Surface Flow Measurement using VHF Ocean Radar in a Stratified Coastal Water and Data Assimilation into a 3-D Baroclinic Flow Model

2002 ◽  
Vol 44 (1) ◽  
pp. 67-90
Author(s):  
Masahide Ishizuka ◽  
Keiji Nakatsuji
Keyword(s):  
Data Assimilation ◽  
Coastal Water ◽  
Flow Measurement ◽  
Flow Model ◽  
Surface Flow ◽  
Baroclinic Flow ◽  
Ocean Radar

Surface flow model: inverse problems and predictions

2002 ◽  
Vol 25 (3) ◽  
pp. 317-324 ◽  
Author(s):  
Luther W. White ◽  
Baxter Vieux ◽  
David Armand
Keyword(s):  
Inverse Problems ◽  
Flow Model ◽  
Surface Flow ◽  
Model Inverse

Multi-objective optimisation of cost–benefit of urban flood management using a 1D2D coupled model

2011 ◽  
Vol 63 (5) ◽  
pp. 1053-1059 ◽  
Author(s):  
S. W. Delelegn ◽  
A. Pathirana ◽  
B. Gersonius ◽  
A. G. Adeogun ◽  
K. Vairavamoorthy
Keyword(s):  
Flow Model ◽  
Coupled Model ◽  
Cost Benefit ◽  
Flood Management ◽  
Flood Damage ◽  
Surface Flow ◽  
Nsga Ii ◽  
Urban Flood ◽  
Multi Objective ◽  
Evolutionary Optimisation

This paper presents a multi-objective optimisation (MOO) tool for urban drainage management that is based on a 1D2D coupled model of SWMM5 (1D sub-surface flow model) and BreZo (2D surface flow model). This coupled model is linked with NSGA-II, which is an Evolutionary Algorithm-based optimiser. Previously the combination of a surface/sub-surface flow model and evolutionary optimisation has been considered to be infeasible due to the computational demands. The 1D2D coupled model used here shows a computational efficiency that is acceptable for optimisation. This technological advance is the result of the application of a triangular irregular discretisation process and an explicit finite volume solver in the 2D surface flow model. Besides that, OpenMP based parallelisation was employed at optimiser level to further improve the computational speed of the MOO tool. The MOO tool has been applied to an existing sewer network in West Garforth, UK. This application demonstrates the advantages of using multi-objective optimisation by providing an easy-to-comprehend Pareto-optimal front (relating investment cost to expected flood damage) that could be used for decision making processes, without repeatedly going through the modelling–optimisation stage.

Transient hyporheic exchange during rainfall events in a gaining stream: Field investigation, conceptual model, and numerical interpretation

2020 ◽  
Author(s):  
Chengpeng Lu ◽  
Keyan Ji ◽  
Yong Zhang ◽  
Jan Fleckenstein ◽  
Chunmiao Zheng ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Conceptual Model ◽  
Hyporheic Zone ◽  
Flow Model ◽  
Surface Flow ◽  
Hyporheic Exchange ◽  
Biogeochemical Processes ◽  
Cross Sectional ◽  
Rainfall Events ◽  
Hyporheic Flow

<p>Hyporheic exchange is transient in nature, considering the temporal fluctuations in hydrological and/or biogeochemical conditions in surface water and groundwater (SW/GW).  Efforts are needed to further identify the patterns and driving mechanisms of transient hyporheic exchange.  This study combined a reach-scale field survey and numerical modeling analysis to reveal the pattern of transient hyporheic exchange during rainfall events in the Zhongtian River, southeast of China. Field observations revealed hydrodynamic properties and temperature variations in SW/GW, suggesting that the regional groundwater recharged the study reach.  A one-dimensional heat transport solution was built and used to generate the planar and cross-sectional hyporheic flow fields. A two-step numerical modeling procedure, including a hydraulic surface flow model and a groundwater flow model, was then used to simulate the observed flow system. The hyporheic exchange exhibited strong temporal evolution, as indicated by the rainfall event-driven hyporheic exchange, the depth-dependent hysteretic response to rainfall, and the area of local downwelling flow increasing with rainfall. Dynamics of the hyporheic exchange in the study reach, therefore, significantly changed in space and time due to rainfall. The reversal of hydraulic gradient and transient hyporheic exchange were observed and validated using the numerical simulation. Anisotropic hydraulic conductivity is the key to generate transient hyporheic exchange. A revised conceptual model was used to interpret the observed temporal patterns in hyporheic exchange  The pattern of transient hyporheic exchange indicates that transient hyporheic exchange only appears after an increased phase of river stage but does not last for a long time. The temporal pattern of hyporheic exchange can significantly affect the evolution of biogeochemical processes in the hyporheic zone for a gaining stream by, for example, temporally facilitating special biogeochemical processes.</p>

Simulation of pollutant dispersion of a free surface flow in coastal water

2015 ◽  
Vol 108 ◽  
pp. 81-97 ◽  
Author(s):  
Sonia Ben Hamza ◽  
Sabra Habli ◽  
Nejla Mahjoub Saïd ◽  
Hervé Bournot ◽  
Georges Le Palec
Keyword(s):  
Free Surface ◽  
Coastal Water ◽  
Pollutant Dispersion ◽  
Free Surface Flow ◽  
Surface Flow

A Two-Phase Flow Model with VOF for Free Surface Flow Problems

2012 ◽  
Vol 232 ◽  
pp. 279-283 ◽  
Author(s):  
Wei Zhang ◽  
You Hong Tang ◽  
Cheng Bi Zhao ◽  
Cheng Zhang
Keyword(s):  
Free Surface ◽  
Flow Model ◽  
Two Phase Flow ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Phase Model ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Problems ◽  
Fluid Sloshing

A numerical model based on the two-phase flow model for incompressible viscous fluid with a complex free surface has been developed in this study. The two-step projection method is employed to solve the Navier–Stokes equations in the numerical solutions, and finite difference method on a staggered grid is used throughout the computation. The two-order accurate volume of fluid (VOF) method is used to track the distorted and broken free surfaces. The two-phase model is first validated by simulating the dam break over a dry bed, in which the numerical results and experimental data agree well. Then 2-D fluid sloshing in a horizontally excited rectangular tank at different excitation frequencies is simulated using this two-phase model. The results of this study show that the two-phase flow model with VOF method is a potential tool for the simulation of nonlinear fluid sloshing. These studies demonstrate the capability of the two-phase model to simulate free surface flow problems with considering air movement effects.

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