泥沙异重流与环境物质交换经验式对比
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摘要
采用异重流层平均水沙耦合数学模型,模拟开闸式和恒定入流式泥沙异重流水槽实验,对比分析异重流与环境之间物质交换经验式的适应性和不确定性。考虑4个水卷吸经验式:ew59、ew86、ew87和ew01,5个泥沙侵蚀经验式:E_s77、E_s86、E_s87、E_s93和E_s04。数值研究表明:水卷吸对于水槽异重流影响较小,应用综合考虑底床摩擦和剪切不稳定的ew经验式时模拟结果较好;开闸式异重流对床面侵蚀能力有限。对于恒定入流式异重流,应用E_s87和E_s93侵蚀经验式计算所得淤积厚度与实测值吻合较好,可能是率定时综合考虑了异重流实验数据。
In this paper,a layer-averaged fully coupled model is applied for simulating both laboratory lock-release and constant-flux turbidity currents with the aim of analyzing the applicability and uncertainties of empirical relations for the water and sediment entrainment process.For this purpose,the performance of four empirical formulae(i.e.,ew59,ew86,ew87 and ew01) for the water entrainment and five(i.e.,E_s77,E_s86,E_s87,E_s93 and E_s04) for the sediment erosion are compared.The following understandings are drawn from numerical case studies.The water entrainment has mild effect on small-scale turbidity currents,though simulation results with the ew01 relation are slightly better than those by others.It might be due to the fact that the ew01 relation has taken into account of the effects of both bottom and upper interface resistances.Lock-exchange turbidity currents are mainly depositional and thus less sensitive to the choice of erosion relations.For constant-flux turbidity currents,the E_s87 and E_s93 relations appear to perform best.This must be attributed to the fact only these two erosion relations have been calibrated using experimental turbidity current data.This study should help further studies for developing and calibrating empirical relations of mass exchange for turbidity currents.
In this paper,a layer-averaged fully coupled model is applied for simulating both laboratory lock-release and constant-flux turbidity currents with the aim of analyzing the applicability and uncertainties of empirical relations for the water and sediment entrainment process.For this purpose,the performance of four empirical formulae(i.e.,ew59,ew86,ew87 and ew01) for the water entrainment and five(i.e.,E_s77,E_s86,E_s87,E_s93 and E_s04) for the sediment erosion are compared.The following understandings are drawn from numerical case studies.The water entrainment has mild effect on small-scale turbidity currents,though simulation results with the ew01 relation are slightly better than those by others.It might be due to the fact that the ew01 relation has taken into account of the effects of both bottom and upper interface resistances.Lock-exchange turbidity currents are mainly depositional and thus less sensitive to the choice of erosion relations.For constant-flux turbidity currents,the E_s87 and E_s93 relations appear to perform best.This must be attributed to the fact only these two erosion relations have been calibrated using experimental turbidity current data.This study should help further studies for developing and calibrating empirical relations of mass exchange for turbidity currents.
引文
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[2]范家骅.浑水异重流水量掺混系数的研究[J].水利学报,2011(1):19-26.(FAN J H.Studies on water entrainment coefficient of turbid density currents[J].Journal of Hydraulic Engineering,2011(1):19-26.(in Chinese))
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[7]SMITH J D,MCLEAN S R.Spatially averaged flow over a wavy surface[J].Journal of Geophysical Research,1977,82(12):1735-1746.
[8]FUKUSHIMA Y,PARKER G,PANTIN H M.Prediction of ignitive turbidity currents in Scripps Submarine Canyon[J].Marine Geology,1985,67(1):55-81.
[9]WRIGHT S,PARKER G.Flow resistance and suspended load in sand-bed rivers:simplified stratification model[J].Journal of Hydraulic Engineering,2004,130(8):796-805.
[10]GARCIA M,PARKER G.Experiments on the entrainment of sediment into suspension by a dense bottom current[J].Journal of Geophysical Research:Oceans,1993,98(C3):4793-4807.
[11]YI A,IMRAN J.The role of erosion rate formulation on the ignition and subsidence of turbidity current[C]//Proceedings of the 4th Symposium in River,Coastal and Estuarine Morphydynamics.London:CRC Press,Taylor&Francis,2006:543-552.
[12]TRAER M,HILLEY G E,FILDANI A,et al.The sensitivity of turbidity currents to mass and momentum exchanges between these underflows and their surroundings[J].Journal of Geophysical Research:Earth Surface,2012,117(F1):1-16.
[13]HU P,PHTZ T,HE Z.Is it appropriate to model turbidity currents with the three-equation model?[J].Journal of Geophysical Research:Earth Surface,2015,120(7):1153-1170.
