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ENJIN ZHAO received the B.S. and Ph.D. degrees from the College of Engineering, Ocean University of China, Qingdao, China, in 2012 and 2017, respectively. He is currently with the College of Marine Science and Technology, China University of Geosciences, Wuhan, China. His research interests include ocean engineering and marine technology.
As a coastal trading city in China, Shantou has complex terrain and changeable sea conditions in its coastal waters. In order to better protect the coastal engineering and social property along the coast, based on the numerical simulation method, this paper constructed a detailed hydrodynamic model of the Shantou sea area, and the measured tide elevation and tidal current were used to verify the accuracy of the model. Based on the simulation results, the tide elevation and current in the study area were analyzed, including the flood and ebb tides of astronomical spring tide, the flood and ebb tides of astronomical neap tide, the high tide, and the low tide. In order to find the main tidal constituent types in this sea, the influence of different tidal constituents on tide elevation and tidal current in the study area was analyzed. At the same time, the storm surge model of the study area was constructed, and the flow field under Typhoon “Mangkhut” in the study area was simulated by using the real recorded data. Typhoon wind fields with different recurrence periods and intensities were constructed to simulate the change in the flow field, the sea water level, and the disaster situation along the coast. The results showed that under normal sea conditions, the sea water flows from southwest to northeast at flood tide and the flow direction is opposite at ebb tide. The tidal range is large in the northwest and small in the southeast of the study area. The tides in the study area are mainly controlled by M2, S2, K1, and O1 tidal constituents, but N2, K2, P1, and Q1 tidal constituents have significant effects on the high water level. The water level caused by typhoons increases significantly along the coast of Shantou City. In the west area of the Rong River estuary, a typhoon with a lower central pressure than 910 hPa may induce a water increase of more than 2 m.
Yuezhao Tang; Yang Wang; Enjin Zhao; Jiaji Yi; Kecong Feng; HongBin Wang; Wanhu Wang. Study on Hydrodynamic Characteristics and Environmental Response in Shantou Offshore Area. Journal of Marine Science and Engineering 2021, 9, 912 .
AMA StyleYuezhao Tang, Yang Wang, Enjin Zhao, Jiaji Yi, Kecong Feng, HongBin Wang, Wanhu Wang. Study on Hydrodynamic Characteristics and Environmental Response in Shantou Offshore Area. Journal of Marine Science and Engineering. 2021; 9 (8):912.
Chicago/Turabian StyleYuezhao Tang; Yang Wang; Enjin Zhao; Jiaji Yi; Kecong Feng; HongBin Wang; Wanhu Wang. 2021. "Study on Hydrodynamic Characteristics and Environmental Response in Shantou Offshore Area." Journal of Marine Science and Engineering 9, no. 8: 912.
Many coastal countries are concerned with sustainable energy generation to meet their current and future energy needs. Tidal energy is an attractive resource as in-stream turbines can generate electricity even at moderate flow velocities. However, not all coastal areas are equally well-suited for tidal energy development. The survey of potential locations and their power densities is a crucial step in evaluating the potential cost-benefit of tidal energy. This research surveys the intensity and distribution of offshore tidal energy along whole coastline of China based on a high-resolution numerical simulation with a minimum mesh spacing of 80 m. The Finite Volume Community Ocean Model (FVCOM) has been used to carry out the numerical simulation work. Since FVCOM uses an unstructured mesh, it can accurately identify complex coastlines, such as those along islands, waterways, and estuaries. The simulation period for this numerical survey is 30 days. The accuracy of the simulation results is validated using 8-days in-situ measurements obtained at 17 coastal stations in the region of study. Research results indicate that the total mean tidal energy is 1.19 × 1014 J along the coastline of China. The tidal energy is mainly distributed in the south and southeast of the coastline of China. This study also identifies 45, 23 and 9 top sites, where the averaged tidal energy density is greater than 500, 1000, and 1500 W/m2, respectively, suitable for tidal energy extraction and utilization. Considering the long development cycle of tidal energy and global climate change, this study also investigates the impact of sea-level rise (SLR) on tidal energy distribution in the region of study using a 50-year (0.5 m) and 100-year (1.0 m) SLR scenarios. It is found that the total mean tidal energy increases by 3.0% and 6.5% for 50-year and 100-year SLR scenarios, respectively. It is believed that the findings drawn from this study could be instructive for future utilization of tidal energy along the coastline of China.
C.B. Jiang; Y.T. Kang; K. Qu; S. Kraatz; B. Deng; E.J. Zhao; Z.Y. Wu; J. Chen. High-resolution numerical survey of potential sites for tidal energy extraction along coastline of China under sea-level-rise condition. Ocean Engineering 2021, 236, 109492 .
