Suction control of laminar separation bubble over an airfoil at low Reynolds number

Abstract

A laminar separation bubble appears generally on the NACA2415 airfoil at low Reynolds number. In this paper, suction control of the laminar separation bubble over the NACA2415 airfoil at low Reynolds number are simulated. The effects of suction control on the flow field and the aerodynamic characteristics of the airfoil are focused on at different angles of attack. Numerical simulations show that employing the γ-Re_θt transition model coupling the k–ω shear stress transport turbulence model can predict the laminar separation bubbles accurately. The results indicate that suction control can delay the transition, decrease the velocity gradient of the boundary layer and inhibit the production of the separation bubble. The effect of the suction control becomes better with the suction location getting closer to the separation bubble and the suction speed (the suction gas speed of suction hole) getting faster. The figure of merit is introduced to evaluate energy consumption of the suction control. In consideration of the economic effects, the suction control is suitable for the larger angle of attack situation at low Reynolds number.

Keywords

Low Reynolds number separation bubble suction control control efficiency lift-to-drag ratio

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