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An extensive calibration study has been initiated to assess the predictive ability of CFD (Computational Fluid Dynamics) for the aerodynamic design of automotive shapes. Several codes are being checked against a set of detailed wind tunnel measurements on ten car-like shapes. The objective is to assess the ability of numerical analysis to predict the CD (drag coefficient) influence of the rear end configuration. The study also provides a significant base of information for investigating discrepancies between predicted and measured flow fields and for assessing new numerical techniques. This technical report compares STAR-CD predictions to the wind tunnel measurements. The initial results are quite encouraging. Calculated centerline pressure distributions on the front end, underbody and floor compare well for all ten shapes. Wake flow structures are in reasonable agreement for many of the configurations. Drag, lift, and pitching moment trends follow the experimental measurements.

Automotive manufacturers are under pressure to improve the fuel consumption and emissions figures produced by standard drive cycle tests of their vehicles. Drive cycle tests, such as the New European Drive Cycle (NEDC) start with the engine and transmission cold. The fuel consumption is worse for a cold powertrain than when it is at normal operating temperatures and consequently one way of improving both fuel consumption and emissions is by heating the powertrain as quickly as possible. The PITSTOP (Powertrain Integrated Thermal Systems for Thermodynamically Optimised Performance) project brought together several companies to find ways of reducing the powertrain warm up time. Part of the project was to develop a thermal model of the engine that could both simulate the baseline powertrain and predict the potential improvements of alternative thermal management strategies.