地形突变条件下异重流运动失稳规律
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摘要
由于目前异重流失稳研究相对匮乏,而其研究又对延长水库寿命和优化调度运行具有重要意义。采用Mike3建立三维异重流数学模型,包括水动力学模型、紊流模型和泥沙输移扩散方程,并采用水槽试验对该模型进行验证,结果表明异重流泥沙质量浓度分布实测值与模拟值吻合良好。以紫坪铺水库为例,采用该模型研究了异重流在地形突变条件下的运动失稳规律,分析水库底部障碍物和断面突扩对异重流运动规律的影响,得出这两种情形下的异重流失稳判别条件。底部障碍物情形的失稳判别条件为:(1)异重流运动速度减缓;(2)异重流中泥沙质量浓度降低;(3)前锋及异重流厚度减小。断面突扩情形的失稳判别条件为:(1)异重流运动速度减缓;(2)异重流中泥沙质量浓度的垂向分布由类似抛物线分布变为类似对数分布;(3)异重流厚度减小。
The instability principles of density current are less studied at present,but they are significant to the life-span extension and the optimal operation of reservoirs. Mike3 was used to construct the three-dimensional numerical model for density current,which includes a hydrodynamic model,a turbulence model and the sediment transport diffusion equation.The model was validated by a flume experiment and the results show that the modeled sediment concentration agrees well with the measured value. Based on the model,the instability principles of turbidity current under the condition of rapidly varying topography is studied by using the Zipingpu Reservoir as an example. The influence of the bottom obstacle and the abrupt widening of the cross section on density current were analyzed and the discriminant conditions for the instability of density current are obtained for the two situations respectively. For the situation of bottom obstacle,the discriminant conditions are( 1) the velocity of the density current decreases,( 2) the sediment concentration decreases,and( 3) the thickness of the front and the density current decreases. For the situation of abrupt widening at the cross section,they are( 1) the velocity of the density current decreases,( 2) the vertical profiles of sediment concentration change from parabolic distribution to logarithmic distribution,and( 3) the thickness of the density current decreases.
The instability principles of density current are less studied at present,but they are significant to the life-span extension and the optimal operation of reservoirs. Mike3 was used to construct the three-dimensional numerical model for density current,which includes a hydrodynamic model,a turbulence model and the sediment transport diffusion equation.The model was validated by a flume experiment and the results show that the modeled sediment concentration agrees well with the measured value. Based on the model,the instability principles of turbidity current under the condition of rapidly varying topography is studied by using the Zipingpu Reservoir as an example. The influence of the bottom obstacle and the abrupt widening of the cross section on density current were analyzed and the discriminant conditions for the instability of density current are obtained for the two situations respectively. For the situation of bottom obstacle,the discriminant conditions are( 1) the velocity of the density current decreases,( 2) the sediment concentration decreases,and( 3) the thickness of the front and the density current decreases. For the situation of abrupt widening at the cross section,they are( 1) the velocity of the density current decreases,( 2) the vertical profiles of sediment concentration change from parabolic distribution to logarithmic distribution,and( 3) the thickness of the density current decreases.
