Aerodynamic analysis of airfoil in steady and unsteady motion

Abstract

In this paper, several basic methods for solving the wing force are introduced, namely: arranging constant vortices on the surface, linear vortices, arranging sources and sinks on the surface, and arranging vortex systems on the camber. The focus is on the last method. For thinner airfoils, the block form has a greater impact on the results; while for thicker symmetrical airfoils, the block form has little effect on the results. The results can be more accurate if the number of blocks is appropriately increased. The distribution vortices with higher order should be used on the camber surface, such as the plate vortex system and linear vortex system. Moreover, the force of the unsteady motion wing is also discussed, and the method of arranging the source and sink on the surface of the wing and the vortex system on the camber is used. For the wing with unsteady motion, the Kutta condition and the wake vortex system should be dealt with. Since the square term of the velocity term is included, the Kutta condition with equal trailing edge pressure cannot be directly adopted, and it needs to be improved. Regarding the treatment of the wake vortex, the calculation results show that the first free vortex adopts the vortex model, and the result is better. For the same airfoil, the calculation results are not very different under different time steps. Therefore, in order to improve the calculation efficiency, it is appropriate to consider increasing the time step.