HYPERSONIC LAMINAR FLOW CONTROL

摘要

A novel passive control technique for laminar flow over air transportation vehicles and space reentry vehicles flying at high supersonic and hypersonic speeds is disclosed. The control of laminar flow can be achieved by applying an array of surface roughness elements in the region before the laminar-turbulent transition. For example, an array of two-dimensional rings, stripes, or closely packed three-dimensional isolated roughness elements may be used to stabilize the instability waves and delay transition. The roughness elements may have a height between 40% and 60% of the local boundary-layer thickness. The exact location, height, and spacing of surface roughness elements may be determined by a numerical simulation strategy based on the most unstable second mode, e.g. using known eN transition prediction method, experimental measurement, or any other suitable technique.

主权项

1. A supersonic vehicle, comprising:
an exterior surface section having a leading edge for receiving compressible fluid flow over the exterior surface; and one or more surface roughness elements disposed on the exterior surface section to damp disturbances of the flow over the exterior surface; wherein the one or more surface elements are disposed on the exterior surface no closer to the leading edge than a synchronization point of mode S and mode F of the flow over the exterior surface section.