scholarly journals Influence of Erodible Beds on Shallow Water Hydrodynamics during Flood Events

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3340
Author(s):  
David Santillán ◽  
Luis Cueto-Felgueroso ◽  
Alvaro Sordo-Ward ◽  
Luis Garrote
Keyword(s):  
Numerical Simulations ◽  
Shallow Water ◽  
Water Flow ◽  
Water Depth ◽  
Velocity Fields ◽  
Economic Losses ◽  
Flood Events ◽  
Erosion And Deposition ◽  
The Impact ◽  
Erodible Beds

Flooding has become the most common environmental hazard, causing casualties and severe economic losses. Mathematical models are a useful tool for flood control, and current computational resources let us simulate flood events with two-dimensional (2D) approaches. An open question is whether bed erosion must be accounted for when it comes to simulating flood events. In this paper we answer this question through numerical simulations using the 2D depth-averaged shallow-water equations. We analyze the effect of mobile beds on the flow patterns during flood events. We focus on channel confluences where water flow and sediment mobilization have a marked 2D behavior. We validate our numerical simulations with laboratory experiments of erodible beds with satisfactory results. Moreover, our sensitivity analysis indicates that the bed roughness model has a great influence on the simulated erosion and deposition patterns. We simulate the sediment transport and its influence on the water flow in a real river confluence during flood events. Our simulations show that the erosion and deposition processes play an important role on the water depth and flow velocity patterns. Accounting for the mobile bed leads to smoother water depth and velocity fields, as abrupt fields for the non-erodible model emerge from the irregular bed topography. Our study highlights the importance of accounting for erosion in the simulation of flood events, and the impact on the water depth and velocity fields.

Impact of Elastic Body on the Deep and Shallow Water

2013 ◽  
Author(s):  
Alexander A. Korobkin ◽  
Tatyana I. Khabakhpasheva
Keyword(s):  
Shallow Water ◽  
Elastic Body ◽  
Water Depth ◽  
The Body ◽  
Complex Structures ◽  
Water Impact ◽  
One Dimensional ◽  
Mode Method ◽  
Bending Stresses ◽  
The Impact

Two-dimensional unsteady problem of elastic body impact on liquid free surface is considered. The water is either of infinite depth or shallow. We are concerned with the effect of the water depth on the bending stresses in the structure caused by the fluid-structure interaction. The Wagner model is used for infinite water depth. In the case of shallow water impact, the hydrodynamic problem is one-dimensional but nonlinear. Both problems for deep and shallow waters are solved numerically by the normal mode method. Two shapes of the body, cylindrical shell and elastic wedge, are considered. The impact conditions and the structural characteristic are identical. The bending stresses in the structure are investigated. It is shown that the bending stresses for impact on shallow water are greater than those for the infinite water depth. The developed methods and approaches can be combined with FFM to include complex structures.

scholarly journals Simulation of storm surge inundation under different typhoon intensity scenarios: case study of Pingyang County, China

2020 ◽  
Vol 20 (10) ◽  
pp. 2777-2790
Author(s):  
Xianwu Shi ◽  
Pubing Yu ◽  
Zhixing Guo ◽  
Zhilin Sun ◽  
Fuyuan Chen ◽  
...  
Keyword(s):  
Storm Surge ◽  
Water Depth ◽  
Storm Surges ◽  
Economic Losses ◽  
Astronomical Tide ◽  
Evacuation Plans ◽  
Typhoon Intensity ◽  
Typhoon Tracks ◽  
The Impact

Abstract. China is one of the countries that is most seriously affected by storm surges. In recent years, storm surges in coastal areas of China have caused huge economic losses and a large number of human casualties. Knowledge of the inundation range and water depth of storm surges under different typhoon intensities could assist predisaster risk assessment and making evacuation plans, as well as provide decision support for responding to storm surges. Taking Pingyang County in Zhejiang Province as a case study area, parameters including typhoon tracks, radius of maximum wind speed, astronomical tide, and upstream flood runoff were determined for different typhoon intensities. Numerical simulations were conducted using these parameters to investigate the inundation range and water depth distribution of storm surges in Pingyang County considering the impact of seawall collapse under five different intensity scenarios (corresponding to minimum central pressure values equal to 915, 925, 935, 945, and 965 hPa). The inundated area ranged from 103.51 to 233.16 km2 for the most intense typhoon. The proposed method could be easily adopted in various coastal counties and serves as an effective tool for decision-making in storm surge disaster risk reduction practices.

