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In a typical ground vehicle, airflow enters engine compartment through grille and carries heat from the engine, cabin and other auxiliaries through heat exchangers such as radiator, condenser, oil cooler and charge air cooler respectively. The amount of airflow entering the engine compartment is governed by their individual resistances, the grille and engine compartment resistances. Also, this flow adds to drag and deteriorates overall aerodynamic efficiency. It is known as cooling drag which contributes to 8 to 12 percent of overall drag. Aerodynamics and Front End Air Flow (FEAF) development happens through CFD and it demands accurate heat exchanger pressure drop data which is usually obtained from supplier at very early stages of a vehicle development. Historically, this data is found to have significant variations compared to in-house test data.

Implementing stringent emission norms and fuel economy requirement in the coming decade will be very challenging to the whole automotive industry. Aerodynamic losses contribute up to 13% to 22 % of overall fuel economy and aerodynamicists will be challenged to have optimum content on the vehicle to reduce this loss. Improving Aerodynamic performance of ground vehicles has already reached its peak and the industry is moving towards active mechanisms to improve performance. Calibrating or simulating these active mechanisms in the wind tunnel or in Computational Fluid Dynamics (CFD) would be very challenging as the model complexity increases. Computationally expensive CFD models are required to predict the transient behaviors of model complexity.