Some remarks on a synthetic turbulent boundary layer

An experiment consisting of the generation of a regular array of turbulent spots and their transmission down a synthetic boundary layer was designed in an effort to devise a method for localizing large scale coherent structures in turbulent shear flow. The experiment used a laser Doppler velocimeter for the measurements and an 8 ft long plate model with an elliptical nose. Small disturbances were generated from a row of holes by intermittently pumping out jets of water. It is suggested that a turbulent spot is a large U-shaped vortex which moves down the plate with its ends slipping along the surface.