AMA StyleC.B. Jiang, Y.T. Kang, K. Qu, S. Kraatz, B. Deng, E.J. Zhao, Z.Y. Wu, J. Chen. High-resolution numerical survey of potential sites for tidal energy extraction along coastline of China under sea-level-rise condition. Ocean Engineering. 2021; 236 ():109492.
Chicago/Turabian StyleC.B. Jiang; Y.T. Kang; K. Qu; S. Kraatz; B. Deng; E.J. Zhao; Z.Y. Wu; J. Chen. 2021. "High-resolution numerical survey of potential sites for tidal energy extraction along coastline of China under sea-level-rise condition." Ocean Engineering 236, no. : 109492.
Amphidrome refers to an oceanic point where the amplitude of one harmonic constituent of the tidal system is zero, and the phase of the harmonic constituent is undetermined. The concept of amphidrome can also be used in climatological studies because of the existence of annual amphidromes, points of zero amplitude and ill‐defined phase of annual cycle. This study investigated the global atmospheric geopotential height from the ERA‐Interim to identify annual amphidromes at different isobaric altitudes. Many well‐defined annual amphidromes were identified. These amphidromic points appear always as twins with different rotating directions with respect to phases. This phenomenon can be explained mathematically with the basic theory of spherical algebraic topology, suggesting amphidrome twins as a common feature for periodic variables in the atmosphere. Due to the spatial continuity of atmospheric parameters, amphidromes at different isobaric altitudes can be concatenated into amphidromic lines. Amphidromic lines have a three‐dimensional structure with both clockwise and anticlockwise vertical branches connected by one or two horizontal components. Particularly, some amphidromic lines in the atmosphere can be closed loops when they are connected by two horizontal components. The rotary phases around the amphidromic loops are similar to the magnetic induction lines around a closed electromagnetic coil.
Enjin Zhao; Lin Mu; Haoyu Jiang. Amphidromic Lines in the Atmosphere: An Example of Global Pressure Field Annual Harmonic. Earth and Space Science 2021, 8, 1 .
AMA StyleEnjin Zhao, Lin Mu, Haoyu Jiang. Amphidromic Lines in the Atmosphere: An Example of Global Pressure Field Annual Harmonic. Earth and Space Science. 2021; 8 (4):1.
Chicago/Turabian StyleEnjin Zhao; Lin Mu; Haoyu Jiang. 2021. "Amphidromic Lines in the Atmosphere: An Example of Global Pressure Field Annual Harmonic." Earth and Space Science 8, no. 4: 1.
Storm surge is a natural disaster, often causing economic damage and loss of human life in the coastal communities. In recent decades, with more people attracted to coastal areas, the potential economic losses resulted from storm surges are increasing. Therefore, it is important to make risk assessments to identify areas at risk and design risk reduction strategies. However, the quantitative risk assessment of storm surge for coastal cities in China is often difficult due to the lack of adequate data regarding the building footprint and vulnerability curves. This paper aims to provide a methodology for conducting the quantitative risk assessment of storm surge, estimating direct tangible damage, by using Geographical Information System (GIS) techniques and open data. The proposed methodology was applied to a coastal area with a high concentration of petroleum industries in the Daya Bay zone. At first, five individual typhoon scenarios with different return periods (1000, 100, 50, 20, and 10 years) were defined. Then, the Advanced Circulation model and the Simulating Waves Nearshore model were utilized to simulate storm surge. The model outputs were imported into GIS software, transformed into inundation area and inundation depth. Subsequently, the building footprint data were extracted by the use of GIS techniques, including spatial analysis and image analysis. The layer containing building footprints was superimposed on the inundation area layer to identify and quantify the exposed elements to storm surge hazard. Combining the exposed elements with their related depth–damage functions, the quantitative risk assessment translates the spatial extent and depth of storm surge into the estimation of economic losses. The quantitative risk assessment and zonation maps for sub-zones in the study area can help local decision-makers to prioritize the sub-zones that are more likely to be affected by storm surge, make risk mitigation strategies, and develop long-term urban plans.
Si Wang; Lin Mu; Mengnan Qi; Zekun Yu; Zhenfeng Yao; Enjin Zhao. Quantitative risk assessment of storm surge using GIS techniques and open data: A case study of Daya Bay Zone, China. Journal of Environmental Management 2021, 289, 112514 .
AMA StyleSi Wang, Lin Mu, Mengnan Qi, Zekun Yu, Zhenfeng Yao, Enjin Zhao. Quantitative risk assessment of storm surge using GIS techniques and open data: A case study of Daya Bay Zone, China. Journal of Environmental Management. 2021; 289 ():112514.
Chicago/Turabian StyleSi Wang; Lin Mu; Mengnan Qi; Zekun Yu; Zhenfeng Yao; Enjin Zhao. 2021. "Quantitative risk assessment of storm surge using GIS techniques and open data: A case study of Daya Bay Zone, China." Journal of Environmental Management 289, no. : 112514.
