Hydrodynamics of Flow Obstructed by Inline and Eccentrically-Arranged Circular Piers on a Horizontal Bed Surface
Tóm tắt
An attempt has been made to study and analyse the hydrodynamic effects of turbulent flow including its pattern and characteristics around three identical circular shaped piers. Experimentation was conducted under clear-water scour condition. Three pier groups were placed with inline and eccentric arrangement in tandem manner on a flume. Two piers were positioned inline along the flow direction and third pier was placed eccentrically in the middle of two inline piers having a transverse distance equal to three times of pier width. Three dimensional velocities were gauged at a horizontal plane located at 4% depth above the zero bed level. The readings were captured in the Cartesian coordinate-system to compute the time-mean longitudinal, transversal and vertical velocities. The hydrodynamic consequences of three piers arrangement near the horizontal bed were investigated. The contour profile and variations of time aggregated mean velocity components, kinetic energy and turbulence intensities are measured or determined and analysed. Velocity vectors and absolute velocity at horizontal plane obtained from velocity measuring areas are utilised to explain further hydrodynamic flow features. The measured depth for scour at equilibrium state for the eccentric middle pier is observed higher than the inline front and inline rear circular piers. The three pier group positioning and the interfering between the circular piers act an important function in flow characteristics and for creating and forming the larger scoured depth around the eccentric middle pier.
Tài liệu tham khảo
H.N.C. Breusers, G. Nicollet, H.W. Shen, Local scour around cylindrical piers. J. Hydraul. Res. 15(3), 211–252 (1977)
A.J. Raudkivi, R. Ettema, Clear water scour at cylindrical piers. J. Hydraul. Eng. 109(3), 338–350 (1983)
S. Das, R. Das, A. Mazumdar, Variations of clear water scour geometry at piers of different effective widths. Turk. J. Eng. Environ. Sci. 38(1), 97–111 (2014)
S. Das, R. Ghosh, R. Das, A. Mazumdar, Clear water scour geometry around circular piers. Ecol. Environ. Conserv. 20(2), 479–492 (2014)
S. Dey, Local scour at piers, part 1: A Review of development of research. Int. J. Sediment Res. 12(2), 23–44 (1997)
P. Khwairakpam, S.S. Ray, S. Das, R. Das, A. Mazumdar, Scour hole characteristics around a vertical pier under clear water scour conditions. ARPN J. Eng. Appl. Sci. 7(6), 649–654 (2012)
S. Das, R. Das, A. Mazumdar, Scour mechanism around piers at clear water equilibrium condition. Int. J. Adv. Eng. Res. Dev. 1(10), 88–94 (2014)
S. Das, R. Das, A. Mazumdar, Vorticity and circulation of horseshoe vortex in equilibrium scour holes at different piers. J. Inst. Eng. India Ser. A 95(2), 109–115 (2014)
S. Dey, S.K. Bose, G.L.N. Sastry, Clear water scour at circular piers: A model. J. Hydraul. Eng. 121(12), 869–876 (1995)
S. Dey, R.V. Raikar, Characteristics of horseshoe vortex in developing scour holes at piers. J. Hydraul. Eng. 133(4), 399–413 (2007)
S. Das, S. Ghosh, A. Mazumdar, Flow field past a triangular pier due to sediment transportation at clear water equilibrium scour hole. Int. J. Emerg. Trends Eng. Dev. 7(2), 380–388 (2012)
B.W. Melville, A.J. Raudkivi, Flow characteristics in local scour at bridge piers. J. Hydraul. Res. 15(4), 373–380 (1977)
S. Das, R. Das, A. Mazumdar, Vortex flow field past a cylinder under clear water scour regime, in Proceeding of International Conference on Applications of Fluid Engineering (CAFE-2012), Greater Noida, UP, India, (2012)
