Abstract: A flexible composite sheet (FCS) comprising a membrane, a substrate coupled to the membrane, and a plurality of ridges coupled between the membrane and the substrate, wherein a vibratory motion is induced from the flow to at least one segment of a membrane spanning a distance s, wherein the vibratory motion is reflected from at least one segment of the membrane to the flow, and wherein a reduction in fluctuations is caused in the flow pressure gradient and freestream velocity U at all frequencies except around f, where f?U/s. When coupled to a heat exchanger fin, the FCS can enhance heat transfer without enhancing flow pressure drop. The FCS has other flow control applications, such as a drag reduction when coupled to an aircraft wing.

Abstract: A flexible composite sheet (FCS) comprising a membrane, a substrate coupled to the membrane, and a plurality of ridges coupled between the membrane and the substrate, wherein a vibratory motion is induced from the flow to at least one segment of membrane spanning a distances, wherein a favorable pressure gradient aids the flow and an adverse pressure gradient opposes the flow; wherein the vibratory motion is reflected from at least one segment of the membrane to the flow, and wherein a reduction in fluctuations is caused in the flow pressure gradient and freestream velocity U except where the frequency is approximately equal to =U/s. The FCS has other flow control applications, such as a drag reduction when coupled to an aircraft wing.

Abstract: A flexible composite sheet is disclosed. The flexible composite sheet (FCS) comprising a membrane, a substrate coupled to the membrane, and a plurality of ridges coupled between the membrane and the substrate, wherein a vibratory motion is induced from the flow to at least one segment of a membrane spanning a distance s, wherein the vibratory motion is reflected from at least one segment of the membrane to the flow, and wherein a reduction in fluctuations is caused in the flow pressure gradient and freestream velocity U at all frequencies except around f, where f≈U/s. When coupled to a heat exchanger fin, the FCS can enhance heat transfer without enhancing flow pressure drop. The FCS has other flow control applications, such as drag reduction when coupled to an aircraft wing.