EFFECT OF EXTERNALLY IMPOSED ROTATION ON DISCHARGE CHARACTERISTICS OF BROAD-CRESTED WEIRS

Abstract

This disflertation is an exploratory study of the offcct of o n eternally aposed rotation on tho discharge characteristics of broad-created tr ira. The study was taken up iith the intention of verifying tho premie that supply of additional momentum near the crest of a trefr should result in a hiCher discharge coefficient,. thus enabling design of weirs with a lower affiux • A semi-theoretical study has been made for free overfall suppressed weirs having vertical faces with a rotating cylinder at top 4 corner. A theorotical relation was first obtained for discharge over broad-created weir with rotating cylinder by assuming suitable velocity distribution- 1-aw for the-imposed rotational flow. However, this equation showed syotemetic departure from experimental observations. As such an approach based on dimensional analysis was adopted to obtain a discharge relationship for such weirs. The roaulto show that thoro is substantial increase In discharge--by as much as 30 nor cent due to rotation at high speeds and low heads.