Patent ID: 8113469

Claim:
An aerodynamic or hydrodynamic wall surface configured to modify the interaction of a boundary layer of a fluid with the wall surface, comprising: at least one array of roughness elements disposed on and extending therefrom the surface, wherein each roughness element has a front, upstream surface and an opposing rear, downstream surface, wherein each roughness element has a peripheral edge that has an upper portion that tapers to a top and a bottom portion that tapers to a base, which is connected to the wall surface, wherein each roughness element is positioned adjacent and aligned substantially transverse to the flow of fluid across the surface such that a distance between a medial portion of the peripheral edges of adjacent and aligned roughness elements is less than the distance between the respective tops of the roughness elements and is less than the distance between the respective bases of the roughness elements, wherein a distance from the front surface to the rear surface in the medial portion of each roughness element is greater than the distance from the front surface to the rear surface in the upper portion and the bottom portion of each roughness element, wherein a peak longitudinal height of each roughness element is greater than a peak width of each roughness element, wherein the width of the medial portion of each roughness element is greater than the width of the upper portion and the bottom portion of each roughness element, wherein the array of roughness elements defines a plurality of cavities, and wherein the thickness of the boundary layer is in a range of 10% to 30% of a cavity height of each cavity such that shear layer instabilities of cavity vortexes that form therein the plurality of cavities are reduced.