Development of Theoretical Method for Two-Dimensional Multi-Element Airfoil Analysis and Design. Part I: Viscous-Flow Analysis Method

摘要

A method has been developed for the analysis of arbitrary multi-element airfoils in viscous flow. The viscous solution is obtained through an inviscid analysis of an equivalent system defined from viscous considerations. An iterative procedure has been formulated to implement this analysis. The inviscid solution is obtained through a distributed singularity method. A finite-difference method is used to determine boundary-layer characteristics. Methods are included to predict laminar-flow bubbles and separation and transition points. The equivalent airfoil is defined for airfoils with attached flow as well as for airfoils with flow separation. The validity of the method is established through comparison of the predicted results with experimental data for several single- and multi-element airfoils. The comparisons show good agreement for lift coefficient and maximum lift coefficient and fair agreement for drag and pitching moment coefficients. Details of the computer program developed to implement this method are described, including input and output details, FORTRAN source deck listing, and a sample problem. (Author)