Submerged breakwater as the main structure of coastal engineering to protect coast is widely laid on the seabed because of its significant wave-dissipation performance. To reveal the interaction mechanism between waves and submerged breakwater, the hydrodynamic characteristics of a wave passing over different solid breakwaters were numerically and experimentally studied. Compared with the previous research, considering breakwater made up of porous media and the effects of extreme waves generated by hurricanes or tsunamis, this paper systematically investigates the effects of the semi-circular porous medium breakwater on the breaking solitary wave run-up based on a numerical model with the immersed boundary (IB) method. The computational capability of this model is verified firstly. Then, depending on the model, a series of cases are carried out to research the effects of different breakwaters on the run-up of solitary waves. The results show that the influence of porous breakwater on wave propagation is more significant than that of the solid breakwater. With the increase of the gravel particle median diameter, the maximum run-up height and the horizontal hydrodynamic force on the breakwater decrease, while the vertical hydrodynamic force on the breakwater increases. Increasing the size of the breakwater is beneficial to reducing the wave run-up height and the forces on the sloping beach. Compared with the single breakwater, the impact of the tandem breakwater on the wave propagation is more significant.
Enjin Zhao; Youkou Dong; Yuezhao Tang; Xiaoyu Xia. Performance of submerged semi-circular breakwater under solitary wave in consideration of porous media. Ocean Engineering 2021, 223, 108573 .
AMA StyleEnjin Zhao, Youkou Dong, Yuezhao Tang, Xiaoyu Xia. Performance of submerged semi-circular breakwater under solitary wave in consideration of porous media. Ocean Engineering. 2021; 223 ():108573.
Chicago/Turabian StyleEnjin Zhao; Youkou Dong; Yuezhao Tang; Xiaoyu Xia. 2021. "Performance of submerged semi-circular breakwater under solitary wave in consideration of porous media." Ocean Engineering 223, no. : 108573.
Submarine pipelines, as an important tool for oil and gas transportation, have been distributed in offshore oil and gas fields worldwide. Under extreme waves, a large number of submarine pipelines have been damaged in the past decades. In order to investigate the effect of extreme marine environments on the pipelines, the joint effect of solitary waves and background currents on the pipelines is numerically studied in this paper by using a numerical wave tank developed with a free surface tracking approach and the immersed boundary method. The sediment transport module including packed and suspended sediment is incorporated with the flow module. In order to ensure the calculation accuracy of this model, three verification cases related to the wave propagation profile, the hydrodynamic force on the cylinder and the scour hole profile are simulated and the numerical results match the experimental and analytical results well. Given the combined wave exerts on the different pipelines, the environmental variables consider the background current velocity and wave height, and the pipeline arrangement includes the different diameters and the suspended pipeline and tandem pipeline. It is noted that the hydrodynamic characteristics, the forces and the local scour around the pipeline are closely related to the background current and the diameter and layout of the pipeline. It is anticipated that the findings in this paper will enhance our understanding of the damage mechanism of submarine pipeline by waves and may also be useful in future design practices for pipelines.
Enjin Zhao; Youkou Dong; Yuezhao Tang; Junkai Sun. Numerical investigation of hydrodynamic characteristics and local scour mechanism around submarine pipelines under joint effect of solitary waves and currents. Ocean Engineering 2021, 222, 108553 .
AMA StyleEnjin Zhao, Youkou Dong, Yuezhao Tang, Junkai Sun. Numerical investigation of hydrodynamic characteristics and local scour mechanism around submarine pipelines under joint effect of solitary waves and currents. Ocean Engineering. 2021; 222 ():108553.
Chicago/Turabian StyleEnjin Zhao; Youkou Dong; Yuezhao Tang; Junkai Sun. 2021. "Numerical investigation of hydrodynamic characteristics and local scour mechanism around submarine pipelines under joint effect of solitary waves and currents." Ocean Engineering 222, no. : 108553.
Tsunamis induced by the landslide will divide into a traveling wave component propagating along the coastline and an offshore wave component propagating perpendicular to the coastline. The offshore tsunami wave has the non-negligible energy and destruction in enclosed basins as fjords, reservoirs, and lakes, which are worth studying. The initial submergence condition, the falling height and sliding angle of slider, are important reference indexes of damage degree of landslide and may also matter at that of the landslide-induced tsunami. Depending on the fully coupled model, the effects of them on the production and propagation of the tsunami were considered in the study. Since the slider used was semi-elliptic, the effect of the ratio of the long axis to the short axis was also analyzed. According to the computational fluid dynamics theory, a numerical wave tank was developed by the immersed boundary (IB) method; besides, the general moving-object module of slide mass was also embedded to the numerical tanker. The results indicate that the effects of the squeezing and pushing of the slider on water produce a naturally attenuated wave at the front of the wave train, and the attenuation becomes more serious with the increase in the initial submersion range of the slider. The effects of the vertical movement of the slider cause the increase in the amplitude of the back of the wave train. As the falling height increases, the large wave height increases when the slider is initially submerged and decreases when it is not initially submerged, except for the accidental elevation of that at smaller falling heights. The results also indicate that the hazard of the subaerial landslide-induced tsunami is greater under a small or large falling angle, and that of the partial subaerial and submarine landslide-induced tsunami is greater under a small falling angle. With the increase in the ratio of the long axis to the short axis, the total induced wave energy decreases and the shape of the wave train proportionally reduces, while the wave propagation mode does not change.