Wave Spreading and Wave Drift Loads for a Standard LNG Carrier in Shallow Water

2010 ◽  
Author(s):  
Emmanuel Sergent ◽  
Mamoun Naciri
Keyword(s):  
Natural Gas ◽  
Shallow Water ◽  
Natural Frequency ◽  
Water Depth ◽  
Storage Capacity ◽  
Mooring System ◽  
Spectral Densities ◽  
Floating Structures ◽  
Wave Drift ◽  
The Impact

The need for LNG export and import terminals is anticipated to grow as natural gas progressively accounts for a larger fraction of worldwide consumed energy. These terminals are preferably located nearshore i.e. in relatively shallow water. Design of floating structures is most of the time performed assuming long-crested waves. In shallow water, diffraction of waves by a variable bathymetry can result in wave spreading i.e. in short crested seas. The effect of short crested seas on the wave drift load spectral densities for a 135,000m3 storage capacity LNG Carrier in 15m water depth is investigated. It is shown that the impact of wave spreading on drift loads depends on the natural frequency of the moored vessel and thus on the stiffness of the mooring system under consideration. Although response calculations are not performed herein for reasons to be discussed, it is conceivable that wave spreading could adversely affect loading/offloading terminal availability for stiff moorings.

Shallow Water STL Mooring and Riser System

2009 ◽  
Author(s):  
Qinzheng Yang ◽  
Muthu Chezhian ◽  
Geir Olav Hovde
Keyword(s):  
Shallow Water ◽  
Wave Height ◽  
Model Test ◽  
Water Depth ◽  
Significant Wave Height ◽  
Mooring Line ◽  
Test Results ◽  
Sea State ◽  
Significant Wave ◽  
The Impact

A shallow water disconnectable STL turret mooring and riser system has been developed for water depth between 30 and 50 m. This technology is based on APL’s disconnectable STL (Submerged Turret Loading) and STP (Submerged Turret Production) technologies which had been widely applied for water depth between 70 m to 2600 m for FPSOs and LNG offshore terminals. The advantage of disconnectable system is that the mooring and riser system can be designed to a preferred sea state. When the sea state is higher than design sea state (like hurricane), the vessel can be disconnected and sail away. The shallow water STL system consists of STL buoy, mooring lines, riser system and landing pad. The interface with vessel is the same as traditional STL system. The mooring and riser system are connected to the vessel through STL buoy and can be pulled into vessel by using ship winch. Unlike traditional STP and STL buoys, the shallow STL buoy has a net weight and will stay on the landing pad when disconnected from vessel. The landing pad is designed to support the impact load from STL buoy and supply enough friction for the STL buoy to stay in position during 100-year storm. The mooring system design has taken the advantage of directionality of weather when close to the shore by using different mooring line length in different directions. Further an innovative Hold-Back-Wave riser configuration has been developed for shallow water system. The riser configuration has a larger flexibility compared to traditional wave configuration and has proved to be feasible for significant wave height at least 7 m when connected to the vessel and 10+ m when disconnected from the vessel. Model test for the disconnectable shallow water turret mooring and riser system had been performed in MARINTEK, Trondheim with a LNG re-gasification vessel model at 30 m water depth. For connected system, significant wave height Hs = 6 m and 8 m has been tested. The mooring and riser system perform well, as predicted. For disconnected system (when the buoy sitting on the landing pad), significant wave height Hs = 10 m has been tested. The STL buoy is sitting on the landing pad without significant movement and the riser system performs well. SIMO program has been used to calibrate the model test results with numerical simulations. By adjusting surge, sway, yaw damping and 2nd order wave drift force, the calibrated SIMO model agrees well with model test results and can be used for similar development.

