The energy efficiency of road vehicles is central for the creation of a sustainable and modern society. In this effort, the aerodynamic drag is a fundamental parameter to minimize since it has a direct link to the fuel consumption and emissions. The flow around road vehicles is very complex due to the presence of three-dimensional, unsteady flow structures that are linked to regions prone to separation. These separation prone regions typically have a very large effect on the vehicles’ drags. Understanding and being able to numerically predict these time-dependent structures is essential to improve the aerodynamic performance of vehicles.
The Road Vehicle Aerodynamics Group (RVAD) at Chalmers has extensive experience with these types of flows, and works in close collaboration with the Swedish automotive industry through various research projects. To maintain, and further develop the group’s international competitiveness, availability to large computational resources is critical. The simulations conducted by the group are currently based on the use of Delayed Detached Eddy Simulation (DDES) on full-scale, detailed geometries and at high Reynolds numbers. These computations require several seconds of simulation time for meaningful averaging of the flow field. In addition, large mesh sizes are needed to adequately resolve the near wall flow, making the total process very computationally demanding.
For the past years, the group’s focus has been in two major areas of potential drag reduction: (1) active flow devices, and (2) rotating wheels. A third area of focus is on validation and optimization methods. The group also conducts research related to future transportation solutions, such as vehicles traveling in a platoon. The activities are supported by the Swedish automotive industry, the Swedish Energy Agency and the Chalmers Area of Advance Transport.