Junkai Sun; Yang Wang; Cheng Huang; Wanhu Wang; Hongbing Wang; Enjin Zhao. Numerical Investigation on Generation and Propagation Characteristics of Offshore Tsunami Wave under Landslide. Applied Sciences 2020, 10, 5579 .
AMA StyleJunkai Sun, Yang Wang, Cheng Huang, Wanhu Wang, Hongbing Wang, Enjin Zhao. Numerical Investigation on Generation and Propagation Characteristics of Offshore Tsunami Wave under Landslide. Applied Sciences. 2020; 10 (16):5579.
Chicago/Turabian StyleJunkai Sun; Yang Wang; Cheng Huang; Wanhu Wang; Hongbing Wang; Enjin Zhao. 2020. "Numerical Investigation on Generation and Propagation Characteristics of Offshore Tsunami Wave under Landslide." Applied Sciences 10, no. 16: 5579.
Due to the strong interaction between the bridges and the extreme waves generated by hurricanes and tsunamis, many coastal bridges were damaged in the past few decades. In this study, in order to investigate the effect of the extreme wave on a bridge, tsunami-like wave generated based on record in the Iwate station during 2011 Japan tsunami event instead of solitary wave is employed to impinge on the bridge with or without air vent. According to the Computational Fluid Dynamics (CFD) theory with a Volume of Fluid (VOF) interface tracking approach, a Numerical Wave Tank (NWT) is developed, in which the Immersed Boundary (IB) method is referred to simulate fluid and structure interaction. The model is calibrated with the experiment. In this numerical tank, the effects of tsunami-like waves with different prominent conditions including wave height and submersion depth on the bridges are studied. Besides, the efficiency of air vent in reducing the hydrodynamic load is also discussed. The results indicate that when the tsunami-like wave overtops the bridges, a noticeable overtopping, where the flow injects into the water fiercely and the whole flow field is very chaotic, is observed. The vertical forces on the bridges are larger than the horizontal forces, leading to many decks to collapse between two piers with small lateral displacement after the hurricanes and tsunamis. After the tsunami-like wave passes over the bridge, the oscillation of the residual wave causes the load oscillation of the bridge. The position of the bridge relative to the initial sea level has a serious impact on the forces on the bridge when the tsunami-like wave passes through it. With the increase of the wave height, the interaction intensity between the tsunami-like wave and the bridge is enhanced and the forces on the bridge also increase, but the effect duration reduces. After the air vent is installed, air vent can reduce the forces on the bridge and improve the efficiency of the bridge protection.
Enjin Zhao; Junkai Sun; Yuezhao Tang; Lin Mu; Haoyu Jiang. Numerical investigation of tsunami wave impacts on different coastal bridge decks using immersed boundary method. Ocean Engineering 2020, 201, 107132 .
AMA StyleEnjin Zhao, Junkai Sun, Yuezhao Tang, Lin Mu, Haoyu Jiang. Numerical investigation of tsunami wave impacts on different coastal bridge decks using immersed boundary method. Ocean Engineering. 2020; 201 ():107132.
Chicago/Turabian StyleEnjin Zhao; Junkai Sun; Yuezhao Tang; Lin Mu; Haoyu Jiang. 2020. "Numerical investigation of tsunami wave impacts on different coastal bridge decks using immersed boundary method." Ocean Engineering 201, no. : 107132.
Lin Mu; Enjin Zhao; Yuewei Wang; Albert Y. Zomaya. Buoy Sensor Cyberattack Detection in Offshore Petroleum Cyber-Physical Systems. IEEE Transactions on Services Computing 2020, 13, 653 -662.
AMA StyleLin Mu, Enjin Zhao, Yuewei Wang, Albert Y. Zomaya. Buoy Sensor Cyberattack Detection in Offshore Petroleum Cyber-Physical Systems. IEEE Transactions on Services Computing. 2020; 13 (4):653-662.
Chicago/Turabian StyleLin Mu; Enjin Zhao; Yuewei Wang; Albert Y. Zomaya. 2020. "Buoy Sensor Cyberattack Detection in Offshore Petroleum Cyber-Physical Systems." IEEE Transactions on Services Computing 13, no. 4: 653-662.