引文
[1]严忠銮,安瑞冬,李嘉,等.浊度型清浑水交界面识别方法及其在水库异重流观测中的应用[J].水利水电科技进展,2013,33(6):71-75.(YAN Zhongluan,AN Ruidong,LI Jia,et al.Turbid interface identification method of turbidity currents and its application in field observation at Zipingpu Reservoir[J].Advances in Science and Technology of Water Resources,2013,33(6):71-75.(in Chinese))
[2]李书霞,夏军强,张俊华,等.水库浑水异重流潜入点判别条件[J].水科学进展,2012,23(3):363-368.(LI Shuxia,XIA Junqiang,ZHENG Junhua,et al.Prediction criterion of turbidity current formation in reservoir[J].Advances in Water Science,2012,23(3):363-368.(in Chinese))
[3]高亚军,陆永军,许慧.小浪底水库异重流对库区河床冲淤的影响[J].河海大学学报(自然科学版),2009,37(2):240-244.(GAO Yajun,LU Yongjun,XU Hui.Effect of density currents in Xiaolangdi Reservoir on riverbed erosion and deposition[J].Journal of Hohai University(Natural Sciences),2009,37(2):240-244.(in Chinese))
[4]李永,李嘉,安瑞冬.水沙两相流ASM模型在浑水异重流计算中的应用及模型试验研究[J].四川大学学报(工程科学版),2009,41(4):102-108.(LI Yong,LI Jia,AN Ruidong.The application of water-sediment two phase flow ASM model in the density current of turbid water and related model test study[J].Journal of Sichuan University(Engineering Science Edition),2009,41(4):102-108.(in Chinese))
[5]RUI DONG A N,JIA L I.Characteristic analysis of the plunging of turbidity currents[J].Jounal of Hydrodynamics:Series B,2010,22(2):274-282.
[6]曾曾,李嘉,安瑞冬,等.低含沙量异重流运动规律及其对水温分布的影响[J].水动力学研究与进展:A辑,2016,31(3):346-354.(ZENG Ceng,LI Jia,AN Ruidong,et al.The motion law of the density current with low sediment content and influence on water temperature distribution[J].Chinese Journal of Hydrodynamics,2016,31(3):346-354.(in Chinese))
[7]MAXWORTHY T.Experiments on gravity currents propagating downslopes:part 2 the evolution of a fixed volume of fluid released fromclosed locks into a long,open channel[J].Journal of Fluid Mechanics,2010,647:27-46.
[8]林挺.层结水体中异重流沿坡运动的试验研究[D].杭州:浙江大学,2016.
[9]解岳,李璇,孙昕.出水口位置对异重流运动及泥沙分布的影响[J].水资源保护,2017,33(6):114-120.(XIE Yue,LI Xuan,SUN Xin.Influence of different outlet positions on density currents movements and sediment distributions[J].Water Resources Protection,2017,33(6):114-120.(in Chinese))
[10]朱超,邱秀云,严跃成.垂向异重流式水沙分离鳃水沙分离机理浅析[J].水利水电科技进展,2009,29(5):20-23.(ZHU Chao,QIU Xiuyun,YAN Yaocheng.Analysis of mechanism of vertical-component density flow watersediment separation device[J].Advances in Science and Technology of Water Resources,2009,29(5):20-23.(in Chinese))
[11]周磊,安瑞冬,谭升魁,等.水库异重流淤积成因分析及前锋运动规律[J].水利水电科技进展,2012,32(2):6-10.(ZHOU Lei,AN Ruidong,TAN Shengkui,et al.Study on reservoir sedimentation caused by turbidity currents and experimental study on front movement[J].Advances in Science and Technology of Water Resources,2012,32(2):6-10.(in Chinese))
[12]DAI A.Experiments on gravity currents propagating on different bottom slopes[J].Journal of Fluid Mechanics,2013,731(3):117-141.
[13]OEHY C D,SCHLEISS A J.Control of turbidity currents in reservoirs by solid and permeable obstacles[J].Journal of Hydraulic Engineering,2007,133(6):637-648.
[14]范家骅.浑水异重流槽宽突变时的局部掺混[J].水利学报,2005,36(1):1-8.(FAN Jiahua.Local entrainment of turbid density current in width abrupt changed channel[J].Journal of Hydraulic Engineering,2005,36(1):1-8.(in Chinese))
[15]王增辉,夏军强,李涛,等.水库异重流一维水沙耦合模型[J].水科学进展,2015,26(1):74-82.(WANG Zenghui,XIA Junqiang,LI Tao,et al.One-dimensional coupled model for predicting turbidity currents in reservoirs[J].Advances in Water Science,2015,26(1):74-82.(in Chinese))
[16]GUO Y,ZHANG Z,SHI B.Numerical simulation of gravity current descending a slope into a linearly stratified environment[J].Journal of Hydraulic Engineering,2014,140(12).DOJ:04014061.
