Journal of Hydroelectric Engineering

水力发电学报

Office Online

Included Databases

The journal is included in the following databases:
(i)Scopus,
(ii)The Chinese Science Citation Database Source Journals,
(iii)The Chinese Science Journal Abstract Database,
(iv)The Chinese Science and Technology Papers Statistics and Analysis Database,
(v)China Newspaper Subscription Guide Information Database,
(vi)Chinese Academic Journals (CD).


2019 Vol. 38, No. 9 Published: 2019-09-25

	1	A review of numerical methods for far-field modeling in dynamic soil-structure interaction systems ^Hot!
		SONG Chongmin, QU Yanling, LIU Lei, CHEN Denghong
		DOI: 10.11660/slfdxb.20190901
		Dynamic Soil-Structure Interaction (DSSI) problem is one of the most important issues in the dynamic analysis of structures. Numerical simulations are widely applied to the study of DSSI effects owing to the rapid progress in computational power and numerical schemes. In a numerical method, DSSI system is portioned into a finite domain surrounding the structures (near field) and an infinite region (far field) by either direct method or substructure method. The modeling of the near field may consider nonlinear behaviors, while the modelling of the far field must satisfy the radiation condition at infinity and allows the input from an external source in some occasions. In this paper, various numerical methods that are, in the authors’ opinion, commonly used in the DSSI analysis are reviewed.
		2019 Vol. 38 (9): 1-17 [Abstract] ( 376 ) PDF (574 KB) ( 1248 )

	18	Novel methodology of structural vibration control for hydropower house based on tuned mass damper
		ZHONG Tengfei, FENG Xin, ZHOU Jing
		DOI: 10.11660/slfdxb.20190902
		The vibration of power generating units usually causes resonances in high-order modes of the powerhouse structure of a hydropower station and threatens its safety. Aiming at this issue, a vibration control method based on the tuned mass damper (TMD) is presented. A new type of high-frequency TMD controller is designed, and tests are conducted on the vibration reduction of a two-story steel frame, focusing on the damping effect under high-frequency harmonic excitation and narrow-band sweep excitation. The results show that this controller effectively controls the high order modes of the structure and its control effect is best when TMD-3 is added, achieving an attenuation rate of peak acceleration of 94.1% at the top of the structure, and 95.6% in the first layer. As the TMD tuning frequency is lowered from the high-order modes, the damping is decreased gradually, but its effect remains satisfactory. This indicates that the new TMD tuning frequency band is wider and has a certain robustness. For wider excitation frequencies, the damping effect is the best when the tuning frequency is close to the controlled frequency, but the robustness worsens when it deviates from the controlled frequency.
		2019 Vol. 38 (9): 18-28 [Abstract] ( 182 ) PDF (954 KB) ( 448 )

	29	Opening temperature of transverse joints of arch dams and its application
		LI Qingbin, MA Rui, ZHU He, WANG Zhilin, CHEN Wenfu, YANG Ning, HU Yu
		DOI: 10.11660/slfdxb.20190903
		Behaviors of the transverse joints of an arch dam are crucial to evaluating its performance in the whole life cycle. A practically important issue is to study and control the joint characteristics through temperature control. Based on analysis of the engineering data, this paper summarizes the trends of changes in the transverse joints with different internal temperatures in the concrete of dam blocks. We define the opening temperature of a transverse joint and derive its calculation method. The results show that the opening temperature can be used as a key index of joint performance. Based on this, measures for the individualized optimization of an arch dam are provided to achieve a precise control of the opening time and opening amount of its transverse joints.
		2019 Vol. 38 (9): 29-36 [Abstract] ( 258 ) PDF (1232 KB) ( 589 )

	37	Experimental study on mix proportion of plastic concrete with clay
		WANG Xiequn, BAO Xiaoyu
		DOI: 10.11660/slfdxb.20190904
		Experimental tests on plastic concrete are conducted in this study by using engineering analogy method and comparing 22 sets of different mixing proportion under its performance requirements provided by the designer. We focus on the concrete’s design schemes of single clay mixing and the influence of raw materials and age on the performance, using four evaluation indexes, i.e., cubic compressive strength, elasticity modulus, triaxial compressive strength, and permeability coefficient. Results show that all of these schemes can meet the engineering requirements. And when the clay content is within a certain range (< 80 kg/m3), concrete strength is reduced with an increase in it while elastic modulus varies in the opposite trend; when the content is bigger than 80 kg/m3, a further increase causes elastic modulus to fluctuate within a certain range but no significant change in concrete strength. The concrete strength and elastic modulus are positively correlated with the cement content, while negatively correlated with the bentonite content. Under triaxial confining pressure, the two sets of optimal mix proportion feature a compressive strength increased by 19% on average at the 90 d age compared to the 28 d age, and their permeability coefficients at 90 d age are lower than those at 28 d age.
		2019 Vol. 38 (9): 37-43 [Abstract] ( 185 ) PDF (408 KB) ( 438 )