Submarine Pipeline End Manifold (PLEM) is the converge end or termination of submarine pipelines, which is used to provide additional support for equipment in the submarine production system on the seafloor. However, PLEM is vulnerable to extreme waves (i.e., tsunami waves). In this study, a two-phase flow model is developed with the finite volume method for simulating the tsunami-like wave impinging on the PLEM. Depending on the real-world tsunami wave recorded in 2011 tsunami event, a tsunami-like wave is generated numerically depending on N-waves theory. In order to ensure the accuracy of the calculation, this model is verified against some theoretical and experimental studies firstly. Then, the hydrodynamic characteristics and forces on the PLEMs under the different tsunami-like waves are investigated systematically. Due to the flow causes strong disturbance to different parts of the PLEMs, the Fast Fourier Transform (FFT) method is adopted to analyze the irregular hydrodynamic force signals for better to understand the characteristics of forces in the frequency domain. In the simulations, different environmental and PLEM structural variables are considered, such as wave height, pipe distance, and PLEM bottom seat length. The hydrodynamic characteristics under different tsunami-like waves passing the various submarine PLEMs are discussed, which indicates that the vortex field evolutions and hydrodynamic forces under different waves on the PLEM are significantly different.
Enjin Zhao; Yuezhao Tang; Jie Shao; Lin Mu. Numerical Analysis of Hydrodynamics Around Submarine Pipeline End Manifold (PLEM) Under Tsunami-Like Wave. IEEE Access 2019, 7, 178903 -178917.
AMA StyleEnjin Zhao, Yuezhao Tang, Jie Shao, Lin Mu. Numerical Analysis of Hydrodynamics Around Submarine Pipeline End Manifold (PLEM) Under Tsunami-Like Wave. IEEE Access. 2019; 7 (99):178903-178917.
Chicago/Turabian StyleEnjin Zhao; Yuezhao Tang; Jie Shao; Lin Mu. 2019. "Numerical Analysis of Hydrodynamics Around Submarine Pipeline End Manifold (PLEM) Under Tsunami-Like Wave." IEEE Access 7, no. 99: 178903-178917.
In recent tsunami events like those happened in the Indian Ocean in 2004 and 2018 and in Japan in 2011, many ocean and coastal infrastructures have been damaged tremendously, revealing the need of the work to study the hydrodynamic interaction between real-world tsunami waves and offshore structures. Besides, the destructive energy of tsunami wave on the offshore structures should also be assessed. However, to study the impact of tsunami waves on offshore structures, solitary waves are used generally instead of real-world tsunami waves despite the vast differences in hydrodynamic characteristics. Using Computational Fluid Dynamics (CFD) approach, this paper investigates the hydrodynamic characteristics of the floating cylinders moored by chains, under the real-world tsunami-like waves (2011 Japan Tohoku tsunami). Comparisons of hydrodynamic characteristics between real-world tsunami-like wave and solitary wave propagating over the moored cylinders are analyzed and discussed, indicating that the flow fields, the tension forces of mooring chains, the impinging forces and the movement trajectories of the cylinder caused by the two types of waves are greatly different from each other. Moreover, the influences of single cylinder diameter and tandem cylinder spacing on the interaction between real-world tsunami-like waves and cylinders are considered through a series of simulation tests, while meaningful conclusions are drawn.
Enjin Zhao; Junkai Sun; Haoyu Jiang; Lin Mu. Numerical Study on the Hydrodynamic Characteristics and Responses of Moored Floating Marine Cylinders Under Real-World Tsunami-Like Waves. IEEE Access 2019, 7, 122435 -122458.
AMA StyleEnjin Zhao, Junkai Sun, Haoyu Jiang, Lin Mu. Numerical Study on the Hydrodynamic Characteristics and Responses of Moored Floating Marine Cylinders Under Real-World Tsunami-Like Waves. IEEE Access. 2019; 7 (99):122435-122458.
Chicago/Turabian StyleEnjin Zhao; Junkai Sun; Haoyu Jiang; Lin Mu. 2019. "Numerical Study on the Hydrodynamic Characteristics and Responses of Moored Floating Marine Cylinders Under Real-World Tsunami-Like Waves." IEEE Access 7, no. 99: 122435-122458.
Submarine piggyback pipeline is an important tool for oil and gas transport, especially, in the marginal oil field. When the scour happens in the seabed, the pipeline slides easily, which may cause the pipeline failure. The dynamic slope angle is one of the most important characteristics of the scour. In this work, the dynamic slope angles of the sandy seabed under piggyback pipelines in steady flow are investigated experimentally and numerically in detail. The physical experiments are conducted in an annular flume and the numerical simulations are carried out using a two-phase flow model which is resolved by the finite volume method (FVM). In the numerical model, the free surface is tracked by the volume of fluid (VOF), and both bed and suspended loads are considered in the scour module. Depending on the comparison and convergence analysis, the numerical results are in good agreement with the experimental results. The results indicate that the dynamic slope angle is significantly affected by the incoming flow velocity, gap-ratio, spacing-ratio and pipe diameter. With the reduction of gap-ratio and space-ratio, the upstream dynamic slope angle α increases slightly, but the downstream dynamic slope angle β decreases. With the increase of the grain Reynolds number, the angle α increases slightly, but the angle β decreases severely. The conclusions drawn from this paper could provide the reference for the design of submarine piggyback pipeline.
