Structures of Flow Separation on a Passenger Car
Journal article, 2015

The phenomenon of three-dimensional flow separation is and has been in the focus of many researchers. An improved understanding of the physics and the driving forces is desired to be able to improve numerical simulations and to minimize aerodynamic drag over bluff bodies. To investigate the sources of separation one wants to understand what happens at the surface when the flow starts to detach and the upwelling of the streamlines becomes strong. This observation of a flow leaving the surface could be captured by investigating the limiting streamlines and surface parameters as pressure, vorticity or the shear stress. In this paper, numerical methods are used to investigate the surface pressure and flow patterns on a sedan passenger vehicle. Observed limiting streamlines are compared to the pressure distribution and their correlation is shown. For this investigation the region behind the antenna and behind the wheel arch, are pointed out and studied in detail. Besides the discussion of the correlation between limiting streamlines and the surface pressure distribution, it is discussed how the surface pressure and limiting streamline development is formed. It is shown how vortices emanating from the antenna influence the surface pressure and therefore the limiting streamline pattern. Behind the front wheel arch it is explained how the separation bubble upstream influences the development of the limiting streamlines further downstream.

Vehicle Aerodynamics

Flow Separation


Sabine Bonitz

Chalmers, Applied Mechanics, Vehicle Engineering and Autonomous Systems

Lars Larsson

Chalmers, Shipping and Marine Technology, Marine Technology

Lennart Löfdahl

Chalmers, Applied Mechanics, Vehicle Engineering and Autonomous Systems

Alexander Broniewicz

Volvo Cars

SAE International Journal of Passenger Cars - Mechanical Systems

1946-3995 (ISSN)

Vol. 8 1 177-185

Driving Forces

Sustainable development

Innovation and entrepreneurship

Areas of Advance




C3SE (Chalmers Centre for Computational Science and Engineering)

Subject Categories

Vehicle Engineering



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