Date Approved


Graduate Degree Type


Degree Name

Engineering (M.S.E.)

Degree Program

School of Engineering

First Advisor

Dr. Wael Mokhtar

Second Advisor

Dr. Brent Nowak

Third Advisor

Dr. Mehmet Sozen

Academic Year



The focus of the study is to explore aerodynamic aspects of cooling airflow. As a result of this study, an efficient multi-domain aero-thermal model was developed to analyze the cooling drag of a generic passenger vehicle. Cooling drag is described as the additional force that the production vehicle has to overcome while moving in comparison to the force if all the openings were closed. Though this model was developed based on the sedan class vehicle, the applied methodology could be generalized for other ground vehicle types. As a part of the presented model, a unique simplified geometric model is developed around manufacturers’ specifications to closely mimic the production vehicles. The behavior of overall drag and cooling drag were analyzed with respect to vehicle speed, coolant flow rate in the radiator and rotation speed of the radiator fan. Consequently, a simplified radiator model was designed to accommodate the multi-domain CFD modeling instead of placing a porous medium to provide flow impedance. Obtained results were compared with published reports for similar class vehicles and were validated by the grid independence tests and a wind tunnel test. The model developed in this study can act as a starting point to investigate cooling drag relations with other variables such as inlet-outlet ratio, placement of engine bay components and so on.