Application of conformal sub boundary layer vortex generators to a foil or aero/ hydrodynamic surface

Abstract

A method of improving aerodynamic performance of foils by the application of conformal, low drag vortex generators. A film of erosion protection material or other conformal material is placed on the foil to provide a medium for the incorporation of planform edge vortex generators. The form edge is shaped to achieve submerged vortex generating shapes of chevron or ogival planforms, extending primarily chordwise on the foil surface. The vortex generators promote improved boundary layer dynamics by mixing free stream flow into the boundary layer while minimising separation and fluid losses. At the trailing edge, the shape formed with the chevrons applied apex forward, acts as a vented gurney tab series and additionally as disruptors to the Von Karman Street wake, delaying sheet rollup into the tip vortice.

Description

RELATED APPLICATIONS[0001]The present application is a continuation-in-part application of U.S. provisional patent application, Ser. No. 61224481, filed Oct. 7, 2009, for ELASTOMERIC VORTEX GENERATORS, by Peter S. Ireland, included by reference herein and for which benefit of the priority date is hereby claimed.[0002]Elastomeric Vortex Generator Provisional patent, Ireland P S, of 10 Jul. 2009. (EFS ID 5676629 Application Number 61224481 Confirmation Number 2708 Title Elastomeric Vortex Generator(s) First Named Inventor Peter Stephen Ireland)FIELD OF THE INVENTION[0003]The present invention relates to the addition of low drag fully submerged conformal vortex generators to a surface in relative motion to a Newtonian fluid and, more particularly, to aeronautical and marine surfaces, blades, rotors, and appendages having a boundary layer with fluid flow across such surface.BACKGROUND OF THE INVENTION[0004]Performance of a foil or surface in a flow of fluid such as air or water is criti...

AI Technical Summary

Benefits of technology

[0038]At a trailing edge of a foil or surface, it is advantageous to apply a series of conformal sub boundary layer vortex generators, with the apex facing forward toward the flow, to develop a set of counter rotating vortices to interact with and disrupt the Von Karman Street sheet into filaments, thereby delaying the onset of tip vortex rollup. Said trailing edge mechanisms additionally advantageously develop a transverse vortex in the wake of the base of the generator, which acts as a lift enhancing tab, advantageously improving lift and drag ratios in specific operational cases. Such an application advantages the lift distribution on a span, by unloading the tip of the span.

[0039]It is further advantageous to provide vortex generation with a mechanism that adds low mass to a system.

[0040]Damage tolerance by material and by design is advantageous for a vortex generating and flow modification system.

Problems solved by technology

It should be noted that in cases where a squat triangular form is produced, and the hypotenuse to adjacent angle is large, in excess of 60 degrees, then the resultant flow may actually be adversely affected such as to increase drag compared to a continuous transverse aft facing step.

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