Alluvial channel hydrodynamics around tandem piers with downward seepage
Rutuja CHAVAN1, Wenxin HUAI2, Bimlesh KUMAR3()
1. Department of Civil Engineering, Maulana Azad National Institute of Technology Bhopal, Bhopal, Madhya Pradesh 462003, India 2. Department of Harbor, School of Water Resources and Hydropower Engineering, Wuhan University, Wuhan 430072, China 3. Department of Civil Engineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
In this paper, we report the turbulent flow structures and the scour geometry around two piers with different diameters. An experiment was conducted on a non-uniform sand bed with two types of tandem arrangements, namely, pier (T1) with a 75 mm front and 90 mm rear, and pier (T2) with a 90 mm front and 75 mm rear, with and without-seepage flows, respectively. A strong wake region was observed behind the piers, but the vortex strength diminished with downward seepage. Streamwise velocity was found to be maximum near the bed downstream of the piers and at the edge of the scour hole upstream of the piers. Quadrant analysis was used to recognize the susceptible region for sediment entrainment and deposition. Upstream of the piers near the bed, the moments, turbulent kinetic energy (TKE), and TKE fluxes were found to decrease with downward seepage, in contrast to those in a plane mobile bed without piers. The reduction percentages of scour depth at the rear pier compared with the front one were approximately 40% for T1 and 60% for T2. Downward seepage also resulted in restrained growth of scouring with time.
75 mm front and 90 mm rear (T1) and 90 mm front and 75 mm rear (T2)
0.118
0.27
0 (Q1) 10 (qs1) 15 (qs2)
2
0.121
0.281
0 (Q2) 10 (qs1) 15 (qs2)
3
0.123
0.293
0 (Q3) 10 (qs1) 15 (qs2)
4
0.126
0.302
0 (Q4) 10 (qs1) 15 (qs2)
5
0.129
0.31*
0 (Q5) 10 (qs1) 15 (qs2)
Tab.1
Fig.4
Fig.5
Fig.6
Fig.7
Fig.8
Fig.9
Fig.10
Fig.11
Fig.12
experimental conditions
Strouhal number
arrangement T1 (75–90 mm)
arrangement T2 (90–75 mm)
near free surface
near bed
near free surface
near bed
no seepage
0.26
0.18
0.24
0.16
10% seepage
0.21
0.15
0.20
0.13
15% seepage
0.18
0.13
0.16
0.11
Tab.2
Fig.13
Fig.14
Fig.15
Fig.16
Fig.17
Fig.18
1
B W Melville. Local Scour at Bridge Sites. Auckland: The University of Auckland, 1975
2
R Ettema. Scour at bridge piers. Dissertation for the Doctoral Degree. Auckland: The University of Auckland, 1980
3
A Qadar. The vortex scour mechanism at bridge piers. In: Proceedings of the Institution of Civil Engineers Part Research & Theory. Aligarh, 1981
4
Y. M Chiew,. Local scour at bridge piers. Dissertation for the Doctoral Degree. Auckland: University of Auckland, 1984
5
E V Richardson, S R Davis. Evaluating Scour at Bridges. 4th ed. Washington, D.C.: Federal Highway Administration, 2001
6
R Pasiok, E Stilger-Szydło. Sediment particles and turbulent flow simulation around bridge piers. Archives of Civil and Mechanical Engineering, 2010, 10(2): 67–79 https://doi.org/10.1016/S1644-9665(12)60051-X
7
B W Melville, S E Coleman. Bridge Scour. Lone Tree, CO: Water Resources Publications, 2000
8
E Izadinia, M Heidarpour, A J Schleiss. Investigation of turbulence flow and sediment entrainment around a bridge pier. Stochastic Environmental Research and Risk Assessment, 2013, 27(6): 1303–1314 https://doi.org/10.1007/s00477-012-0666-x
9
B Ataie-Ashtiani, Z Baratian-Ghorghi, A A Beheshti. Experimental investigation of clear-water local scour of compound piers. Journal of Hydraulic Engineering, 2010, 136(6): 343–351 https://doi.org/10.1061/(ASCE)0733-9429(2010)136:6(343)
10
M Beg. Characteristics of developing scour holes around two piers placed in transverse arrangement. In: Scour and Erosion. California, 2010
11
M Salim, J S Jones. Scour around exposed pile foundations. In: North American Water and Environment Congress & Destructive Water. California: ASCE, 1996
N Mahjoub Said, H Mhiri, H Bournot, G Le Palec. Experimental and numerical modelling of the three dimensional incompressible flow behaviour in the near wake of circular cylinders. Journal of Wind Engineering and Industrial Aerodynamics, 2008, 96(5): 471–502 https://doi.org/10.1016/j.jweia.2007.12.001
B Ataie-Ashtiani, A Aslani-Kordkandi. Flow field around single and tandem piers. Flow, Turbulence and Combustion, 2013, 90(3): 471–490 https://doi.org/10.1007/s10494-012-9427-7
