scholarly journals FLOW COMPUTATIONS NEARBY A STORM SURGE BARRIER UNDER CONSTRUCTION WITH TWO-DIMENSIONAL NUMERICAL MODELS

1986 ◽  
Vol 1 (20) ◽  
pp. 143
Author(s):  
H.E. Klatter ◽  
J.M.C. Dijkzeul ◽  
G. Hartsuiker ◽  
L. Bijlsma
Keyword(s):  
Numerical Model ◽  
Storm Surge ◽  
Field Data ◽  
Numerical Models ◽  
Flow Patterns ◽  
Scale Model ◽  
Energy Losses ◽  
Local Energy ◽  
Two Dimensional ◽  
Physical Scale

This paper discusses the application of two-dimensional tidal models to the hydraulic research for the storm surge barrier in the Eastern Scheldt in the Netherlands. At the site of the barrier local energy losses dominate the flow. Three methods are discussed for dealing with these energy losses in a numerical model based on the long wave equations. The construction of the storm surge barrier provided extensive field data for various phases of the construction of the barrier and these field data are used as a test case for the computation at methods developed. One method is preferred since it gives good agreement between computations and field data. The two-dimensional flow patterns, the discharge and the head-difference agree well,, The results of scale model tests were also available for comparison. This comparison demonstrated that depth-averaged velocities, computed by a two-dimensional numerical model, are as accurate as values obtained from a large physical scale model. Even compicated flow patterns with local energy losses and sharp velocity gradients compared well.

scholarly journals THE USE OF ARRAY PROCESSORS FOR NUMERICAL MODELLING OF TIDAL ESTUARY DYNAMICS

1980 ◽  
Vol 1 (17) ◽  
pp. 142
Author(s):  
D. Prandle ◽  
E.R. Funke ◽  
N.L. Crookshank ◽  
R. Renner
Keyword(s):  
Numerical Model ◽  
Numerical Modelling ◽  
Hybrid Model ◽  
Numerical Models ◽  
Computer Time ◽  
Scale Model ◽  
Hybrid Modelling ◽  
Tidal Propagation ◽  
Physical Scale ◽  
Array Processors

The use of array processors for the numerical modelling of estuarine systems is discussed here in the context of "hybrid modelling", however, it is shown that array processors may be used to advantage in independent numerical simulations. Hybrid modelling of tidal estuaries was first introduced by fiolz (1977) and later by Funke and Crookshank (1978). In a hybrid model, tidal propagation in an estuary is simulated by dynamically linking an hydraulic (or physical) scale model of part of the estuary to a numerical model of the remaining part in a manner such that a free interchange of flow occurs at the interface(s). Typically, the elevation of the water surface at the boundary of the scale model is measured and transmitted to the numerical model. In return, the flow computed at the boundary of the numerical model is fed directly into the scale model. This approach enables the extent of the scale model to be limited to the area of immediate interest (or to that area where flow conditions are such that they can be most accurately simulated by a scale model). In addition, since the region simulated by the numerical model can be extended almost indefinitely, the problems of spurious reflections from downstream boundaries can be eliminated. In normal use, numerical models are evaluated on the basis of computing requirements, cost and accuracy. The computer time required to simulate one tide cycle is, in itself, seldom of interest except in so far as it affects the above criteria. However in hybrid modelling this parameter is often paramount since concurrent operation of the numerical and scale models requires that the former must keep pace with the latter. The earlier hybrid model of the St. Lawrence (Funke and Crookshank, 1978) involved a one-dimensional numerical model of the upstream regions of the river. However, future applications are likely to involve extensive two-dimensional numerical simulation.

scholarly journals SIMULATION OF SANDFILL BUILDING STAGES WITH NUMERICAL FLOW MODELS

1986 ◽  
Vol 1 (20) ◽  
pp. 75
Author(s):  
G.J. Bosselaar ◽  
R.A.H. Thabet ◽  
A.J.G.M. Van Roermund ◽  
L. Bijlsma
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Flow Patterns ◽  
Two Dimensional ◽  
Integrated Models ◽  
Flow Models ◽  
Test Models ◽  
Physical Scale ◽  
Scale Models ◽  
Closure Operations

The paper describes the application of two dimensional vertically integrated models (WAQUA system) , the results being used for the calculation of sandlosses during sandfill closure operations. Investigations with test models, physical scale models as well as numerical models, are presented to prove that the WAQUA system is not only suitable for large scale applications, but also for the simulation of detailed flow patterns.

scholarly journals Flow patterns of shallow Palic Lake induced by the dominant winds

