Boundary layer over a blunt body at low incidence with circumferential reversed flow

Abstract

This paper investigates the three-dimensional laminar boundary layer over a blunt body (a prolate spheroid) at low incidence and with reversed flow. Results reflecting the general characteristics of such a problem are presented. More significant are the features relating to the circumferential flow reversal. Some of these features confirm our early hypotheses concerning the existence of a reversed region ahead of separation and the role of the zero-cfθ line in the general context of separation in three dimensions. Other features are unexpected, including the distribution of cfμ and the shape of the separation line. Here cfθ and cfμ denote, respectively, the circumferential and meridional components of the skin friction.

Boundary layer over spinning blunt body of revolution at incidence including Magnus forces

“…• choice comes naturally from previous experience (Wang 1975) in a nonspinning case for the same body where similar reversal of the circumferential flow also occurs . The calculability of such reversed flow was rationalized , thereby using the rule of the dependence zone pertaining to three-dimensional boundary layer equations .…”

“…For the calculation of the w-velocity from the • continuity equation (Wang 1975) , the derivative , 3w/3z , at first was averag ed over corner stations (rather than approximated at a single central station as in this work) and was found to exhibit fluctuat ion , causing eventual breakdown of calcul at ion. Such difficul ty results from the difference approximat ion for the continuity equat ion and hence falls beyond the predict ion of…”

“…The finite difference schemes used in this work are those employed previously for the nonspinning case (Wang 1974a(Wang , 1975 ; they are implicit schemes of the Crank-Nicolson type . Corresponding to the dependence zones of figure 3 , three different meshes are used (figure 4).…”

Flow-Visualization of Three-Dimensional Boundary-Layer Separation on Bodies of Revolution at Incidence.

“…In some instances , the geometries that have been considered are quite simple (e.g., cones). The flow past a spheroid has been studied theoretically b~ Wang in a series of recent papers (Wang, 1970(Wang, , 1971(Wang, , 1972(Wang, , 1975(Wang, , and 1976. Iqis computations were made at Reynolds numbers low enough for the boundary layer to be laminar everywhere .…”

“…Some measurements are also available for the spheroid in the experiments of Wilson (1971). In a set of later publications , Wang ( , 1975 separation . Thus, the proposals of Maskell (1955) and Wang (1972) are verified by the present experiments .…”