	44	Evaluation of land use/cover change and land use grade in Qaidam basin, China
		XU Guoyin, WANG Zhongjing, HU Zhidan, ZHANG Jinxu
		DOI: 10.11660/slfdxb.20190905
		Based on the European Space Agency (ESA) Climate Change Initiative (CCI) Land cover products, this paper examines the land use/cover data of four years (2000, 2005, 2010 and 2015) for the Qaidam basin, and calculates the land use/cover type change matrix. Then, using the matrix, we evaluate the land use transfer priority direction and formulate a new land use grade index. The results show that in this basin, the main land use types were grassland and unused land, accounting for 51.6% and 44.9% of the basin, respectively. Water area, cropland and forestland were in a decreasing order of land cover proportion, and the proportion of residential land was the smallest. During the past 15 years, cropland, grassland and residential land areas have been increased, while unused land decreased, both in a monotonous trend. Of the transformation between different land use/cover types, the one between grassland and unused land was the largest, and it occurred mainly in the southwest of the basin and the Qilian mountains. The land use grade index of the Qaidam basin shows a continuing growth but in a small range, which means the change in land use/cover has been stable globally and sharp locally. The study provides an approach for land resource assessment, land use planning and sustainable management.
		2019 Vol. 38 (9): 44-55 [Abstract] ( 216 ) PDF (4426 KB) ( 521 )

	56	Dam break risk of reservoir under impact of landslide dam break floods
		LI Ping, HUANG Yuefei, YU Haiying, LI Binge
		DOI: 10.11660/slfdxb.20190906
		To study the impact of landslide dam break floods on the risk of a downstream reservoir, a Bayesian network method and Monte Carlo simulations are used to calculate the conditional probability of reservoir dam break under the combined action of natural floods and landslide dam break floods, and the risk of reservoir dam break is evaluated. A case study of the Houziyan reservoir shows that at its normal water stage, the conditional probability of dam break caused only by natural floods is low or the risk is low, while the one caused only by landslide dam break floods is greater than 0.3. And the risk is increased by tens of thousands of times under the combined action of two types of floods.
		2019 Vol. 38 (9): 56-63 [Abstract] ( 162 ) PDF (437 KB) ( 695 )

	64	Dynamic control of reservoir operating stage considering dynamic flood forecast period
		ZHANG Yanke, ZHANG Jiaxin, YU Hongjie, JI Changming
		DOI: 10.11660/slfdxb.20190907
		To make full use of water resources and improve flood utilization under the condition of reasonable assessment of flood control risk, dynamic control of reservoir stage is examined through a case study of the Pankou reservoir. First, we optimize the flood season stage of a reservoir by assuming that its flood storage capacity reserved for the downstream reservoir has an overlapping space, and then use a forecast pre-discharge method to construct a model for estimating the upper limit of the dynamic control domain of reservoir stage. Finally, we focus on the dynamic change in flood forecast period and obtain the dynamic control domain based on risk analysis. Calculations show that in flood season, the reservoir stage can be raised up from 347.60 m to 350.50 m, and its corresponding dynamic stage control domain is [350.50, 351.40] m when considering a range of the flood forecast period of [3, 6] h with an interval of 0.5 h. And the resulting increase in power generation is 19 million kW?h to 25 million kW?h. The study indicates that to consider both flood control safety and water storage comprehensively, the schemes presented in this study are reasonable and feasible to control the stage of the Pankou reservoir in flood season.
		2019 Vol. 38 (9): 64-72 [Abstract] ( 228 ) PDF (378 KB) ( 554 )

	73	Simulations of future water temperature of Nuozhadu reservoir with newly developed WRF lake model
		WANG Fushan, SUN Ting, ZHU Dejun, LU Ji, NI Guangheng
		DOI: 10.11660/slfdxb.20190908
		Water temperature of a reservoir has a great impact on riverine ecology and environment and even local climate. In the context of future climate change, the response of reservoir water temperature has attracted broad attention. In this paper, a newly developed lake model in the Weather Research and Forecasting system (WRF-rLake afterwards) is applied to simulations of the Nuozhadu reservoir, focusing on the trends in its water temperature under different future climates (RCP2.6 and RCP8.5). We found out that the water temperature shows an increasing trend under different future climate conditions, and that the responses of surface water temperature to climate change are more significant than those of deep water. By the end of the 21st century, the surface water of the reservoir will rise by 4 °C at most and the deep water by about 0.8 °C.
		2019 Vol. 38 (9): 73-82 [Abstract] ( 281 ) PDF (3150 KB) ( 427 )

	83	3D Eulerian-Lagrangian shallow water model using spectral element method
		YANG Fei, FU Xudong
		DOI: 10.11660/slfdxb.20190909
		A 3D hydrodynamic model that calculates advection terms with an Eulerian-Lagrangian method (ELM) can maintain numerical stability at large time steps, while its linear interpolation generates a significant amount of additional numerical resistance, restricting its application in river engineering. Spectral element method (SEM) is a high-order method suitable for irregular domain calculations. This paper uses SEM to replace linear interpolation with polynomial interpolation in vertical direction, and develops a new 3D shallow water model by combining with ELM. Numerical experiment on open-channel flow shows that this 3D model, taking advantage of the spectral element method and ELM, is capable of breaking through the Courant number constraint on its time steps, and eliminates most of the numerical resistance of a classical ELM, thus improving its accuracy by an order of magnitude.
		2019 Vol. 38 (9): 83-90 [Abstract] ( 207 ) PDF (1407 KB) ( 352 )

