AN EXPERIMENTAL-STUDY OF FLOW OVER ARTIFICIAL BED FORMS

The boundary characteristics of flow over bed forms determine their be haviour and interaction with associated turbulent flow and sediment tr ansport. The effects of bed-form geometry, surface roughness and disch arge on boundary shear stress, pressure, water surface profile and sep aration length have been investigated experimentally at shallow (relat ive to bed-form height) flow depths. The length of separation zone was found to depend on the Froude number, gram roughness and bed-form geo metry, and to be significantly greater than as measured previously at greater relative flow depths. Boundary shear stress is influenced stro ngly by discharge and bed-form geometry, and weakly by surface roughne ss.