16
A Okajima, S Yasui, T Kiwata, S Kimura. Flow-induced streamwise oscillation of two circular cylinders in tandem arrangement. International Journal of Heat and Fluid Flow, 2007, 28(4): 552–560 https://doi.org/10.1016/j.ijheatfluidflow.2007.04.015
M Elhimer, G Harran, Y Hoarau, S Cazin, M Marchal, M Braza. Coherent and turbulent processes in the bistable regime around a tandem of cylinders including reattached flow dynamics by means of high-speed PIV. Journal of Fluids and Structures, 2016, 60: 62–79 https://doi.org/10.1016/j.jfluidstructs.2015.10.008
19
H D Sharma, A S Chawla. Manual of Canal Lining. Technical Report No. l4. Central Board of Irrigation and Power New Delhi. 1975
20
K Krishnamurthy, S Rao. Theory and experiment in canal seepage estimation using radioisotopes. Journal of Hydrology (Amsterdam), 1969, 9(3): 277–293 https://doi.org/10.1016/0022-1694(69)90022-5
21
C Berenbrock. Stream Flow Gains and Losses in the Lower Boise River Basin, Idaho, 1996-97. Boise: US Department of the Interior, US Geological Survey, 1999
22
K K Tanji, N C Kielen. Agricultural Drainage Water Management in Arid and Semi-Arid Areas. Rome, UN: FAO, 2002
23
K D Kinzli, M Martinez, R Oad, A Prior, D Gensler. Using an ADCP to determine canal seepage loss in an irrigation district. Agricultural Water Management, 2010, 97(6): 801–810 https://doi.org/10.1016/j.agwat.2009.12.014
24
C A Martin, T K Gates. Uncertainty of canal seepage losses estimated using flowing water balance with acoustic Doppler devices. Journal of Hydrology (Amsterdam), 2014, 517: 746–761 https://doi.org/10.1016/j.jhydrol.2014.05.074
25
Y Lu, Y M Chiew, N S Cheng. Review of seepage effects on turbulent open channel flow and sediment entrainment. Journal of Hydraulic Research, 2008, 46(4): 476–488 https://doi.org/10.3826/jhr.2008.2942
S Francalanci, G Parker, L Solari. Effect of seepage-induced nonhydrostatic pressure distribution on bed-load transport and bed morphodynamics. Journal of Hydraulic Engineering, 2008, 134(4): 378–389 https://doi.org/10.1061/(ASCE)0733-9429(2008)134:4(378)
29
M Qi, Y M Chiew, J H Hong. Suction effects on bridge pier scour under clear-water conditions. Journal of Hydraulic Engineering, 2013, 139(6): 621–629 https://doi.org/10.1061/(ASCE)HY.1943-7900.0000711
30
R Chavan, A Sharma, B Kumar. Effect of downward seepage on turbulent flow characteristics and bed morphology around bridge piers. Journal of Marine Science and Application, 2017, 16(1): 60–72 https://doi.org/10.1007/s11804-017-1394-x
V Deshpande, B Kumar. Turbulent flow structures in alluvial channels with curved cross‐sections under conditions of downward seepage. Earth Surface Processes and Landforms, 2016, 41(8): 1073–1087 https://doi.org/10.1002/esp.3889
37
H Tennekes, J L Lumley. A First Course in Turbulence. London: MIT Press, 1972
38
S S Lu, W W Willmarth. Measurements of the structure of the Reynolds stress in a turbulent boundary layer. Journal of Fluid Mechanics, 1973, 60(3): 481–511 https://doi.org/10.1017/S0022112073000315
39
M Cellino, U Lemmin. Influence of coherent flow structures on the dynamics of suspended sediment transport in open-channel flow. Journal of Hydraulic Engineering, 2004, 130(11): 1077–1088 https://doi.org/10.1061/(ASCE)0733-9429(2004)130:11(1077)
40
M R Raupach. Conditional statistics of Reynolds stress in rough-wall and smooth-wall turbulent boundary layers. Journal of Fluid Mechanics, 1981, 108: 363–382 https://doi.org/10.1017/S0022112081002164
41
H Maity, B S Mazumder. Contributions of burst-sweep cycles to Reynolds shear stress over fluvial obstacle marks generated in a laboratory flume. International Journal of Sediment Research, 2012, 27(3): 378–387 https://doi.org/10.1016/S1001-6279(12)60042-0
42
R Chavan, B. KumarExperimental investigation on flow and scour characteristics around tandem piers in sandy channel with downward seepage. Journal of Marine Science and Application, 2017, 16(3), 313–322
43
R Chavan, B Kumar. Prediction of scour depth and dune morphology around circular bridge piers in seepage affected alluvial channels. Environmental Fluid Mechanics, 2018, 18(4): 923–945 https://doi.org/10.1007/s10652-018-9574-z
