Experimental Investigation of Bed Topography of A 90 Degree Mild Bend With Triangular Vane Attached to The Bank

Abstract

In the present paper the Triangular Shape Vane (TSV) attached to the bank of a flume bend for the purpose of introducing a new measure for reducing bank erosion has been experimentally investigated. Tests carried out at 90-degree mild flume with ratio of radius to width equal to 4. For main tests, nine triangular vanes with fixed distance of 70cm equal to 5 times the effective vane length at angle of 20 degree to the upstream was attached to the outer bank and tested under four different flow conditions of which Froude number was equal to o.24, 0.26, 0.29 and 0.32. Tests also were carried out using regular Rectangular Shape Vanes(RSV) for Froude number equal to 0.26. At the end of each test, bed topography was measured. Plots of bed topography and longitude bed profile show that the scour hole at the noise of both vanes are developed with its maximum depth increases as the flow conditions is increased. Comparison of the scour depth for both TSV and RSV proved that the scour depth for TSV are 80% less than the scour depth of RSV.

Keywords

• vane attached to the bank
• 90° bend
• froude number
• scour depth