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Wind tunnel testing of reduced-scale models is a valuable tool for aerodynamic development during the early stages of a new vehicle program, when basic design themes are being evaluated. Both full-and reduced-scale testing have been conducted for many years at the General Motors Aerodynamics Laboratory (GMAL), but with increased emphasis on aerodynamic drag reduction, it was necessary to identify additional facilities to provide increased test capacity. With vehicle development distributed among engineering teams around the world, it was also necessary to identify facilities local to those teams, to support their work. This paper describes a cooperative effort to determine the correlation among five wind tunnels: GMAL, the Glenn L.

A numerical and experimental investigation was undertaken to assess the accuracy and sensitivity of a commercial CFD code when predicting the effect of changes to a car fascia on radiator airflow. The Fluent CFD software program was used to model the external and underhood airflow for the front half of a car allowing the mass flow rate of air through the radiator to be calculated. These CFD predictions were compared with experimental measurements of radiator Specific Dissipation (SD) made after CFD predictions were completed. Twenty-two cases were run with five different fascias possessing air inlets that varied in size and shape. The experimental and numerical results obtained showed a 98.4% correlation coefficient with standard deviation of 2.1% on the difference between the techniques and a prediction interval of ±4.2%. Fourteen of the twenty-two cases were ranked correctly giving a Spearman Rank Coefficient of 0.992.