Detailed Investigation of the Three-Dimensional Separation About a 6:1 Prolate Spheroid

Flow-Separation Lines on Axisymmetric Bodies with Tapered Tails

“…Separation on slender bodies of revolution, in particular, has been extensively investigated [5][6][7][8][9][10][11]. Yates and Chapman [5] qualitatively examined the related separation kinematics and characterized the topology as open, because the resulting separation line has a free endpoint on the surface.…”

“…Between 1992 and 1998, Ahn and Simpson [8], Chesnakas and Simpson [9], and Wetzel and Simpson [7] completed wind-tunnel tests on a 6:1 ellipsoid at the Virginia Polytechnic Institute and State University at Reynolds numbers up to 4:2 10 6 and incident angles up to 30 deg. For all studies turbulent boundary-layer transition trips were located 20% of the hull length from the nose.…”

Experimental Validation of the Kinematic Theory of Unsteady Separation

“…For incompressible flow, (3) and (4) show that a knowledge of the time history of wall shear-stress is all that is required to identify the location of fixed unsteady separation. Indeed, one can also consider condition (3) to apply more generally, as the effects of compressibility do not become important until the free stream Mach number reaches approximately 4 (and the formation of shocklets is not seen in boundary layer turbulence until the free stream Mach number of the flow reaches approximately 7) 17 .…”

“…The zero-skin-friction principle 1 has become the most broadly used indicator of separation, even though numerical work in the 1970's by Sears and Tellionis 2,3 and others showed that the principle fails for unsteady flows. Furthermore, it is now widely understood that even in steady threedimensional flows, separation is rarely associated with the vanishing of wall shear-stress 4 . Concluding that vanishing skin friction "does not denote separation in any meaningful sense in unsteady flow", Sears and Tellionis 3 proposed a separation criterion known as the Moore-Rott-Sears (MRS) principle.…”

Instabilities in the Wake of an Inclined Prolate Spheroid

“…Ahn and Simpson (1992), Wetzel & Simpson (1993), Hoang et al (1994a, b), and Fu et al (1994) measured the unsteady flow around spheroids with different aspect ratios and attack angles, mostly focussing on the three-dimensional flow separation. In the late 1990s, Chesnakas & Simpson (1997) further improved their LDV measurement technique and managed to obtain the time-averaged flow field around a 6:1 prolate spheroid. first observed features of cross-flow separation in an inclined spheroid flow, and thereafter accurately measured the separation point on a spheroid under unsteady motion .…”