City Car Drag Reduction by means of Flow Control Devices

In the past few decades, the automotive industry saw the development of several environment-friendly technologies, as high efficiency engines, lightweight materials, and low-rolling-resistance tires. Car body styling, together with aerodynamics, play an important role in resolving environmental issues by reducing drag force, which results in high fuel efficiency and lower energy requirements. The main objective of this study is the reduction of the aerodynamic resistance of a city-car prototype by means of flow control devices (air blow and air relief) located into the wheel arches. This work starts from the wind tunnel experimental tests of the baseline version of the XAM 2.0 vehicle, then, dedicated ducts are implemented into the model in order to reduce the turbulence of the front wheel well and the air-flow defection at the end of the sides of the car body. A CFD analysis is carried out in order to assess the effects of the introduced modifications: car shape is varied by CAS, for every modification CFD calculations are performed. A correlation between wind tunnel and CFD results is carried out validating the drag optimization, demonstrating the predictive capabilities of CFD analysis and a record-breaking drag coefficient.