ADAPTATION OF THE RADIAL FLOW ENERGY DISSIPATOR FOR USE WITH CIRCULAR OR BOX CULVERTS

METHODS OF ADAPTING A RADIAL-FLOW ENERGY DISSIPATOR, PREVIOUSLY DEVELOPED FOR A BOX CULVERT, TO A CIRCULAR ONE WERE EXAMINED. THE BASIC CRITERIA USED IN INVESTIGATING THE EFFECTIVENESS OF VARIOUS GEOMETRIC ARRANGEMENTS AS ENERGY DISSIPATOR WERE THE STABILITY OF HYDRAULIC JUMP, THE EFFICIENCY OF THE SPREADING ACTION, AND THE DEGREE OF VELOCITY REDUCTION IN THE JUMP. THE BASIC CONCEPT FOR THE NEW ENERGY DISSIPATOR WAS TO DEVISE A MEANS BY WHICH THE FLOW AT THE CULVERT OUTLET COULD BE SPREAD IN WIDTH TO SEVERAL TIMES THE WIDTH OF THE CULVERT. THIS WAS ACCOMPLISHED BY INCORPORATING A DOWNWARD-CURVED ENTRANCE CHANNEL NEAR THE CULVERT OUTLET, FOLLOWED BY A SHARP UPWARD CURVE AT THE BEGINNING OF A HORIZONTAL BASIN. THE UPWARD VERTICAL CURVE PRODUCED A PRESSURE FIELD CAUSING THE SUPERCRITICAL FLOW TO SPREAD IN A RADIAL DIRECTION BETWEEN FLARED WINGWALLS, AND WITH PROPER TAILWATER CONDITIONS A CIRCULAR HYDRAULIC JUMP WAS FORMED ON THE HORIZONTAL APRON. WATER FROM A HEAD TANK WAS LED INTO A SIX-INCH CULVERT THREE FEET LONG. PROVISION WAS MADE FOR INSTALLING EITHER A CIRCULAR CULVERT OR A SQUARE BOX CULVERT AND FOR CONTROLLING AND MEASURING THE DISCHARGE AS WELL AS INDEPENDENTLY SETTING THE DEPTH OF FLOW. IN THIS WAY, IT WAS POSSIBLE TO REPRODUCE A DESIRED RATE OF DISCHARGE AND FROUDE NUMBER AT THE CULVERT OUTLET. A NUMBER OF DIFFERENT FORMS OF THE ENTRANCE CHANNEL LEADING FROM THE CULVERT OUTLET DOWN AN INCLINE TO THE HORIZONTAL FLOOR OF THE STILLING BASIN WERE TRIED. THE OVERALL COMPARISON OF THE PERFORMANCE CHARACTERISTICS OF SEVEN DIFFERENT STRUCTURAL CONFIGURATIONS INDICATED A SMALL DIFFERENCE IN THE PERFORMANCE OF VARIOUS ARRANGEMENTS. THESE STRUCTURES INCLUDED VARIATIONS IN THE DISTANCE ALONG THE CENTERLINE FROM THE END OF THE CIRCULAR CULVERT TO THE BEGINNING OF THE CURVED BOTTOM DROP SECTION, VARIATIONS IN THE SHAPE OF THE CURVED BOTTOM CHANNEL, AND ELIMINATION OF THE CURVED DROP SECTION, BY REPLACING IT WITH A SIMPLE VERTICAL WALL. THE MORE COMPLEX GEOMETRIC FORMS SHOWED NO PARTICULAR IMPROVEMENT OVER THE SIMPLE CURVED DROP SECTION. FROM THE EVALUATED RESULTS IT APPEARED THAT THE RELATIVE SIMPL-CITY OF CONSTRUCTION WAS A STRONG ARGUMENT IN FAVOR OF THE ARRANGEMENTS WITH THE SIMPLE CURVED DROP AND STRAIGHT HORIZONTAL TRANSVERSE ELEMENTS.

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: 88p

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Filing Info

  • Accession Number: 00204324
  • Record Type: Publication
  • Report/Paper Numbers: 116-1, Research Project 3-5-69-116
  • Files: TRIS, ATRI
  • Created Date: May 10 1971 12:00AM