Possible types of flow on lee-surface of delta wings at supersonic speeds

Abstract

SummaryExperiments were conducted to study the types of flow that occur on the lee surface of delta wings at supersonic speeds. Two sets of flat topped delta wings of different thickness (wedges with 10° and 25° normal angle respectively), each with leading edge sweep angles of 45°, 50°, 60° and 70°, were tested. The measurements, carried out at Mach numbers of 1·4, 1·6, 1·8, 2·0, 2·5 and 3·0, included oil flow visualisations (on both sets of wings) and static pressure distributions (on the thicker wing only). In addition, a 60° sweptback delta wing with a normal angle of 40° was also tested. The tests on this wing included both oil flow visualisations and static pressure measurements. From these and other existing measurements, the leeside flows have been classified into nine distinct types, namely (i) leading edge separated flow with secondary separation, (ii) leading edge separated flow with secondary and tertiary separation, (iii) leading edge separated flow with a shock wave beneath the primary vortex, (iv) leading edge separated flow with shock-induced secondary separation, (v) fully attached flow, (vi) flow attached at the leading edge with inboard shock-induced separation, (vii) mixed type of flow, (viii) flow with a leading edge separation bubble and (ix) leading edge separated flow with a shock wave lying on the lee surface in between the leading edge vortices. These types of flow have been displayed in a plane of Mach number and angle of attack normal to the leading edge. The experimental results indicate that increasing wing thickness has no qualitative effect on the types of flow observed but does shift the boundaries between some of the types of flow.

Measurements of leading-edge vortices on a 75° delta planform wing at M = 2.5

“…In the classical delta wing literature' 27 - 30 Table 2. Both cases have subsonic leading edge so that primary vortices generated by separated flow along the wing leading edge are to be expected.…”

Computational investigation of vortex structure and breakdown over a delta wing at supersonic pitching maneuver

“…Szodruch and Peake [20] proposed a similar classification for delta wings with more thickness than those studied by Miller and Wood. Seshadri and Narayan [21] and Brodetsky et al [22] examined the flow structure in more detail and suggested similar classifications. Vorropoulos and Wendt [23] experimentally found a new flow regime on the leeward side of a delta wing, the flow with the formation of a shock wave under the primary vortex.…”

Aerodynamic Characteristics of a Delta Wing at High Angles of Attack

“…3 Graduate student, Department of Science and Engineering, Ishizaka, Non-member. 4 Professor, Department of Space Transportation Engineering, 3- , and Brodetsky 5 also suggested similar classifications according to α N and M N .…”