Regular Article

Numerical investigation of the vibration effect of a flexible membrane on the flow behaviour around a circular cylinder

¹ Unit of Computational Fluid Dynamics and Transfer Phenomena, National Engineering School of Sfax, University of Sfax, B.P. 1171, 3038 Sfax, Tunisia
² Sfax Preparatory Engineering Institute, University of Sfax, B.P. 1172, 3018 Sfax, Tunisia
³ Faculty of Sciences of Sfax, Department of Physics, University of Sfax, B.P. 1171, 3000 Sfax, Tunisia

^* e-mail: nabaouia.maktouf@gmail.com

Received: 21 November 2017
Accepted: 5 March 2018
Published online: 8 June 2018

Abstract

Active control of the flow behind a bluff body is obtained by integrating a vibrating membrane. A numerical study has been conducted to investigate the effect of the vibration of a flexible membrane, stuck to the rear side of a circular cylinder, on the global flow parameters such as the Strouhal number, the drag and lift coefficients. The shape of the membrane is evolving as a vibrating chord using a dynamic mesh. The governing equations of 2D and laminar flow have been solved using ANSYS Fluent 16.0 as a solver and the Gambit as a modeler. The motion of the membrane is managed by two parameters: frequency f and amplitude A. The effect of the flexible membrane motion is studied for the range of conditions as 0.1 Hz ≤ f ≤ 6 Hz and 5 × 10⁻⁴ m ≤ A ≤ 10⁻³ m at a fixed Reynolds number, Re = 150. Three different sizes of the flexible membrane have been studied. Results show that a beat phenomenon affects the drag coefficient. The amplitude does not affect significantly the Strouhal number as well as drag and lift coefficients. By increasing the size of the flexible membrane, we show a lift enhancement by a growth rate equal to 39.15% comparing to the uncontrolled case.