Qualitative assessment of the bi-stable states in the wake of a finite-width double backward facing step
Journal article, 2019

The flow past a simplified frigate shape model which is analogous to a finite-width double backward facing step is investigated numerically using well-resolved large eddy simulations at Re≃8×104. The geometric configuration of this model permits the occurrence of bi-stable flow states, with an asymmetrical flow topology being observed in the lateral midplane behind each step. In each flow state, the flow at the top step is anti-symmetrical to that observed on the bottom step, and the two flow states are anti-symmetrical to each other. Furthermore, incorporating a base cavity on the top step leads to the suppression of the asymmetrical flow topology on both the steps. The recirculation bubble formed by the downwash at each step is elongated when the base cavity is used, as compared to that observed in either of the two flow states, resulting in a decrease of the drag coefficient. In each of the two flow states, the unequal strength of the streamwise vortices close to the lateral edgeson the top step has been identified as the likely cause of the asymmetrical flow on the bottom step.



Anirudh Narayan Rao

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Jie Zhang

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Guglielmo Minelli

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Branislav Basara

Chalmers, Mechanics and Maritime Sciences

Sinisa Krajnovic

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Journal of Wind Engineering and Industrial Aerodynamics

0167-6105 (ISSN)

Vol. 186 241-249

Active flow control for reduced resistance of trains, trucks, and ships

Swedish Energy Agency, 2016-12-01 -- 2018-08-31.

Driving Forces

Sustainable development

Areas of Advance


Subject Categories

Applied Mechanics

Fluid Mechanics and Acoustics


Basic sciences


C3SE (Chalmers Centre for Computational Science and Engineering)



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