Acceleration statistics of tracer particles in filtered turbulent fields

2018 ◽  
Vol 847 ◽  
Author(s):  
Cristian C. Lalescu ◽  
Michael Wilczek
Keyword(s):  
Particle Size ◽  
Numerical Simulations ◽  
Spatial Scales ◽  
Velocity Fields ◽  
Direct Numerical Simulations ◽  
Small Scale ◽  
Turbulent Fluctuations ◽  
Tracer Particles ◽  
Neutrally Buoyant ◽  
The Impact

We present results from direct numerical simulations of tracer particles advected in filtered velocity fields to quantify the impact of the scales of turbulence on Lagrangian acceleration statistics. Systematically removing spatial scales reduces the frequency of extreme acceleration events, consistent with the notion that they are rooted in the small-scale structure of turbulence. We also find that acceleration variance and flatness as a function of filter scale closely resemble experimental results of neutrally buoyant, finite-sized particles, corroborating the picture that particle size determines the scale on which turbulent fluctuations are sampled.

scholarly journals Simulation of storm surge inundation under different typhoon intensity scenarios: Case study of Pingyang County, China

2020 ◽  
Author(s):  
Xianwu Shi ◽  
Pubing Yu ◽  
Zhixing Guo ◽  
Fuyuan Chen ◽  
Xiuguang Wu ◽  
...  
Keyword(s):  
Storm Surge ◽  
Water Depth ◽  
Storm Surges ◽  
Economic Losses ◽  
Astronomical Tide ◽  
Evacuation Plans ◽  
Northern Areas ◽  
Typhoon Intensity ◽  
Typhoon Tracks ◽  
The Impact

Abstract. China is one of the countries that are most seriously affected by storm surges. In recent years, storm surges in coastal areas of China have caused huge economic losses and a large number of human casualties. Knowledge of the inundation range and water depth of storm surges under different typhoon intensities could assist pre-disaster risk assessment and making evacuation plans, as well as provide decision support for responding to storm surges. Based on historical typhoon-induced storm surges in the study area of Pingyang County in Zhejiang Province, China, key parameters including typhoon tracks, radius of maximum wind speed, astronomical tide, and upstream flood runoff were determined for different typhoon intensities. Numerical simulations were conducted using these parameters to investigate the inundation range and water depth distribution of storm surges in Pingyang County under five different intensity scenarios (915, 925, 935, 945, and 965 hPa) with consideration of the impact of seawall collapse. The simulation results show that the range of storm surge inundation expands with increasing typhoon intensity. The scenario with the most intense typhoon (915 hPa) had the most adverse track, with an associated area of inundation of 233 km2 that included most areas of the town of Aojiang, eastern areas of Wanquan, northern areas of Songbu, as well as parts of Kunyang and Shuitou.

THE MAIN DIRECTIONS OF ECONOMIC SUPPORT OF THE REGIONAL SECURITY SYSTEM OF THE POPULATION

2020 ◽  
Vol 1 (11) ◽  
pp. 133-140
Author(s):  
E. V. DMITRIEVA ◽  
Keyword(s):  
Crisis Management ◽  
Security System ◽  
Regional Security ◽  
Economic Losses ◽  
Economic Damage ◽  
Economic Activities ◽  
The Sustainable Development ◽  
Economic Support ◽  
The Impact ◽  
Crisis Situations

The article considers topical issues of economic support for the development of the regional security system of the population against various risks. The dependence of the impact of the scale of crisis situations on economic activities in the constituent entities of the Russian Federation, which become a serious barrier to the sustainable development of the regions of the country, was investigated. The increasing importance of risks of economic losses from accidents and disasters at potentially dangerous facilities as a result of the complex influence of natural, manmade and fire factors has been established. An analysis was carried out and proposals were developed to implement the key tasks of the state in the field of ensuring the protection of the population and territories of the country from disasters in order to ensure the stability of the economy. The organizational structure, division of tasks and functions between officials, crisis management structures and responding units were analyzed, taking into account the reduction in current financial costs. On the basis of a study of the peculiarities of the regions of the country, recommendations were formed to fulfill the necessary tasks by the anti-crisis management bodies in the field of reducing economic damage on the basis of preventing crisis situations and ensuring fire safety. It is proposed to organize the practical application of a complex automated security system based on modern developments with the application of improving the qualities and efficiency of anti-crisis management processes in order to increase economic efficiency. Initial data were formed to reduce potential threats of a natural, man-made, fire and other nature in the regions using financial and economic mechanisms. It is proposed to implement a set of priority measures to further improve and increase the potential of economic support for the anti-crisis management system. The materials of the article can be used in planning the main directions of the development of the regional population security system and the implementation of socio-economic development programs.

Sign in / Sign up

Export Citation Format

Share Document