COMPUTATION OF FLOW ABOUT AIRFOILS – COMPARISON OF DIFFERENT METHODOLOGIES

Resumo

The aerodynamic study of an airfoils is fundamental to analyse the behavior and geometrical characte-
ristics of a wing for prescribed flight conditions. Based on analyzes and simulations we are able to define the

variables for aerodynamic design of an aircraft. The unmanned aerial vehicle (UAV) designed for SAE Aerodesign
competition use high lift profiles for low Reynolds number flow. The viscous or inviscid flow about airfoils can
be computed using different methodologies, such as panel method or finite volume method. The main objective of
this work is to compute and compare the lift and drag coefficients as well as pressure distributions in the contour
of airfoils by calculating the inviscid and viscous flow, using a panel method and a finite volume method. For the
analysis, high lift profiles of the families NACA 4, EPPLER, GOE, CH and SELIG were selected. These classes of
airfoils have very good aerodynamic efficiency with high ratio between the lift and drag coefficients. These profiles
are highlighted by its high mean-line curvature and are used at low speeds, being indicated for the SAE Aerodesign
competition aircrafts. The criterion used to choose the airfoil was the highest lift coefficient generated in relation
to its maximum stall angle, at a number of Reynolds of cruising flight speed, that is close to the transition from
laminar boundary layer to turbulent boundary layer. The panel method analysis was performed using the XFRL5
software that uses XFOIL as source code. In the finite volume method, the Fluent code of ANSYS

R was used.
Different types of meshes, structured and unstructured, are compared and the quality parameters of the elements
generated are analyzed and presented. The pressure distributions and the lift and drag coefficient curves for the
selected aerodynamic profile are presented and compared, calculated using the panel method and the finite volume
method.