Lyftkraftsberäkning för vingprofiler

Virvelpanelmetoden

The problem presented in this report is that of finding a method to calculate the lift force from a single-element airfoil of arbitrary shape. A number of restrictions are used in order to simplify calculations while retaining reasonable accuracy. The problem is solved for the two-dimensional case only and no finite-wing effects are taken into account. Furthermore, inviscid and incompressible flow is assumed. The method used to solve the problem is the vortex panel method, with vortex singularities distributed over simplified airfoil geometry. The resulting velocities are then used to calculate the pressure distribution and lift of the airfoil.Comparison with wind tunnel tests and data from commercial software show the limits of the developed program. There is a good agreement between experimental- and calculated values up until the angle of attack where the airfoil stalls, after which the program cannot predict the value of the lift coefficient. The program should therefore not be used to analyze such conditions if correct results are to be obtained, but rather only be used for relatively small angles of attack where the airfoil does not stall.