[17]谭升魁,王锐,安瑞冬,等.基于组分输运模型和RNG k-ε模型的浑水异重流数学模型研究及其应用[J].四川大学学报(工程科学版),2011,43(增刊1):48-53.(TAN Shengkui,WANG Rui,AN Ruidong,et al.Research and application of numerical model of turbidity currents based on species transport model and RNG k-εmodel[J].Journal of Sichuan University(Engineering Science Edition),2011,43(Sup1):48-53.(in Chinese))
[18]BIRMAN V K,BATTANDIER B A,MEIBURG E,et al.Lock exchange flows in sloping channels[J].Journal of Fluid Mechanics,2007,577:53-77.
[19]BIRMAN V K,MEIBURG E,UNGARISH M.On gravity currents in stratified ambient[J].Physics of Fluids,2007,19(8):425-441.
[20]DAI A,OZDEMIR C E,CANTERO M I,et al.Gravity currents from instantaneous sources down a slope[J].Journal of Hydraulic Engineering,2012,138(3):237-246.
[21]DAI A.Gravity currents propagating on sloping boundaries[J].Journal of Hydraulic Engineering,2013,139(6):593-601.
[22]NASR-AZADANI M M,MEIBURG E.Turbins:an immersed boundary,Navier-Stokes code for the simulation of gravity and turbidity currents interacting with complex topographies[J].Computers&Fluids,2011,45(1):14-28.
[23]胡念三.香溪河河口温差异重流三维数值模拟研究[D].宜昌:三峡大学,2013.
[2]李书霞,夏军强,张俊华,等.水库浑水异重流潜入点判别条件[J].水科学进展,2012,23(3):363-368.(LI Shuxia,XIA Junqiang,ZHENG Junhua,et al.Prediction criterion of turbidity current formation in reservoir[J].Advances in Water Science,2012,23(3):363-368.(in Chinese))
[3]高亚军,陆永军,许慧.小浪底水库异重流对库区河床冲淤的影响[J].河海大学学报(自然科学版),2009,37(2):240-244.(GAO Yajun,LU Yongjun,XU Hui.Effect of density currents in Xiaolangdi Reservoir on riverbed erosion and deposition[J].Journal of Hohai University(Natural Sciences),2009,37(2):240-244.(in Chinese))
[4]李永,李嘉,安瑞冬.水沙两相流ASM模型在浑水异重流计算中的应用及模型试验研究[J].四川大学学报(工程科学版),2009,41(4):102-108.(LI Yong,LI Jia,AN Ruidong.The application of water-sediment two phase flow ASM model in the density current of turbid water and related model test study[J].Journal of Sichuan University(Engineering Science Edition),2009,41(4):102-108.(in Chinese))
[5]RUI DONG A N,JIA L I.Characteristic analysis of the plunging of turbidity currents[J].Jounal of Hydrodynamics:Series B,2010,22(2):274-282.
[6]曾曾,李嘉,安瑞冬,等.低含沙量异重流运动规律及其对水温分布的影响[J].水动力学研究与进展:A辑,2016,31(3):346-354.(ZENG Ceng,LI Jia,AN Ruidong,et al.The motion law of the density current with low sediment content and influence on water temperature distribution[J].Chinese Journal of Hydrodynamics,2016,31(3):346-354.(in Chinese))
[7]MAXWORTHY T.Experiments on gravity currents propagating downslopes:part 2 the evolution of a fixed volume of fluid released fromclosed locks into a long,open channel[J].Journal of Fluid Mechanics,2010,647:27-46.
[8]林挺.层结水体中异重流沿坡运动的试验研究[D].杭州:浙江大学,2016.