	91	Hydrodynamic performance analysis of semi-submersible multi-body wave power plant
		HU Yuan, YANG Shaohui, HE Hongzhou, CHEN Hu, ZHENG Songgen, ZHANG Di
		DOI: 10.11660/slfdxb.20190910
		To alleviate energy crisis and environmental degradation and enhance the development and use of renewable energy, this study develops a numerical model of a semi-submersible multi-floating body wave power plant through combining wave energy conversion technologies of point absorption and raft type. The device is mainly composed of a central floating platform, an array of oscillating floats, a hydraulic system, and structure connecting floats to the platform, and collects wave energy from the oscillating floats on the sea surface. To improve its collecting efficiency, we numerically simulate and examine its energy conversion using AQWA hydrodynamic simulations, and analyze the frequency domain responses of a single float with different values of parameters such as the mass, size, and structure of the floats. And a detailed analysis is made on the time domain responses of a single float and the whole device under sea conditions of wave height of 1 m and wave periods of 5 s and 3 s. The results show that the geometry of the underwater part of the float has a great influence on its added mass and wave excitation force, and that a cylindrical float of 2 m in diameter features larger amplitude of vertical oscillations. This suggests that in the condition of low wave frequencies, the floats with such a design can capture wave energy closer to the maximum extent, thereby improving overall efficiency. For the floats working at high wave frequencies, they should have a conical shape, the diameter increased appropriately, and the weight reduced so as to capture more wave energy. By optimizing float structure, the energy collection efficiency of the device is raised by about 95%, indicating the importance of float structure in efficiency improvement.
		2019 Vol. 38 (9): 91-101 [Abstract] ( 548 ) PDF (1169 KB) ( 959 )

	102	Influence of pipe connection between tailrace tunnels on two-stage load rejection in pumped storage power plants
		CHEN Hongchun, LUO Xiaofeng, YANG Xiuwei, YU Xiaodong, FAN Honggang
		DOI: 10.11660/slfdxb.20190911
		Pumped storage power plants usually adopt a layout of multi units sharing a common pipe system. During operation, two-stage load rejection often leads to an extremely low pressure in the draft tube and even liquid column separation. This study develops a mathematic model of hydraulic transients in such plants with a pipe connection between tailrace tunnels, and simulates the load rejection conditions using the parameters of the Xiamen pumped storage power station. We examine the mechanism of mitigating the draft tube’s low pressure by installing a connection pipe, and analyze its effect on the transients for the cases of different pipe diameters. The results show that the pipe connection between tailrace tunnels effectively improves the draft tube’s low pressure during two-stage load rejection and increasing the diameter of the pipe makes the flow in it more sensitive to the pressure difference. Thus, its effect on pressure balance between two tailrace tunnels is more evident, and the low pressure in the draft tube is significantly improved.
		2019 Vol. 38 (9): 102-110 [Abstract] ( 243 ) PDF (951 KB) ( 542 )

	111	Discussion on hydraulic oscillations of water transfer systems in pumped-storage power stations
		LIU Zirui, YANG Feng, CHENG Yongguang, WANG Qi
		DOI: 10.11660/slfdxb.20190912
		In a pumped-storage power station, complex layout of its water transfer system and frequent change in its working condition often cause hydraulic oscillations or even hydraulic resonances. This paper summarizes unstable characteristics of the flows in pump-turbines and clarifies their relationship with the hydraulic oscillations of the transfer system. First, we examine the pump-turbine working conditions for the occurrence of unsteady flows and their typical frequency ranges related to draft tube vortices, rotating stalls, unstable oscillations in the S region, rotor stator interaction, vane tip Karman vortices, etc. Then, natural frequencies of a typical water transfer system are calculated using the transfer matrix method and compared with the frequencies of unstable flows in the pump-turbine. We found out that the frequencies of draft tube vortices and rotating stalls overlap with those of the hydraulic system, indicating the possibility to cause hydraulic resonances. Finally, the forced oscillations of the transfer system are simulated with given head disturbances to draft tube flows. The results show that draft tube vortices and rotating stalls are more likely to cause hydraulic resonances, which could lead to fluctuations in the power output. Also, oscillations in the S region could induce hydraulic oscillations during transient process. On the other hand, the high frequency characteristics of rotor-stator interactions and Karman vortices could originate the structural resonances of runners but not the hydraulic resonances in water transfer systems, for they mainly affect high-frequency pressure pulsations.
		2019 Vol. 38 (9): 111-120 [Abstract] ( 253 ) PDF (1176 KB) ( 702 )