The United States of America As Represented by the Administrator of the

Bruce J Holmes

Dennis M Bushnell

Thomas C Moore

Harlan K Holmes

Debra L Carraway

Christopher S Domack

Clifford J Obara

Ahmed A Hassan

Glenn L Martin

Paul M Vijgen

Peter D Gall

Floyd G Howard

An improvement in the lift and drag characteristics of a lifting surface is achieved by attaching a serrated panel to the trailing edge of the lifting surface. The serrations may have a saw-tooth configuration, with a 60.degree. included angle between adjacent serrations. The serrations may vary in shape and size over the span-wise length of the lifting surface, and may be positioned at fixed or adjustable deflections relative to the chord of the lifting surface.

Serrated trailing edges for improving lift and drag characteristics of

Disclosed is a method of visualizing laminar to turbulent boundary layer transition, shock location, and laminar separation bubbles around a test surface. A liquid crystal coating is formulated using an unencapsulated liquid crystal operable in a temperature bandwidth compatible with the temperature environment around the test surface. The liquid crystal coating is applied to the test surface, which is preferably pre-treated by painting with a flat black paint to achieve a deep matte coating, after which the surface is subjected to a liquid or gas flow. Color change in the liquid crystal coating is produced in response to differences in relative shear stress within the boundary layer around the test surface.

Method for laminar boundary layer transition visualization in flight

A crossflow vorticity sensor is provided for the detection of crossflow vorticity characteristics. The crossflow vorticity sensor is comprised of crossflow sensors (10) which are non-invasively adhered to swept wing laminar surface (12) either singularly, in multi-element strips (11), in polar patterns (40), or orthogonal patterns (41). These crossflow sensors (10) are comprised of hot-film sensor elements (18) which operate as a constant temperature anemometer circuit to detect heat transfer rate changes. Accordingly, crossflow vorticity characteristics are determined via cross-correlation. In addition, the crossflow sensors (10) have a thickness which does not exceed a maximum value h in order to avoid contamination of downstream crossflow sensors (10).

Crossflow vorticity sensor

This invention is for a passive laminar flow airfoil which has an upper skin 12 and lower skin 14 joined at a trailing edge 16. A leading edge structure 20, such as de-icing equipment, is joined to the upper and lower skins by interface mechanisms 30 and 35. Generally, the interface mechanisms are forward facing steps, with or without adjacent gaps, shaped and dimensioned to accomplish laminar flow using standard airfoil manufacturing techniques.

Geometries for roughness shapes in laminar flow

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Newport News, VA, United States of America

Bruce J Holmes