

Automotive aerodynamics is the key to the development of automobile technology.It plays an important role in areas such as energy, transportation, the protection of the environment. Aerodynamic characteristic has a direct impact on automobile economy, power performance and maneuverability. Now the domestic research mainly focus on drag reduction and energy saving of the cars and trucks. There are few studies on the wind resistance coefficient of the RV (Recreational Vehicle). The RV needs a bigger size than others. That is dislike a normal car body and windward area is larger, causing the vehicle aerodynamic performance is poorer and aerodynamic drag is larger. At the same time, lift and trim moment will influence the vehicle steering stability. In addition, with the development of tourism, the China’s RV market gradually rised. Its shape also shows diversity, therefore, changing the RV’s shape needs to meet aesthetic, for example some important characteristics unchanged. Thus, through the method of feature-kept morphing, Changing the appearance of the RV is of great significance to study the aerodynamic characteristics.Considering the above reasons, in this paper, the main work include:first, getting point cloud data by ATOS three-dimensional scanner and establishing CAD model by reverse engineering of C ATI A. Then, the results of numerical simulation will be analysed to get the location that need to be changed.The traditional process of external flow field research includes mathematical modeling, model meshing, boundary processing and calculation.It will cost too much time to analysis,if follows the traditional process.So,using the grid deformation software in meshing is a effective way to save calculation time in this paper.Meanwhile,the "minimum rigid body displacement method" is to ensure characteristic line of RV unchanged.Integrated SCULPTOR, ICEM and FLUENT software on ISIGHT platform to build a set of effective procedures to complete the DOE test to obtain sample data.In this paper, the drag force, lift force and lateral force coefficient are selected as the optimization objective and using the approximate model to optimization.During the optimization process, the long iteration time is solved,at the same time,the key feature is kept unchanged. The correctness and practicability of the method is verified through the simulation.It also has guiding significance to modeling optimization in the future.