Investigation of the flow behaviour over NACA Airfoils using Subparametric Finite Element Method

Abstract

An automatic mesh generator with higher order curved triangular elements around two-dimensional airfoil designs using MATLAB code has been provided in this thesis. This work shows a valuable basis for the finite element procedures involved in evaluating aerodynamic performances. Finite element method (FEM) effectively solves many computational fluid dynamics problems around the airfoil design. Meshes have been formed on the basis of subparametric transformation created for the curved triangular elements obtained from the nodal relations of parabolic arcs. The element and nodal information gained from this discretization is useful for the numerical solutions of FEM and for the aerodynamic portrayal. It presents a refined higher order (HO) curved triangular discretization of airfoil designs namely NACA0012, NACA0015, NACA0021 and NACA0018 inscribed inside a circle. Potential flow analysis, flow transition and a numerical investigation of aerodynamic characteristics such as lift coefficient, drag coefficient, pitching moment coefficient, skin friction and the lift-to-drag ratio have been performed which provides an accurate analysis to interpret the effects of Reynolds numbers ranging from 10,000 to 10,00,000 (104 lt Re lt 106) at different angle of attacks. The implementation of the novel meshing scheme with HO elements and the numerical interpretation of intrinsic property for the airfoil design at different conditions have been carried out with MATLAB and XFLR5 software respectively. newline