TAPERED BOX CULVERT INLETS WITH FALL CONCENTRATION IN THE INLET STRUCTURE

THE HYDRAULIC CAPACITIES OF TAPERED INLETS TO BOX CULVERT BARRELS, WITHIN WHICH A SUBSTANTIAL FALL OF THE INVERT GRADE IS PROVIDED BY SLOPING THE INLET, WERE INVESTIGATED FOR A RANGE OF POSSIBLE INLET FORMS. SCALE MODELS WERE USED TO DETERMINE DISCHARGE CAPACITY OF THESE INLETS OPERATING WITH CONTROL AT THE FACE SECTION, AT THE THROAT SECTION AND AT INTERMEDIATE CONTROL SECTIONS. THE RESULTS ARE EXPRESSED IN THE FORM OF ENERGY EQUATIONS RELATING THE RATE OF FLOW TO DIMENSIONS AND FORM OF THE CONTROL SECTION BY USE OF DISCHARGE COEFFICIENTS. THE REPORT SHOWS THAT TAPERED AND SLOPED INLETS CAN PROVIDE SUBSTANTIAL INCREASES OF DISCHARGE CAPACITY OVER THAT OF A CONVENTIONAL BOX CULVERT OF EQUAL BARREL SIZE AT AN EQUAL DEPTH OF HEADWATER, THE DEGREE OF INCREASE DEPENDING UPON THE FALL FROM INLET CREST TO THROAT AND THE RELATIVE DEPTH OF HEADWATER. /AUTHOR/