The sharp edge of Damocles

Acoustic streaming of a sharp edge.

Anomalous acoustic streaming is observed emanating from sharp edges of solid bodies that are vibrating in fluids. The streaming velocities can be orders of magnitude higher than expected from the Rayleigh streaming at similar amplitudes of vibration. Acoustic velocity of fluid relative to a solid body diverges at a sharp edge, giving rise to a localized time-independent body force acting on the...

Simulation of Sharp Leading Edge Aerothermodynamics

Future hypersonic vehicles are likely to use sharp leading edges on wings and engine inlets to reduce drag. The radius of curvature associated with such structures may be one centimeter or less. The very small size leads to high heating rates that can be accommodated using advanced materials. An additional aspect of the small size concerns the basic gas dynamics. At such small scales, the conti...

Patents of Damocles

Mean Velocity and Static Pressure in a Sharp-edge Circular Nozzle Jet

An axisymmetric jet issued from a sharp edged circular convergent nozzle has been studied experimentally in the near field at Reynolds number 5.3x104  to search the saddle shape behavior of mean velocity and the role of mean static pressure in the jet flow. Due to the vena contracta effect the centerline mean velocity of the jet increases about 4.2% of its exit value and corresponding decrease ...

The edge tenacity of a split graph

The edge tenacity Te(G) of a graph G is dened as:Te(G) = min {[|X|+τ(G-X)]/[ω(G-X)-1]|X ⊆ E(G) and ω(G-X) > 1} where the minimum is taken over every edge-cutset X that separates G into ω(G - X) components, and by τ(G - X) we denote the order of a largest component of G. The objective of this paper is to determine this quantity for split graphs. Let G = (Z; I; E) be a noncomplete connected split...