Browse Publications Technical Papers 2011-37-0017

Numerical Comparison of Rolling Road Systems 2011-37-0017

The entire automotive industry is moving towards lower CO₂ emissions and higher energy efficiency. Especially for higher driving speeds this can be achieved by minimizing aerodynamic drag. Additionally, aerodynamic downforce is essential to maintain or even improve the handling performance of a vehicle. In order to optimize the vehicle's aerodynamic efficiency in wind tunnel tests, the boundary conditions of a vehicle driving on a road must be simulated properly. Particularly for optimizing the underbody region of a vehicle, ground simulation is an important issue in every wind tunnel. Today rolling road systems featuring one or more moving belts on the wind tunnel floor are a standard tool to simulate the complex boundary condition of a vehicle driving on the road. But generally the technical effort to measure aerodynamic forces accurately increases with improvement of the aerodynamic ground simulation.
This paper presents an attempt to evaluate the influence of different rolling road systems. The use of CFD makes it possible to investigate their influence on different types of vehicles excluding wind tunnel interference effects and independent of force measurement techniques. A numerical study with a standard passenger car and generic racing cars is presented. This study includes rolling road systems like a 5-belt, a T-belt and a single belt system as well as a new 3-belt rolling road layout.
An investigation of surface pressures, force development graphs and integral values is shown to analyze the influences of different rolling road systems. It can be concluded that, particularly concerning aerodynamic developments for the vehicle underbody, single belt systems are at least multiple partial belt systems of similar dimensions are essential to guarantee an optimal and reliable ground simulation in automotive wind tunnels.


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