2012 ◽  
Vol 10 (1) ◽  
pp. 55-67
Author(s):  
Ljubomir Budinski ◽  
Djula Fabian
Keyword(s):  
Numerical Model ◽  
Flow Pattern ◽  
Coriolis Force ◽  
Wind Direction ◽  
Driving Forces ◽  
Open Water ◽  
Flow Patterns ◽  
Two Dimensional ◽  
Lake Model ◽  
Double Gyre

Studies of lake currents have highlighted that in case of stagnant waters winds are the dominant driving forces. This study is dealing with the influence of dominant winds on the flow pattern of Palic Lake. Action of steady winds of different directions has been tested on the lake by means of a two dimensional numerical model, while in addition to winds all other permanent factors like actual bathymetry, inflow and outflow as well the Coriolis force have been accounted for. The experiments have revealed that winds of different directions created corresponding characteristic flow patterns (in base plot), which were similar in cases of winds having opposite directions. However, in such cases the direction of flow was opposite. Moreover, the Palic Lake model produced the well known double-gyre flow pattern: in the coastal strip the direction of the current corresponded to the wind direction, while it was opposite in the domain of open water.

scholarly journals Modeling Storm Surge Attenuation by an Integrated Nature-Based and Engineered Flood Defense System in the Scheldt Estuary (Belgium)

2020 ◽  
Vol 8 (1) ◽  
pp. 27
Author(s):  
Sven Smolders ◽  
Maria João Teles ◽  
Agnès Leroy ◽  
Tatiana Maximova ◽  
Patrick Meire ◽  
...  
Keyword(s):  
Storm Surge ◽  
Flood Control ◽  
Storm Surges ◽  
Scheldt Estuary ◽  
Scale Model ◽  
Defense System ◽  
Height Reduction ◽  
Flood Defense ◽  
Physical Scale ◽  
Surge Height

There is increasing interest in the use of nature-based approaches for mitigation of storm surges along coasts, deltas, and estuaries. However, very few studies have quantified the effectiveness of storm surge height reduction by a real-existing, estuarine-scale, nature-based, and engineered flood defense system, under specific storm surge conditions. Here, we present data and modelling results from a specific storm surge in the Scheldt estuary (Belgium), where a hybrid flood defense system is implemented, consisting of flood control areas, of which some are restored into tidal marsh ecosystems, by use of culvert constructions that allow daily reduced tidal in- and outflow. We present a hindcast simulation of the storm surge of 6 December 2013, using a TELEMAC-3D model of the Scheldt estuary, and model scenarios showing that the hybrid flood defense system resulted in a storm surge height reduction of up to half a meter in the estuary. An important aspect of the work was the implementation of model formulations for calculating flow through culverts of restored marshes. The latter was validated comparing simulated and measured discharges through a physical scale model of a culvert, and through a real-scale culvert of an existing restored marsh during the storm surge.

3D numerical modeling of sediment handling techniques in a hydro power reservoir

2020 ◽  
Author(s):  
Diwash Lal Maskey ◽  
Dipesh Nepal ◽  
Daniel Herman ◽  
Gabriele Gaiti ◽  
Nils Rüther
Keyword(s):  
Numerical Model ◽  
Guide Vane ◽  
Scale Model ◽  
Bed Load ◽  
3D Numerical Modeling ◽  
Deposition Pattern ◽  
Flow Measurements ◽  
Reservoir Volume ◽  
Physical Scale ◽  
3D Numerical Model

<p>Sedimentation of small as well as large water storage reservoir has become a major issue. Due to the fact that we observe a 1% decrease of reservoir volume every year due to sedimentation and that the largest part of the reservoirs have been built between 70 and 40 years ago, many HPPs are confronted with the threatening scenario that soon the active storage and therefore their lifetime is dramatically diminished. Due to the above mentioned combination, active and sustainable sediment management has become the last option to retain or preferable enlarge the left-over reservoir volume. There are several options for a sustainable sediment handling, each for a different boundary condition, which must be evaluated carefully in order to be successful. For a successful choice, design and conduction of a sediment handling technique, usually a physical scale model will be conducted. Physical scale model have the advantage that there is a lot of experience in conducting these models and that they are illustrative. The disadvantage of scale models is that there are restrictions in the use of certain sizes of sediments due to scaling issues and that they are rather expensive.</p><p>This study attempt to use a 3D numerical model to overcome the above mentioned disadvantages and to serve as an additional source of alternatives in finding the right sediment handling techniques in reservoirs with high discharges of suspended and bed load. The goal is to simulate several flood events in order to gain insights in the current situation as well as to have a better understanding of the physical processes in the reservoir. This will support and positive influence the sustainable design of sediment handling techniques. The numerical model will be verified with flow measurements a physical model study and with bathymetry measurements from field observations. Based on the actual deposition pattern and the given input data, different sediment handling techniques are planned and conducted by means of the numerical model. The results show that the 3D numerical model is able to simulate sediment transport deposition pattern, bed load guide vane structures, as well as bed load diversion structures.</p>

scholarly journals Crustal Fault Zones (CFZ) as Geothermal Power Systems: A Preliminary 3D THM Model Constrained by a Multidisciplinary Approach