[9]解岳,李璇,孙昕.出水口位置对异重流运动及泥沙分布的影响[J].水资源保护,2017,33(6):114-120.(XIE Yue,LI Xuan,SUN Xin.Influence of different outlet positions on density currents movements and sediment distributions[J].Water Resources Protection,2017,33(6):114-120.(in Chinese))
[10]朱超,邱秀云,严跃成.垂向异重流式水沙分离鳃水沙分离机理浅析[J].水利水电科技进展,2009,29(5):20-23.(ZHU Chao,QIU Xiuyun,YAN Yaocheng.Analysis of mechanism of vertical-component density flow watersediment separation device[J].Advances in Science and Technology of Water Resources,2009,29(5):20-23.(in Chinese))
[11]周磊,安瑞冬,谭升魁,等.水库异重流淤积成因分析及前锋运动规律[J].水利水电科技进展,2012,32(2):6-10.(ZHOU Lei,AN Ruidong,TAN Shengkui,et al.Study on reservoir sedimentation caused by turbidity currents and experimental study on front movement[J].Advances in Science and Technology of Water Resources,2012,32(2):6-10.(in Chinese))
[12]DAI A.Experiments on gravity currents propagating on different bottom slopes[J].Journal of Fluid Mechanics,2013,731(3):117-141.
[13]OEHY C D,SCHLEISS A J.Control of turbidity currents in reservoirs by solid and permeable obstacles[J].Journal of Hydraulic Engineering,2007,133(6):637-648.
[14]范家骅.浑水异重流槽宽突变时的局部掺混[J].水利学报,2005,36(1):1-8.(FAN Jiahua.Local entrainment of turbid density current in width abrupt changed channel[J].Journal of Hydraulic Engineering,2005,36(1):1-8.(in Chinese))
[15]王增辉,夏军强,李涛,等.水库异重流一维水沙耦合模型[J].水科学进展,2015,26(1):74-82.(WANG Zenghui,XIA Junqiang,LI Tao,et al.One-dimensional coupled model for predicting turbidity currents in reservoirs[J].Advances in Water Science,2015,26(1):74-82.(in Chinese))
[16]GUO Y,ZHANG Z,SHI B.Numerical simulation of gravity current descending a slope into a linearly stratified environment[J].Journal of Hydraulic Engineering,2014,140(12).DOJ:04014061.
[17]谭升魁,王锐,安瑞冬,等.基于组分输运模型和RNG k-ε模型的浑水异重流数学模型研究及其应用[J].四川大学学报(工程科学版),2011,43(增刊1):48-53.(TAN Shengkui,WANG Rui,AN Ruidong,et al.Research and application of numerical model of turbidity currents based on species transport model and RNG k-εmodel[J].Journal of Sichuan University(Engineering Science Edition),2011,43(Sup1):48-53.(in Chinese))
[18]BIRMAN V K,BATTANDIER B A,MEIBURG E,et al.Lock exchange flows in sloping channels[J].Journal of Fluid Mechanics,2007,577:53-77.
[19]BIRMAN V K,MEIBURG E,UNGARISH M.On gravity currents in stratified ambient[J].Physics of Fluids,2007,19(8):425-441.
[20]DAI A,OZDEMIR C E,CANTERO M I,et al.Gravity currents from instantaneous sources down a slope[J].Journal of Hydraulic Engineering,2012,138(3):237-246.
[21]DAI A.Gravity currents propagating on sloping boundaries[J].Journal of Hydraulic Engineering,2013,139(6):593-601.
[22]NASR-AZADANI M M,MEIBURG E.Turbins:an immersed boundary,Navier-Stokes code for the simulation of gravity and turbidity currents interacting with complex topographies[J].Computers&Fluids,2011,45(1):14-28.
[23]胡念三.香溪河河口温差异重流三维数值模拟研究[D].宜昌:三峡大学,2013.