Abstract: A corner vortex forms at the corners of a square or rectangular wind tunnel or water tunnel and disrupts the flow and creates excessive drag, turbulence, noise and wake. The corners defined by a wing/fuselage interface creates the same type of situation. The suppressor provides many small corners to prevent forming of the single large vortex. A honeycomb or mesh provides parallel passageways, each having a size that is a fraction (1/5th to 1/10th) of the depth of the boundary layer (defined as that point in the fluid flow where the velocity is 99% of free stream velocity.

Abstract: A housing block is provided having an upper surface conforming to the test surface of a model or aircraft. An oil film is supplied upstream of a transparent wedge window located in this upper surface by an oil pump system located external to the housing block. A light source located within the housing block supplies a light beam which passes through this transparent window and is reflected back through the transparent window by the upper surface of the oil film to a photo-sensitive position sensor located within the housing. This position sensor allows the slope history of the oil film caused by an aerodynamic flow to be determined. The skin friction is determined from this slope history. Internally located mirrors augment and sensitize the reflected beam as necessary before reaching the position sensor. In addition, a filter may be provided before this sensor to filter the beam.