METHODS FOR MEASURING THE FREE SURFACE POSITION IN LABORATORY FLOWS

摘要

Two methods are presented for measuring the free surface position in the flow around a laboratory scale model Crump weir. The first was applied to the measurement of upstream stage, and used a differential pressure transducer in combination with static pressure tappings and a reservoir that retained a water level at weir crest level. The second was applied to the rapidly varied flow over the crest and used a miniature wave probe and monitor. For some applications, both methods improve upon the pointer gauge and vernier scale combination. However, the wave probe accuracy depends upon the flow regime and depth of immersion.