開水路局所流の機構について

Abstract

The behavior of a local flow near the abrupt contraction of a rectangular channel isinvestigated experimentally and analytically under the condition of a laminar main flow.The flow being three dimensional, the flow visualization method in which small air andhydrogen bubbles are applied is used successfully to measure the flow pattern and thevelocity distribution. Analytically, the vorticity variation along streamlines is made clear.Because, ~ of the difficulty of three-dimensional analysis, however, the two dimensional modelof the flow is constructed to analize approximately the flow patterns under the assumptionthat the mass transport from one section parallel to the channel bed to another is reducedto the source or sink line along the contraction wall. The result obtained analyticallyshows a good agreement with the experimental flow patterns.