DrivAer Notchback

Introduction

The DrivAer is a realistic generic vehicle geometry developed by TU Munich and has become an accepted standard for automotive aerodynamic CFD correlation. The notchback variant of the DrivAer forms Case 2 of the 4th Automotive CFD Prediction Workshop (AutoCFD 4), which aims to assess the predictive capability of CFD codes for road-car geometries through mandatory geometry, boundary conditions and computational grids.

This validation case simulates the full-scale DrivAer notchback with a detailed underbody, closed cooling and static floor and wheels, matching the Pininfarina wind tunnel test conditions at a vehicle speed of 140 kph and 0° yaw. The realistic body shape exercises the solver across a wide range of flow features, from the attached boundary layers over the bonnet and roof to the separated, reattaching flow over the rear screen and boot deck that makes the notchback configuration a demanding prediction target. A comprehensive experimental data set from the Pininfarina Wind Tunnel (courtesy of Ford), including aerodynamic forces, 209 surface pressure probes, velocity profiles and flowfield measurements, is available for comparison.

Centreline Pressure Coefficient

The upper-body centreline pressure coefficient (C_p) distribution compares HiPer against the experimental measurements. The plot captures the stagnation region at the front bumper, the acceleration over the bonnet, the pressure recovery at the base of the windscreen, the strong suction at the roof leading edge and the separated flow over the rear screen and boot deck. HiPer shows good agreement with the experimental measurements along the full length of the vehicle, including the challenging notch region at the rear.