Enjin Zhao; Lin Mu; Hao Qin; Haoyu Jiang. Study on dynamic slope angle of sandy seabed around the submarine piggyback pipeline in steady flow. Journal of Marine Engineering & Technology 2019, 1 -13.
AMA StyleEnjin Zhao, Lin Mu, Hao Qin, Haoyu Jiang. Study on dynamic slope angle of sandy seabed around the submarine piggyback pipeline in steady flow. Journal of Marine Engineering & Technology. 2019; ():1-13.
Chicago/Turabian StyleEnjin Zhao; Lin Mu; Hao Qin; Haoyu Jiang. 2019. "Study on dynamic slope angle of sandy seabed around the submarine piggyback pipeline in steady flow." Journal of Marine Engineering & Technology , no. : 1-13.
In recent tsunami events, as those happened in Japan in 2011 and in Indian Ocean in 2018, many ocean and coastal structures have been damaged tremendously. Seawall is one of the most important coastal infrastructures to withstand the tsunami and reduce the harm of the tsunami. The investigation of the interaction between the seawall and tsunami wave is a significant aspect to reveal the influence mechanism of the tsunami and decrease the tsunami risk. With this scope, the effect of tsunami-like wave on the seawall and sandy bed is analyzed by the coupling model of fluid and sediment modules. The free surface of the fluid module is captured using VOF technology. The sediment transport module contains the calculation methods of sediment drift, precipitation and suspension. In order to guarantee the accuracy of the calculation, this model is verified through the comparison between the numerical and experimental data. The tsunami-like wave generated according to the record in the Iwate station in 2011 Japan tsunami event is used to impinge the seawall. After the wave overflows the seawall, the sandy bed is scoured. Based on the force on the seawall and scour hole profile, the damage energy of the tsunami-like wave is assessed. Besides, the influence of solitary wave on the seawall and sandy bed is also studied for comparison. It is found that the coastal scour caused by the tsunami-like wave is more serious than solitary wave. With the increase of wave height, the forces on the seawall and the scour depth increase. When the seawall is widened, the effect of the seawall on the wave reflection is enhanced, however, much water still can pass over the seawall. The outcome of this analysis can provide a reference for the construction of the seawall and improve the understanding of the interaction between the tsunami wave and the marine infrastructures.
Enjin Zhao; Ke Qu; Lin Mu. Numerical study of morphological response of the sandy bed after tsunami-like wave overtopping an impermeable seawall. Ocean Engineering 2019, 186, 106076 .
AMA StyleEnjin Zhao, Ke Qu, Lin Mu. Numerical study of morphological response of the sandy bed after tsunami-like wave overtopping an impermeable seawall. Ocean Engineering. 2019; 186 ():106076.
Chicago/Turabian StyleEnjin Zhao; Ke Qu; Lin Mu. 2019. "Numerical study of morphological response of the sandy bed after tsunami-like wave overtopping an impermeable seawall." Ocean Engineering 186, no. : 106076.
Submarine pipelines have been extensively used for marine oil and gas extraction due to their high efficiency, safety, and low price. However, submarine pipelines are vulnerable to extreme waves (i.e., tsunami waves). Previous research has often used solitary waves as a basis for studying the impacts of tsunami waves on submarine pipelines, although the hydrodynamic characteristics and wave properties drastically differ from those of real-world tsunami waves. This paper numerically investigates the hydrodynamic characteristics of tsunami waves interacting with submarine pipelines, but instead uses an improved wave model to generate a tsunami-like wave that more closely resembles those encountered in the real-world. The tsunami-like wave generated based on a real-world tsunami wave profile recorded during a 2011 tsunami in Japan has been applied. Given the same wave height, simulation results show that peak hydrodynamic forces of the tsunami-like wave are greater than those of the solitary wave. Meanwhile, the duration of the acting force under the tsunami-like wave is much longer than that of the solitary wave. These findings underline the basic reasons for the destructive power of tsunamis. It is also noted that the hydrodynamic forces of the pipeline under the tsunami-like wave increase with wave height, but will decrease as water depth increases. In addition to the single pipeline, the complicated hydrodynamic characteristics of pipelines in tandem arrangement have been also numerically studied. It is believed that the findings drawn from this paper can enhance our understanding of the induced forces on submarine pipelines under extreme tsunami waves.
