年間 4 号発行
ISSN 印刷: 1065-3090
ISSN オンライン: 1940-4336
Indexed in
REDUCTION OF SCOUR AROUND BRIDGE PIERS USING A VORTEX GENERATOR
要約
Local scours around bridge piers is a complex phenomenon that imperils the safety of river bridges. The flow pattern and scouring mechanism are very complicated. Reduction of scours around obstacles has taken too much research but few countermeasures have been proposed. In this paper, we propose a new countermeasure; it consists of vortex generator (VG) geometry attached to the bridge pier. This geometry is used to break the downflow and reduces the wake zone behind the bridge pier. For that purpose, a number of numerical simulations have been carried out using a finite volume method (FVM) and for the turbulence model we have chosen the detached eddy simulation (DES) for its capability to capture the rich dynamics of the horseshoe vortex at the upstream junction between the pier and the bed. The results of the present study show that the vortex generator attached to the pier strongly affects the flow pattern around it; also, the results show a reduction of about 21% in the bed shear stress.
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Ali, K.H.M and Karim, O., Simulations of Flow around Piers, J. Hydraulic Res., vol. 42, no. 2, pp. 161-174, 2002.
-
Briaud, J.L., Ting, F., Chen, H., Cao, Y., Gudavalli, R., and Perugu, S., SRICOS: Prediction of Scour Rate in Cohesive Soils at Bridge Piers, J. Geo. Geoenv. Soc. Am., ASCE, vol. 125, no. 4, pp. 237-246, April 1999.
-
Dargahi, B., The Turbulent Flow Field around a Circular Cylinder, J. Exp. Fluids, vol. 8, nos. 1-2, pp. 1-12, 1989.
-
Debnath, K. and Chaudhuri, S., Local Scour around Non-Circular Piers in Clay-Sand Mixed Cohesive Sediment Beds, J. Eng. Geology, vol. 151, Technical Note, Elsevier, pp. 1-14, 2012.
-
Dey, S., Bose, S.K., and Sastry, G.L.N., Clear Water Scour at Circular Piers: A Model, J. Hydraul. Eng., vol. 121, no. 12, pp. 869-876, 1995.
-
Escauriaza, C. and Sotiropoulos, F., Reynolds Number Effects on the Coherent Dynamics of the Turbulent Horseshoe Vortex System, J. Flow Turbulence Combust., vol. 86, no. 2, pp. 231-262, 2011.
-
Graf, W.H. and Istiarto, I., Flow Pattern in the Scour Hole around a Cylinder, J. Hydraulic Res., vol. 40, no. 1, pp. 13-20, 2002.
-
Guemou, B., Seddini, A., and Ghenim, A.N., Numerical Investigations of the Bridge Pier Shape Influence on the Bed Shear Stress, EJGE, vol. 18, Bund. Y, pp. 5685-5698, 2013.
-
Guemou, B., Seddini, A., and Ghenim, A.N., Numerical Investigations of the Round-Nosed Bridge Pier Length Effects on the Bed Shear Stress, Prog. Comput. FluidDyn., vol. 16, no. 5, pp. 313-321, 2016.
-
Huang, W., Yang, Q., and Xiao, H., CFD Modeling of Scale Effects on Turbulence Flow and Scour around Bridge Piers, J. Computers Fluids, vol. 38, pp. 1050-1058, 2009.
-
Khosronejad, A., Kang, S., and Sotiropoulos, F., Experimental and Computational Investigation of Local Scour around Bridge Piers, J. Adv. Water Resources, vol. 37, pp. 73-85, 2012.
-
Liu, C., Liu, C., and Wenxing, M., RANS, Detached Eddy Simulation and Large Eddy Simulation of Internal Torque Converters Flows: A Comparative Study, J. Eng. Appl. Comput. Fluid Mech., vol. 9, no. 1, pp. 114-125, 2015.
-
Masjedi, A., Bejestan, M.S., and Esfandi, A., Reduction of Local Scour at a Bridge Pier Fitted with a Collar in a 180 Degree Flume Bend, 9th Int. Conf. on Hydrodynamics, October 11-15, Shanghai, China, vol. 22, no. 5, pp. 669-673, 2010.
-
Najafzadeh, M. and Barani, Gh.A., Comparison of Group Method of Data Handling Based Genetic Programing and Back Propagation Systems to Predict Scour Depth around Bridge Piers, J. Sciebtia Iranica, vol. 18, no. 6, pp. 1207-1213, 2011.
-
Oliveto, G. and Hager, W.H., Temporal Evolution of Clear-Water Pier and Abutment Scour, J. Hydraul. Eng., vol. 128, no. 9, pp. 811-820, 2002.
-
Paik, J., Escauriaza, C., and Sotiropoulos, F., On the Bimodal Dynamics of the Turbulent Horseshoe Vortex System in a Wing-Body Junction, J. Phys. Fluids, vol. 19, no. 4, pp. 1-20, 2007.
-
Pal, M.N., Singh, K., and Tiwari, N.K., M5 Model Tree for Pier Scour Prediction Using Field Dataset, J. Civil Eng., vol. 16, no. 6, pp. 1079-1084, 2011.
-
Pasiok, R. and Stilger-Szydlo, E., Sediment Particles and Turbulent Flow Simulation around Bridge Piers, Arch. Civil Mech. Eng., vol. 10, no. 2, pp. 67-79, 2010.
-
Richardson, E.V. and Davis, S.R., Evaluating Scour at Bridges, 4th Ed., Federal Highway Administration, Washington, DC, Hydraulic Engineering Circular No. 18, FHWA NHI 01-001, 2001.
-
Roulund, A., Utlu Sumer, B., Fredsoe, J., and Michelsen, J., Numerical and Experimental Investigation of Flow and Scour around a Circular Pile, J. FluidMech., vol. 534, pp. 351-401, 2005.
-
Spalart, P.R., Jou, W.-H., Strelets, M., and Allmaras, S.R., Comments on the Feasibility of LES for Wings, and on a Hybrid RANS/LES Approach, Proc. of the First AFOSR Int. Conf. on DNS/LES, Ruston, LA, 1997.
-
Sumer, B.M., Mathematical Modeling of Scour: A Review, J. Hydraulic Res., vol. 45, no. 6, pp. 723-735, 2007.
-
Unger, J. and Hager, W.H., Down-Flow and Horseshoe Vortex Characteristics of Sediment Embedded Bridge Piers, J. Exp. Fluids, vol. 42, no. 1, pp. 1-19, 2007.
-
Wardhana, K. and Hadipriono, F., Analysis of Recent Bridge Failures in the United States, J. Perform. Constr. Facil, ASCE, vol. 17, no. 3, pp. 144-150, 2003.
-
Zhao, M., Cheng, L., and Zang, Z., Experimental and Numerical Investigation of Local Scour around a Submerged Vertical Circular Cylinder in Steady Currents, J. Coast. Eng., vol. 57, no. 8, pp. 709-721, 2010.