The aerodynamic optimization of passenger cars has become a major task in the development process of SVW when developing cars for the Chinese market. The pressure to reduce fuel consumption and emissions is leading to aggressive targets for aerodynamic drag. Furthermore, Chinese regulations require the publication of aerodynamic drag of vehicles sold in the Chinese market.
This paper describes the approach taken by Shanghai Volkswagen (SVW) for the aerodynamic development of the New Lavida. During this project, SVW optimized its development process by extensively using CFD simulation to reduce aerodynamic drag in the very early phase of the project, i.e. the design of the upper body. Very often the interaction between styling and aerodynamics is an iterative procedure for finding a compromise between function and styling and a short response time for the aerodynamic evaluation is required. CFD turns out to be the ideal tool for collaboration between design, package, regulation and aerodynamics in this phase of the development.
In a later stage, testing in the new full scale aeroacoustic wind tunnel of the Shanghai Automotive Wind Tunnel Center (SAWTC) at Tongji University plays a more important role. Wind tunnel testing was on the one hand used to confirm the CFD results and on the other hand used for optimizing components and layout of the underbody. Such modifications do not interfere with styling and are often carried out as parameter studies which can be done very quickly in the wind tunnel once a model has been built.
The approach with significant involvement of CFD for the aerodynamic optimization of the New Lavida has enabled SVW to reach the target of 4% reduction in aerodynamic drag over the Lavida (last generation) with minimal use of physical testing in the wind tunnel.