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-24
Author(s):  
Hugo Duwiquet ◽  
Laurent Guillou-Frottier ◽  
Laurent Arbaret ◽  
Mathieu Bellanger ◽  
Théophile Guillon ◽  
...  
Keyword(s):  
High Temperature ◽  
Numerical Model ◽  
Power Systems ◽  
Fault Zone ◽  
Field Data ◽  
Large Scale ◽  
Numerical Models ◽  
Massif Central ◽  
Temperature Anomalies ◽  
Stress Direction

The Pontgibaud crustal fault zone (CFZ) in the French Massif Central provides an opportunity to evaluate the high-temperature geothermal potential of these naturally permeable zones. Previous 2D modeling of heat and mass transfer in a fault zone highlighted that a subvertical CFZ concentrates the highest temperature anomalies at shallow depths. By comparing the results of these large-scale 2D numerical models with field data, the depth of the 150°C isotherm was estimated to be at a depth of 2.5 km. However, these results did not consider 3D effects and interactions between fluids, deformation, and temperature. Here, field measurements are used to control the 3D geometry of the geological structures. New 2D (thin-section) and 3D (X-ray microtomography) observations point to a well-defined spatial propagation of fractures and voids, exhibiting the same fracture architecture at different scales (2.5 μm to 2 mm). Moreover, new measurements on porosity and permeability confirm that the highly fractured and altered samples are characterized by large permeability values, one of them reaching 10-12 m2. Based on a thermoporoelastic hypothesis, a preliminary 3D THM numerical model is presented. A first parametric study highlights the role of permeability, stress direction, and intensity on fluid flow. In particular, three different convective patterns have been identified (finger-like, blob-like, and double-like convective patterns). The results suggest that vertical deformation zones oriented at 30 and 70° with respect to the maximum horizontal stress direction would correspond to the potential target for high-temperature anomalies. Finally, a large-scale 3D numerical model of the Pontgibaud CFZ, based on THM coupling and the comparison with field data (temperature, heat flux, and electrical resistivity), allows us to explore the spatial geometry of the 150°C isotherm. Although simplified hypotheses have been used, 3D field data have been reproduced.

Modeling and Experiments on an Oscillating Water Column Using a Self-Adaptive Air Turbine and Shutter

2013 ◽  
Author(s):  
Patrick Lorenz ◽  
Richard W. Kimball ◽  
Frank DiBella ◽  
Richard Smith ◽  
Scott Ring
Keyword(s):  
Numerical Model ◽  
Water Column ◽  
Potential Flow ◽  
Numerical Models ◽  
Air Flow ◽  
Chamber Pressure ◽  
Oscillating Water Column ◽  
Cavity Pressure ◽  
Wells Turbine ◽  
Physical Scale

This paper presents model-scale measurements and numerical models of a floating oscillating water column (OWC) system, consisting of an air cavity coupled with a Wells-type turbine energy extraction device. As waves travel through the OWC, air pressure cycles are generated. The oscillating water column captures the resulting pneumatic energy by directing the chamber pressure and air flow through the Wells turbine. A special feature of the system is a shuttering device that momentarily interrupts turbine air flow. The shuttering device is used to control the cavity pressure for optimum turbine performance. Shuttering in this manner can be shown to improve overall system efficiency up to 20% pressure. Physical scale models of the OWC system were tested in a wave tank at Maine Maritime Academy (MMA) at 1/30th scale as well as elastomeric diaphragm testing at 1/15th scale, under various conditions. Data from these tests, including cavity pressure response, turbine flow rate, and computed fluid power are discussed. In addition, numerical models of the system were developed using a parametric spring-mass-dashpot methodology and as well as a potential flow model derived for cavity geometry in a global wave field (see section 3). This paper describes the OWC system with adaptive shutter; comparison of experimental measurements to numerical model predictions; numerical model implementation and measurements of energy absorption/resonant effects within the chamber; and a potential flow derivation.

Cold Cap Grout Formulation for Waste Containment at DOE Site, Hanford, Washington

1991 ◽  
Vol 245 ◽  
Author(s):  
Lillian D. Wakeley ◽  
James J. Ernzen
Keyword(s):  
Numerical Models ◽  
Bentonite Clay ◽  
Department Of Energy ◽  
Scale Model ◽  
Natural Sand ◽  
Near Surface ◽  
Volume Stability ◽  
Performance Requirements ◽  
Physical Scale ