Determination of Streamline Geometry and Equivalent Radius over Arbitrary Bodies with Application to Three-Dimensional Drag Problem

摘要

An exact method has been developed for determining the streamline geometry and equivalent radius over general three-dimensional bodies. This method requires knowledge of either a theoretical or experimental surface inviscid pressure distribution. The full inviscid momentum equations, written in nonorthogonal curvilinear coordinates, are reduced to a set of three first-order ordinary differential equations for determining the streamline geometry. Based on analytical relationships among coordinate variables and the streamline direction, two additional first-order equations are derived for calculating the equivalent radius. Numerical examples, which include an elliptic paraboloid and a wing-fuselage-nacelle configuration, have been considered. Calculated streamline pattern exhibits correct trend, although no comparison has been made because of lack of available data. Application of the method to three-dimensional drag problems has been demonstrated. In addition to providing the correct streamline geometry for obtaining the skin friction via the axisymmetric analogue, numerical results show that the method is capable of determining the three-dimensional flow separation associated with the free-vortex layer for evaluating the interference drag. (Author)