초록 ▼

A series of parallel riblets extend from a smooth, aerodynamic surface for reducing the skin friction drag of the surface an airstream flows around it. The riblets extend longitudinally along the surface and have a triangular cross-section in the transverse direction. The apex of the cross-section d

A series of parallel riblets extend from a smooth, aerodynamic surface for reducing the skin friction drag of the surface an airstream flows around it. The riblets extend longitudinally along the surface and have a triangular cross-section in the transverse direction. The apex of the cross-section defines a continuous, undulated ridge with peaks and valleys. Measured from the surface, the peaks have a greater height than the valleys. The interaction of the riblets with the structure of the turbulent boundary layer of the airstream reduces the skin friction drag coefficient of the surface by approximately 12% over an identical smooth surface without the riblets. This reduction occurs despite the significant increase in wetted area of the riblet-covered surface over the smooth surface.

대표청구항 ▼

1. An apparatus for reducing skin friction drag on a surface, the apparatus comprising:a plurality of parallel riblets wherein, in a Cartesian coordinate system with x, y, and z-axes, each of the riblets extends lengthwise in an x-direction and has a longitudinal profile in an x-z-plane with a varia

1. An apparatus for reducing skin friction drag on a surface, the apparatus comprising:a plurality of parallel riblets wherein, in a Cartesian coordinate system with x, y, and z-axes, each of the riblets extends lengthwise in an x-direction and has a longitudinal profile in an x-z-plane with a variable height in a z-direction, and wherein the riblets are adapted to be mounted to a surface that is subjected to fluid flow in the substantially x-direction; and wherein each of the riblets has a plurality of peaks in the x-z plane separated by valleys of lesser height in the z-direction.