Analysis of flow over horizontal transverse bottom racks

ABSTRACT A rack set in the bottom of a channel is often used as a hydraulic structure for intake or an outlet for flow. The flow through the bottom racks is a typical case of spatially varied flow with decreasing discharge. In the present work, experiments have been conducted to study flow diversion from transverse bar bottom rack under varying flow conditions i.e. Froude number ranging from 0.1 to 1.5 and ratio of transverse bar spacing to rack length ranging from 0.041 to 0.102. To study discharge characteristics, invariant specific energy assumption is utilized. The variation of Mostkow's discharge coefficient, which is based on invariance of specific energy along the bottom rack, is investigated with Froude number as well as bottom rack parameters. Existing functional forms of discharge coefficient variation in case of longitudinal bar bottom racks have been utilized to develop relationships for discharge coefficient variation in case of transverse bar bottom racks. Observed and computed values of dis...