S470 : Laboratory study of three-dimensional flow pattern around the bridge abutment with different shapes
Thesis > Central Library of Shahrood University > Agricultural Engineering > MSc > 2019
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Abstarct: One of the influential factors in the occurrence of the maximum scour depth around the bridge abutments is the shape of the abutment. Although researchers have admitted the effect of the shape of the abutment on the scour depth around the abutment, but little research has been done on the flow pattern around the various shapes of the abutment. Theoretically, 3D separation flow and its interaction with the sediment transport create a lot of problems in the analysis of local scour around the abutment. Precise measurements of flow around the bridge abutment can help to analyze the flow. In this research, the flow pattern around the five abutments with different shapes i.e. triangular, square, trapezoidal, semicircular, and trapezoidal was examined. The experiments were done with three discharges of 24, 26 and 28 lit/s. In all experiments, the flow depth was fixed at 10 cm and sediment with mean diameter of 0.85 mm was used. The bed topography was taken with a point gauge and 3D velocity measurements were performed using an ADV. Using velocity data collected by 3D velocity components, velocity vectors, turbulent profiles and Reynolds shear stress profiles were investigated. Quadrant analysis was also used to determine the contribution of each occurrence to scouring. The results showed that the maximum and minimum scour depth was related to the triangular and trapezoidal shape, respectively. Using the abutment with triangular shape reduced the maximum scour depth 39.33% compared to the trapezoidal shape for discharge of 28 lit/s. Also, study of three dimensional velocity components, turbulence profiles and Reynolds shear stresses showed that although in all the abutments the only cause for the maximum scour depth is the horsehole vortices, but in the trapezoidal abutment the combination of vortex vortices and secondary vortices caused the maximum scour depth.
Keywords:
#Flow pattern #scour #bridge abutment #three-dimensional velocity Link
Keeping place: Central Library of Shahrood University
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Keeping place: Central Library of Shahrood University
Visitor: