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Stochastic Simulation and Analysis of Geological Corrosion Defects in Dam foundation

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Transactions of Tianjin university 2016年第4期22卷 324-333页

作者：王超张社荣于茂 School of Civil Engineering Tianjin University State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University

Uncertainty in geological structural modeling, especially geological corrosion(a kind of karst cave), is a bottleneck that restricts the development and application of geological computer modeling and effect estimation. To solve this issue, a stochastic modeling method based on the random field theory is proposed in comparison with the deterministic geometric modeling method. Then the constraint random field modeling method and the random field modeling method without constrained parameters are compared and analyzed. A case study shows that the novel stochastic simulation method is an effective tool to describe the distribution characteristics of corrosion parameters and reflect the updated geological prospecting information. The influence of geological corrosion on the dam behavior can also be better analyzed by using the stochastic simulation method. At the same time, the unconfined random field ignores the sample location information and may lead to higher variability. Therefore, the constraint random field modeling method can provide a useful reference for the numerical analysis under complex geological conditions.

关键词： hydraulic structure computer modeling geological corrosion stochastic simulation random field theory

Numerical Prediction and Analysis of Hydraulic Characteristics of Waterfall Scene for Application to Design Control

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Transactions of Tianjin university 2017年第3期23卷 277-288页

作者： Chao Wang Sherong Zhang Yun Li Guojin Zhu Bohui Pang Xiaofang Zheng State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China School of Civil Engineering Tianjin UniversityTianjin 300072China State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai UniversityNanjing 210098China HYDROCHINA Kunming Engineering Corporation Kunming 650051China

The hydraulic characteristics of artificial waterfalls constitute an important research area for both academia and industry. As yet, the hydraulic parameters used in the hydraulic design of landscape waterfalls are not well understood for use in qualitative and quantitative analyses. Due to their complicated shapes and appearances, it remains a challenging problem to design or simulate realistic waterfall scenes. In this paper, we present a hybrid model and an efficient numerical method for simulating the hydraulic characteristics of waterfalls and investigate the critical flow in waterfall design and the adherent flow phenomenon. We fit empirical equations to predict the size and shape of different waterfall flow patterns to provide a basis for the design and construction of waterscapes in the real world. We then apply our work to an artificial waterfall in Kraal Jiang River and the results demonstrate that our model achieves desirable control qualities and good agreement in a real-world application. © 2017, Tianjin university and Springer-Verlag Berlin Heidelberg.

关键词： Buoyancy Computer simulation Numerical methods Quality control

Strong Key-Insulated Signature in the Standard Model

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Journal of Shanghai Jiaotong university(science) 2010年第6期15卷 657-661页

作者：万中美来学嘉翁健刘胜利龙宇洪璇 Department of Computer science and Engineering Shanghai Jiaotong University College of science Hohai University Department of Computer science Jinan University

The only known construction of key-insulated signature(KIS) that can be proven secure in the standard model is based on the approach of using double signing. That is,the scheme requires two signatures:a signature with a master key and a signature with the signer's secret key. This folklore construction method leads to an ineffcient scheme. Therefore it is desirable to devise an effcient KIS scheme. We present the first scheme with such a construction. Our construction derives from some variations of the Waters' signature scheme. It is computationally effcient and the signatures are short. The scheme is provably secure based on the diffculty of computational Diffe-Hellman(CDH) problem in the standard model.

关键词： key-insulated key exposure standard model bilinear pairing

Mechanistic Drifting Forecast Model for A Small Semi-Submersible Drifter Under Tide–Wind–Wave Conditions

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China Ocean Engineering 2018年第1期32卷 99-109页

作者： ZHANG Wei-na HUANG Hui-ming WANG Yi-gang CHEN Da-ke ZHANG lin Key Laboratory of Coastal Disaster and Defence Ministry of Education Hohai University College of Harbour Coastal and offshore Engineering Hohai University

Understanding the drifting motion of a small semi-submersible drifter is of vital importance regarding monitoring surface currents and the floating pollutants in coastal regions. This work addresses this issue by establishing a mechanistic drifting forecast model based on kinetic analysis. Taking tide–wind–wave into consideration, the forecast model is validated against in situ drifting experiment in the Radial Sand Ridges. Model results show good performance with respect to the measured drifting features, characterized by migrating back and forth twice a day with daily downwind displacements. Trajectory models are used to evaluate the influence of the individual hydrodynamic forcing. The tidal current is the fundamental dynamic condition in the Radial Sand Ridges and has the greatest impact on the drifting distance. However, it loses its leading position in the field of the daily displacement of the used drifter. The simulations reveal that different hydrodynamic forces dominate the daily displacement of the used drifter at different wind scales. The wave-induced mass transport has the greatest influence on the daily displacement at Beaufort wind scale 5–6; while wind drag contributes mostly at wind scale 2–4.

关键词： in situ drifting experiment mechanistic drifting forecast model tide–wind–wave coupled conditions small semi-submersible drifter daily displacement

Henstock积分问题的一个注记(英文)

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数学进展 2005年第6期34卷 741-745页

作者：叶国菊安天庆河海大学理学院南京江苏210098

本文证明了如果X是不含c0的Banach空间,f是定义在区间I0(?)Rm上取值于Banach空间X的函数,并且f在I0上Henstock可积,则总存在I0的一个非退化子区间J,使得f在J上McShane可积,从而对Kartak的一个问题作出了肯定的回答．

关键词： Pettis积分 Mcshane积分 Henstock积分

ANISOTROPIC PERMEABILITY EVOLUTION MODEL OF ROCK IN THE PROCESS OF DEFORMATION AND FAILURE

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Journal of Hydrodynamics 2012年第1期24卷 25-31页

作者： WANG Huan-ling CHU Wei-jiang HE Miao Key Laboratory of Coastal Disaster and Defence Ministry of EducationHohai UniversityNanjing 210098China Hydrochina Huadong Engineering Corporation Hangzhou 310014China Jiangsu Transportation Research Institute CO. LTDNanjing 211112China

The rock permeability is an important parameter in the studies of seepage and stress *** micro-cracks and pores can initiate and grow on a small scale and coalesce to form large-scale fractures and faults under compressive stresses,which would change the hydraulic conductivity of the rock,and therefore,the rock *** rock permeability is,therefore,closely rela-ted with the micro-cracking growing,coalescence,and macro new fracture *** article proposes a conceptual model of rock permeability evolution and a micro kinematics mechanism of micro-cracking on the basis of the basic theory of *** applicability of the established model is verified through numerical simulations of in situ tests and laboratory *** simu-lation results show that the model can accurately forecast the peak permeability evolution of brittle rock,and can well describe the macro-experimental phenomenon before the peak permeability evolution of brittle rock on a macro-scale.

关键词： rock hydraulics micro-mechanics permeability model validation

Large eddy simulation of vertical turbulent jets under JONSWAP waves

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Acta Mechanica Sinica 2011年第2期27卷 189-199页

作者： Jun Lu Ling-Ling Wang Hong-Wu Tang Hui-Chao Dai College of Water Conservancy and Hydro-power Engineering Hohai University 210098 Nanjing China Binhu Water Resource Bureaus 214011 Wuxi China

The effect of random waves on vertical plane turbulent jets is studied numerically and the mechanism behind the interaction of the jet and waves is analyzed. The large eddy simulation method is used and the σ-coordinate system is adopted. Turbulence is modeled by a dynamic coherent eddy model. The σ-coordinate transformation is introduced to map the irregular physical domain with a wavy free surface and an uneven bottom onto a regular computational domain. The fractional step method is used to solve the filtered Navier–Stokes equations. Results presented include the distribution of velocity, the decay law of the mean velocity along the jet axis, self-similar characteristics and volume flux per unit width. In particular, the role of coherent structures on the momentum transfer along the jet centerline and the jet instantaneous characteristics in JONSWAP waves are a special focus of this research. The numerical results obtained are of great theoretical importance in understanding the behavior of turbulent jets in random wave environments.

关键词： Large eddy simulation Dynamic coherent eddy model σ-coordinate Turbulent jet JONSWAP wave

The Study of Language Learning Strategies of Non-English Majors

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Sino-US English Teaching 2005年第5期2卷 36-41页

作者： Cong Zhang hohai university Changzhou Campus

This paper, from the educational and psychological point of view, explores EFL college students＇ language learning strategies in the Chinese context. The subjects under study involve 106 non-English majors from hohai university at its Changzhou Campus. The approach is used for the research through two questionnaires to investigate the learners＇ language learning strategies. In the study, it is found that students use compensation strategies most frequently, while metacognitive strategies less and social strategies the least. Findings of the present study also indicate that the different strategies are respectively emphasized for the male and female students, students of arts and science and engineering.

关键词： language learning strategies strategy classification major differences sex differences

Field observation of wave overtopping at sea dike using shore-based video images

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Journal of Hydrodynamics 2021年第4期33卷 657-672页

作者： Shan-hang Chi Chi Zhang Ti-ti Sui Zhu-bin Cao Jin-hai Zheng Jiang-shan Fan State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai UniversityNanjing210098China Key Laboratory of Ministry of Education for Coastal Disaster and Protection Hohai UniversityNanjing210098China College of Harbour Coastal and Offshore EngineeringHohai UniversityNanjing210098China Rizhao Port Group Co. Ltd.Rizhao276826China

Wave overtopping at a sea dike was observed using video images during a storm in July 2018 at Rizhao Coast,China.A shore-based video monitoring system was mounted to collect coastal images with a sample frequency of 1 Hz in the beginning 10 min of each hour during daylight.A method to extract the frequency,location,width and duration of individual overtopping events based on the shore-based video monitoring system was developed.A total of 6252 individual overtopping events were detected over a 360m long sea dike during the storm of 10 h in a safe and labor-saving way,enabling a detailed analysis of the temporal and spatial variation of wave *** temporal variation of overtopping duration,frequency and volume is basically in sync with the change of tidal level(R=0.87,0.82 and 0.76,respectively).The increase of wave height increases the overtopping frequency *** found a high correlation between the hourly observed data and the predicted results of two commonly used *** the previous field measurements of overtopping that were limited in a single location,significant spatial variation of overtopping in the alongshore direction is *** overtopping volume varies with a factor of 6 within the range of several wave *** is further revealed that the spatial variation of overtopping is highly correlated with the alongshore variation of surf zone width with a correlation coefficient of *** present study suggests the feasibility of shore-based video monitoring technique to capture the main features of wave overtopping at coastal dikes,providing new possibilities to monitor wave overtopping in the field and to improve prediction tools.

关键词： Wave overtopping coastal video monitoring field measurement temporal and spatial variations storm events