[14]HU P,CAO Z.Fully coupled mathematical modeling of turbidity currents over erodible bed[J].Advances in Water Resources,2009,32(1):1-15.
[15]MULDER T,ALEXANDER J.Abrupt change in slope causes variation in the deposit thickness of concentrated particle-driven density currents[J].Marine Geology,2001,175:221-235.
[16]KUBO Y.Experimental and numerical study of topographic effects on deposition from two-dimensional,particle-driven density currents[J].Sedimentary Geology,2004,164(3/4):311-326.
[17]BONNECAZE R T,LISTER J R.Particle-driven gravity currents down planar slopes[J].Journal of Fluid Mechanics,1999,390:75-91.
[18]ALEXANDER J,MULDER T.Experimental quasi-steady density currents[J].Marine Geology,2002,186:195-210.
[19]GARCIA M,PARKER G.Experiments on hydraulic jumps in turbidity currents near a Canyon-Fan Transition[J].Science,1989,245(4916):393-396.
[2]范家骅.浑水异重流水量掺混系数的研究[J].水利学报,2011(1):19-26.(FAN J H.Studies on water entrainment coefficient of turbid density currents[J].Journal of Hydraulic Engineering,2011(1):19-26.(in Chinese))
[3]PARKER G,FUKUSHIMA Y,PANTIN H M.Self-accelerating turbidity currents[J].Journal of Fluid Mechanics,1986,171:145-181.
[4]PARKER G,GARCIA M,FUKUSHIMA Y,et al.Experiments on turbidity currents over an erodible bed[J].Journal of Hydraulic Research,1987,25(1):123-147.
[5]DALLIMORE C,IMBERGER J,ISHIKAWA T.Entrainment and turbulence in saline underflow in Lake Ogawara[J].Journal of Hydraulic Engineering,2001,127(11):937-948.
[6]范家骅.异重流泥沙淤积的分析[J].中国科学:数学,1980(1):82-89.(FAN J H.The analysis of the turbidity current sedimentation[J].Science China:Mathematics,1980(1):82-89.(in Chinese))
[7]SMITH J D,MCLEAN S R.Spatially averaged flow over a wavy surface[J].Journal of Geophysical Research,1977,82(12):1735-1746.
[8]FUKUSHIMA Y,PARKER G,PANTIN H M.Prediction of ignitive turbidity currents in Scripps Submarine Canyon[J].Marine Geology,1985,67(1):55-81.
[9]WRIGHT S,PARKER G.Flow resistance and suspended load in sand-bed rivers:simplified stratification model[J].Journal of Hydraulic Engineering,2004,130(8):796-805.
[10]GARCIA M,PARKER G.Experiments on the entrainment of sediment into suspension by a dense bottom current[J].Journal of Geophysical Research:Oceans,1993,98(C3):4793-4807.
[11]YI A,IMRAN J.The role of erosion rate formulation on the ignition and subsidence of turbidity current[C]//Proceedings of the 4th Symposium in River,Coastal and Estuarine Morphydynamics.London:CRC Press,Taylor&Francis,2006:543-552.
[12]TRAER M,HILLEY G E,FILDANI A,et al.The sensitivity of turbidity currents to mass and momentum exchanges between these underflows and their surroundings[J].Journal of Geophysical Research:Earth Surface,2012,117(F1):1-16.
[13]HU P,PHTZ T,HE Z.Is it appropriate to model turbidity currents with the three-equation model?[J].Journal of Geophysical Research:Earth Surface,2015,120(7):1153-1170.
[14]HU P,CAO Z.Fully coupled mathematical modeling of turbidity currents over erodible bed[J].Advances in Water Resources,2009,32(1):1-15.
[15]MULDER T,ALEXANDER J.Abrupt change in slope causes variation in the deposit thickness of concentrated particle-driven density currents[J].Marine Geology,2001,175:221-235.
[16]KUBO Y.Experimental and numerical study of topographic effects on deposition from two-dimensional,particle-driven density currents[J].Sedimentary Geology,2004,164(3/4):311-326.
[17]BONNECAZE R T,LISTER J R.Particle-driven gravity currents down planar slopes[J].Journal of Fluid Mechanics,1999,390:75-91.
[18]ALEXANDER J,MULDER T.Experimental quasi-steady density currents[J].Marine Geology,2002,186:195-210.
[19]GARCIA M,PARKER G.Experiments on hydraulic jumps in turbidity currents near a Canyon-Fan Transition[J].Science,1989,245(4916):393-396.