2차원 날개 단면 주위의 정상유동해석 향상을 위한 B-spline 및 부분선형 패널법의 적용

Abstract

Panel methods have been widely used for analyzing steady flow around two-dimensional sections. Several numerical scheme for the formulation of the panel method have been used. Constant strength Panel Method(CPM) has constantly distributed singularity strength on each panel. Piecewise Linear Panel Method(Piecewise LPM) has linearly distributed dipole strength on each panel, which has continuous dipole strength between adjacent panels, while CPM hasn’t. Velocity is calculated by numerical differentiation of the potential distribution which is calculated as a solution of the panel method.

In this paper, piecewise LPM is used for the analysis, and B-spline interpolation is adopted for the representation of potential distribution and velocity is calculated by analytic differentiation the B-spline curve. Velocity can be calculated at arbitrary locations on the panel surface with improved accuracy. In the existing panel methods, calculation of velocity is possible only at the center of panel due to the application of numerical differentiation.

Calculated results for several Karman-Trefftz foil sections are given, to show the advantage of the suggested method. ‘Errors’ between the calculated and the analytic values are compared to confirm the improvement of the suggested method.