BOUNDARY-LAYER MEASUREMENTS ON SEVERAL POROUS MATERIALS WITH SUCTION APPLIED

摘要

The boundary layer measured on the smooth impervious plate was laminar at the upstream end of the suction area, but was of the transitional type after having traversed the 3-l/2 inches to the downstream measuring station. Without suction none of the velocity profiles measured on the porous materials were laminar at the downstream station. The thickness of the boundary layer was increased and its form altered from that measured on the impervious plate by amounts which depended on the nature of the surface of the material. With suction applied the form of the boundary layers was greatly altered, and both the displacement thickness and the momentum thickness were reduced. The rate of thinning diminished with increasing suction, and the boundary-layer displacement and momentum thicknesses on all of the porous materials appeared to be approaching a low ultimate value with increasing suction velocity.