Experimental Comparison of the Aerodynamic Behavior of Fastback and Notchback DrivAer Models

Abstract

<div class="section abstract"><div class="htmlview paragraph">The experimental investigation was conducted with a 25%-scaled realistic car model called “DrivAer” mounted in a wind tunnel. This model includes geometric elements of a BMW 3 series and an Audi A4, accommodating modular, rear-end geometries so that it represents a generalized modern production car. The measurements were done with two different DrivAer rear end configurations (fastback and notchback) at varying side-wind conditions and a Reynolds number of up to Re=3.2·10<sup>6</sup>. An array of more than 300 pressure ports distributed over the entire rear section measured the temporal pressure distribution. Additionally, extensive flow visualizations were conducted.</div><div class="htmlview paragraph">The combination of flow visualization, and spatially and temporally resolved surface pressure measurements enables a deep insight into the flow field characteristics and underlying mechanisms. Moreover, static pressure fluctuations indicate regions with a high turbulence level due to flow separation and interaction between different vortical structures. A directional decomposition of the pressure coefficient is demonstrated and acts generally normal to the surface of the vehicle, in the drag and lift direction.</div></div>