S. Das, R. Das, A. Mazumdar, Circulation characteristics of horseshoe vortex in the scour region around circular piers. Water Sci. Eng. 6(1), 59–77 (2013)
R. Ettema, G. Kirkil, M. Muste, Similitude of large scale turbulence in experiments on local scour at cylinders. J. Hydraul. Eng. 132(1), 33–40 (2006)
S. Das, R. Midya, R. Das, A. Mazumdar, A study of wake vortex in the scour region around a circular pier. Int. J. Fluid Mech. Res. 40(1), 42–59 (2013)
S. Das, R. Das, A. Mazumdar, Comparison of characteristics of horseshoe vortex at circular and square piers. Res. J. Appl. Sci. Eng. Technol. 5(17), 4373–4387 (2013)
A. Roulund, B.M. Sumer, J. Fredsoe, J. Michelsen, Numerical and experimental investigation of flow and scour around a circular pile. J. Fluid Mech. 534, 351–401 (2005)
S. Das, A. Mazumdar, Comparison of kinematics of horseshoe vortex at a flat plate and different shaped piers. Int. J. Fluid Mech. Res. 42(5), 418–448 (2015)
S. Das, S. Thakurta, R. Das, A. Mazumdar, Turbulent flow field in clear water equilibrium scour hole at triangular pier. in International Symposium of Sustainable Infrastructure Development, Bhubaneswar: India, (2013), pp. 401–411
H. Akilli, A. Akar, C. Karakus, Flow characteristics of circular cylinders arranged side-by-side in shallow water. Flow Meas. Instrum. 15(4), 187–189 (2004)
D. Sumner, S.S.T. Wong, S.J. Price, M.P. Paidoussis, Fluid behavior of side-by-side circular cylinders in steady cross-flow. J. Fluids Struct. 13(3), 309–338 (1999)
A.B. Ashtiani, A.A. Kordkandi, Flow field around single and tandem piers. Flow Turbul. Combust. 90(3), 471–490 (2013)
S. Das, S. Ghosh, A. Mazumdar, Kinematics of horseshoe vortex in a scour hole around two eccentric triangular piers. Int. J. Fluid Mech. Res. 41(4), 296–317 (2014)
S. Das, A. Mazumdar, Turbulence flow field around two eccentric circular piers in scour hole. Int. J. River Basin Manag. 13(3), 343–361 (2015)
N. Solaimani, A. Amini, H. Banejad, P.T. Ghazvinei, The effect of pile spacing and arrangement on bed formation and scour hole dimensions in pile groups. Int. J. River Basin Manag. 15(2), 219–225 (2017)
S. Das, R. Das, A. Mazumdar, Comparison of local scour characteristics around two eccentric piers of different shapes. Arab. J. Sci. Eng. 41(4), 1193–1213 (2016)
A.V. Voskoboinick, V.A. Voskoboinick, A.A. Voskoboinick, Junction flow of three-row pile grillage on a flat plate. Part 1. Horseshoe vortex generation. Appl. Hydromech. 10(3), 28–39 (2008)
M.M. Zdravkovich, The effects of interference between circular cylinders in cross flow. J. Fluid. Struct. 1(2), 239–261 (1987)
S.A. Michael, G.M. Mohamed, S.B.A.M. Mohamed, Wake vortex scour at bridge piers. J. Hydraul. Eng. 117(7), 891–904 (1991)
S. Das, R. Das, A. Kuila, A. Mazumdar, Analysis of clear-water equilibrium scour around two eccentric circular piers to increase self dredging, in Seminar on Dredging: Equipment and Applications, (EADA), Kolkata, India, (2014)
K.R. Elliott, C.J. Baker, Effect of pier spacing on scour around bridge piers. J. Hydraul. Eng. 111(7), 1105–1109 (1985)
R. Das, P. Khwairakpam, S. Das, A. Mazumdar, Clear-water local scour around eccentric multiple piers to shift the line of sediment deposition. Asian J. Water Environ. Pollut. 11(3), 47–54 (2014)
A.S. NorTek, ADV Operational Manual (Vollen, Nortek AS, 1996)
S. Das, R. Das, A. Mazumdar, Velocity profile measurement technique for scour using ADV, in International Conference of Testing and Measurement: Techniques and Applications (TMTA), (Taylor & Francis Group, London, 2015), pp. 249–252