Enjin Zhao; Ke Qu; Lin Mu; Simon Kraatz; Bing Shi. Numerical Study on the Hydrodynamic Characteristics of Submarine Pipelines under the Impact of Real-World Tsunami-Like Waves. Water 2019, 11, 221 .
AMA StyleEnjin Zhao, Ke Qu, Lin Mu, Simon Kraatz, Bing Shi. Numerical Study on the Hydrodynamic Characteristics of Submarine Pipelines under the Impact of Real-World Tsunami-Like Waves. Water. 2019; 11 (2):221.
Chicago/Turabian StyleEnjin Zhao; Ke Qu; Lin Mu; Simon Kraatz; Bing Shi. 2019. "Numerical Study on the Hydrodynamic Characteristics of Submarine Pipelines under the Impact of Real-World Tsunami-Like Waves." Water 11, no. 2: 221.
The interaction between coastal ocean flows and the submarine pipeline involved with distinct physical phenomena occurring at a vast range of spatial and temporal scales has always been an important research subject. In this article, the hydrodynamic forces on the submarine pipeline and the characteristics of tidal flows around the pipeline are studied depending on a high-fidelity multi-physics modeling system (SIFOM–FVCOM), which is an integration of the Solver for Incompressible Flow on the Overset Meshes (SIFOM) and the Finite Volume Coastal Ocean Model (FVCOM). The interactions between coastal ocean flows and the submarine pipeline are numerically simulated in a channel flume, the results of which show that the hydrodynamic forces on the pipeline increase with the increase of tidal amplitude and the decrease of water depth. Additionally, when scour happens under the pipeline, the numerical simulation of the suspended pipeline is also carried out, showing that the maximum horizontal hydrodynamic forces on the pipeline reduce and the vertical hydrodynamic forces grow with the increase of the scour depth. According to the results of the simulations in this study, an empirical formula for estimating the hydrodynamic forces on the submarine pipeline caused by coastal ocean flows is given, which might be useful in engineering problems. The results of the study also reveal the basic features of flow structures around the submarine pipeline and its hydrodynamic forces caused by tidal flows, which contributes to the design of submarine pipelines.
Enjin Zhao; Lin Mu; Bing Shi. Numerical Study of the Influence of Tidal Current on Submarine Pipeline Based on the SIFOM–FVCOM Coupling Model. Water 2018, 10, 1814 .
AMA StyleEnjin Zhao, Lin Mu, Bing Shi. Numerical Study of the Influence of Tidal Current on Submarine Pipeline Based on the SIFOM–FVCOM Coupling Model. Water. 2018; 10 (12):1814.
Chicago/Turabian StyleEnjin Zhao; Lin Mu; Bing Shi. 2018. "Numerical Study of the Influence of Tidal Current on Submarine Pipeline Based on the SIFOM–FVCOM Coupling Model." Water 10, no. 12: 1814.
As a new type of submarine pipeline, the piggyback pipeline has been gradually adopted in engineering practice to enhance the performance and safety of submarine pipelines. However, limited simulation work and few experimental studies have been published on the scour around the piggyback pipeline under steady current. This study numerically and experimentally investigates the local scour of the piggyback pipe under steady current. The influence of prominent factors such as pipe diameter, inflow Reynolds number, and gap between the main and small pipes, on the maximum scour depth have been examined and discussed in detail. Furthermore, one formula to predict the maximum scour depth under the piggyback pipeline has been derived based on the theoretical analysis of scour equilibrium. The feasibility of the proposed formula has been effectively calibrated by both experimental data and numerical results. The findings drawn from this study are instructive in the future design and application of the piggyback pipeline.
Enjin Zhao; Bing Shi; Ke Qu; Wenbin Dong; Jing Zhang. Experimental and Numerical Investigation of Local Scour Around Submarine Piggyback Pipeline Under Steady Current. Journal of Ocean University of China 2018, 17, 244 -256.
AMA StyleEnjin Zhao, Bing Shi, Ke Qu, Wenbin Dong, Jing Zhang. Experimental and Numerical Investigation of Local Scour Around Submarine Piggyback Pipeline Under Steady Current. Journal of Ocean University of China. 2018; 17 (2):244-256.
Chicago/Turabian StyleEnjin Zhao; Bing Shi; Ke Qu; Wenbin Dong; Jing Zhang. 2018. "Experimental and Numerical Investigation of Local Scour Around Submarine Piggyback Pipeline Under Steady Current." Journal of Ocean University of China 17, no. 2: 244-256.
