Hydraulic structure fairing with vortex generator

Abstract

Discussed are several practical cost-effective refinements, extensions, additions, and improvements to the manufactured three-dimensional convex-concave fairing with attached vortex generators that was disclosed by Simpson et al. (U.S. Pat. No. 8,348,553). Extensions are disclosed for bridge piers and abutments at larger angles of attack of up to 45°, for piers and abutments downstream of a bend in a river where there is large-scale swirling approach flow, and for piers in close proximity to an adjacent pier of abutment.

1 . A convex-concave fairing for a hydraulic structure comprising:
 a piece-wise continuous streamlined fairing surface installed around a perimeter of the hydraulic structure and extending from near the height above a river on the hydraulic structure to a bed of said river surrounding the hydraulic structure, said piece-wise continuous fairing completely enveloping the hydraulic structure and providing a piece-wise continuous faired shape in a direction of flow of the river, wherein the piece-wise continuous streamlined fairing surface comprises a plurality of continuous surfaces that are assembled together to form the piece-wise continuous streamlined fairing surface, and wherein the discontinuity in the piece-wise continuous streamlined fairing surface occurs at the intersection of the plurality of the continuous surfaces;   at least one vortex generator attached to the piece-wise continuous fairing surface along a longitudinal distance of a stern to stern dimension of said piece-wise continuous fairing surface, and being proximal to the bed of the river in a flow region void of adverse pressure gradients that would persist downstream of said vortex generator for at least one length of said generator, so as to energize a portion of near wall flow with higher-momentum outer layer flow to produce a steady, compact separation and wake and prevent formation of scouring vortices within river flow.   
     
     
         2 . A fairing as in  claim 1 , wherein; said hydraulic structure is a bridge abutment. 
     
     
         3 . A fairing as in  claim 1 , wherein: said hydraulic structure is a pier and said vortex generators are positioned on opposed surfaces thereof. 
     
     
         4 . A fairing as in  claim 1 , wherein: said vortex generators are tetrahedral in shape and include four triangular faces, three of which meet at each vertex, and are constructed of cast-in-place, pre-cast, or sprayed concrete, metal, composite, fiber reinforced polymers, or combinations thereof. 
     
     
         5 . A piece-wise continuous fairing in  claim 1 , wherein: the fairing is constructed of cast-in-place, pre-cast, or sprayed concrete, metal, composite, fiber reinforced polymers, or combinations thereof, that is fit or cast over one or more existing or new hydraulic structures around the base of these structures and above and around their footings. 
     
     
         6 - 7 . (canceled) 
     
     
         8 . A fairing as in  claim 5 , wherein: the fairing surface is comprised of elements that are premanufactured and interlock using matching keys or alignment surfaces among individual premanufactured elements. 
     
     
         9 . A method for making a convex-concave fairing for a hydraulic structure whose nose and tail sections and dogleg shape prevents the formation of scouring vortices for large river inflow angle of attack of flow passing said hydraulic structure, the method comprising the steps of:
 selecting, in accord with computational fluid dynamics and water flume river bed scour studies, a suitable piece-wise continuous streamlined fairing whose nose and tail sections are aligned with the on-coming flow direction, and installing said fairing around a perimeter of said hydraulic structure and extending from a height above said river on said structure to a bed of said river surrounding said structure, said piece-wise continuous fairing completely enveloping said perimeter of said structure and providing a piece-wise continuous faired shape to said hydraulic structure in a direction of flow of said river, wherein the piece-wise continuous streamlined fairing comprises a plurality of continuous surfaces that are assembled together to form the piece-wise continuous streamlined fairing surface, and wherein the discontinuity in the piece-wise continuous streamlined fairing surface occurs at the intersection of the plurality of the continuous surfaces;   attaching vortex generators to surfaces of said piece-wise continuous fairing downstream from a forward upstream portion of the piece-wise continuous streamlined fairing and along a longitudinal distance of a stem to stern dimension of said piece-wise continuous fairing, and being proximal to said river bed in a flow region void of adverse pressure gradients that would persist downstream of said vortex generator for at least one length of said generator, so as to energize a near wall portion of the flow of river current with higher momentum outer layer flow to induce steady, compact separation and wake and thereby oppose formation of scouring vortices within said river flow around said fairing.   
     
     
         10 . A method as in  claim 9 , wherein:
 said vortex generators are tetrahedral in shape and include four triangular faces, three of which meet at each vertex.   
     
     
         11 - 15 . (canceled) 
     
     
         16 . A fairing as in  claim 1 , further comprising a ramp upstream of and attached to the piece-wise continuous streamlined fairing surface. 
     
     
         17 . A fairing as in  claim 16 , further comprising a vortex generator in front of each leading edge corner of the ramp.