Aerodynamics and thermal management of road vehicles

NAISS 2023/3-9


NAISS Large Compute

Principal Investigator:

Simone Sebben


Chalmers tekniska högskola

Start Date:


End Date:


Primary Classification:

20306: Fluid Mechanics and Acoustics



The energy efficiency of road vehicles is central for the creation of a sustainable and modern society. In this effort, the aerodynamic drag and the thermal efficiency of systems and components are fundamental parameters to optimize since they have a direct influence in the green gas house emissions and the drive range of vehicles. 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 (negative) effect on the drag and thermal behaviour of vehicles. The Road Vehicle Aerodynamics & Thermal Management 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 based on the use of Delayed Detached Eddy Simulation (DDES) on detailed geometries, often in full-scale, and at realistic 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. Over the past years, our research projects have used approximately 700 kCPUh/month. This has been possible using our allocation with the NAISS and an availability of resources at our main industrial partners. In aerodynamics, the group’s focus has been in two major areas of potential drag reduction: (1) the vehicle’s rear wake, and (2) the flow around wheels. In the past years, we have increased our research portfolio in thermal management (TM), particularly for Battery Electric Vehicles (BEVs). We have close collaboration with the Swedish automotive industry (Volvo Cars, Volvo AB, Scania, and CVET), with KTH, Politecnico di Milano, and internally at Chalmers. We collaborate also with software companies such asSIEMENS and GAMMA Technologies. Our activities are financially supported by the Swedish automotive industry, the Swedish Energy Agency, and the Chalmers Areas of Advance: Transport and Energy.