In view of the severity of oceanic pollution, based on the finite volume coastal ocean model (FVCOM), a Lagrangian particle-tracking model was used to numerically investigate the coastal pollution transport and water exchange capability in Tangdao Bay, in China. The severe pollution in the bay was numerically simulated by releasing and tracking particles inside it. The simulation results demonstrate that the water exchange capability in the bay is very low. Once the bay has suffered pollution, a long period will be required before the environment can purify itself. In order to eliminate or at least reduce the pollution level, environmental improvement measures have been proposed to enhance the seawater exchange capability and speed up the water purification inside the bay. The study findings presented in this paper are believed to be instructive and useful for future environmental policy makers and it is also anticipated that the numerical model in this paper can serve as an effective technological tool to study many emerging coastal environment problems.
En-Jin Zhao; Lin Mu; Ke Qu; Bing Shi; Xing-Yue Ren; Chang-Bo Jiang. Numerical investigation of pollution transport and environmental improvement measures in a tidal bay based on a Lagrangian particle-tracking model. Water Science and Engineering 2018, 11, 23 -38.
AMA StyleEn-Jin Zhao, Lin Mu, Ke Qu, Bing Shi, Xing-Yue Ren, Chang-Bo Jiang. Numerical investigation of pollution transport and environmental improvement measures in a tidal bay based on a Lagrangian particle-tracking model. Water Science and Engineering. 2018; 11 (1):23-38.
Chicago/Turabian StyleEn-Jin Zhao; Lin Mu; Ke Qu; Bing Shi; Xing-Yue Ren; Chang-Bo Jiang. 2018. "Numerical investigation of pollution transport and environmental improvement measures in a tidal bay based on a Lagrangian particle-tracking model." Water Science and Engineering 11, no. 1: 23-38.
K. Qu; X.Y. Ren; S. Kraatz; E.J. Zhao. Numerical analysis of tsunami-like wave impact on horizontal cylinders. Ocean Engineering 2017, 145, 316 -333.
AMA StyleK. Qu, X.Y. Ren, S. Kraatz, E.J. Zhao. Numerical analysis of tsunami-like wave impact on horizontal cylinders. Ocean Engineering. 2017; 145 ():316-333.
Chicago/Turabian StyleK. Qu; X.Y. Ren; S. Kraatz; E.J. Zhao. 2017. "Numerical analysis of tsunami-like wave impact on horizontal cylinders." Ocean Engineering 145, no. : 316-333.
This paper presents the results from laboratory experiments and theoretical analysis to investigate the development of scour around submarine pipeline under steady current conditions. Experiments show that the scour process takes place in two stages: the initial rapid scour and the subsequent gradual scour development stage. An empirical formula for calculating the equilibrium scour depth (the maximum scour depth) is developed by using the regression method. This formula together with the maximum entropy theory can be applied to establish a formula to predict the scour process for given water depth, diameter of pipeline and flow velocity. Good agreement between the predicted and measured scour depth is obtained.
Jing Zhang; Bing Shi; Yakun Guo; Weilin Xu; Kejun Yang; Enjin Zhao. Scour development around submarine pipelines due to current based on the maximum entropy theory. Journal of Ocean University of China 2016, 15, 841 -846.
AMA StyleJing Zhang, Bing Shi, Yakun Guo, Weilin Xu, Kejun Yang, Enjin Zhao. Scour development around submarine pipelines due to current based on the maximum entropy theory. Journal of Ocean University of China. 2016; 15 (5):841-846.
Chicago/Turabian StyleJing Zhang; Bing Shi; Yakun Guo; Weilin Xu; Kejun Yang; Enjin Zhao. 2016. "Scour development around submarine pipelines due to current based on the maximum entropy theory." Journal of Ocean University of China 15, no. 5: 841-846.
Two-dimensional incompressible fluid flows over a periodically deforming circular cylinder are simulated with lattice Boltzmann method for Reynolds number 200. The periodic deformation is controlled by the ratios of deforming amplitude relative to the cylindrical radius and deforming frequency relative to natural vortex shedding frequency. The flow features are mainly decided by the periodic deformation. So three deforming amplitude ratios (0.05, 0.075, 0.1) are considered and deforming frequency ratios range from 0.75 to 2.0. The vortex structures are divided into three categories and two type transitional structures are observed. The correlation between vortex shedding patterns and periodic deformation is analyzed. In addition, the impact of periodic deformation to drag coefficient is studied. Numerical results show that special deformation can reduce the drag.
Haicheng Zheng; Bing Shi; Qian Yu; Enjin Zhao. Numerical study of flow over periodically deforming circular cylinder. Computers & Fluids 2016, 136, 348 -353.
AMA StyleHaicheng Zheng, Bing Shi, Qian Yu, Enjin Zhao. Numerical study of flow over periodically deforming circular cylinder. Computers & Fluids. 2016; 136 ():348-353.
Chicago/Turabian StyleHaicheng Zheng; Bing Shi; Qian Yu; Enjin Zhao. 2016. "Numerical study of flow over periodically deforming circular cylinder." Computers & Fluids 136, no. : 348-353.