Numerical solution of unsteady flow on airfoils with local membrane in transient and laminar flows
Article history: Received 05 December 2015 Received in revised form 19 January 2016 Accepted 11 Feburary 2016 Available online 01 March 2016 Unsteady flow separation on the airfoils with local flexible membrane (LFM) has been investigated in transient and laminar flows by the finite volume element method. A unique feature of the present method compared with the common computational fluid dynamic softwares, especially ANSYS CFX, is the modification using the physical influence scheme in convection fluxes at cell surfaces. In contrary to the common softwares which use mathematical methods for discretization, this method considers the physical effects on approximation and discretization and thus increases the accuracy of solution and decreases the diffusion errors significantly. We have focused on the effects of deformation of the membrane on aerodynamic characteristics. For this purpose, first, we have solved the flow on NACA0012 airfoil in Reynolds number of 5000 and investigated the effects of local flexible membrane on aerodynamic coefficients in laminar flow. Then, we have solved the flow over LH37 airfoil in Reynolds number of 1.1x106 and studied the effects of flexible membrane on aerodynamic characteristics in transient flow. To calculate the Reynolds stress in turbulence equations, transient model has been used. According to the results, airfoil with local flexible membrane prevents flow separation, eliminates laminar separation bubble (LSB) and delays the stall. (c)2016 Iranian Society of Acoustics and Vibration, All rights reserved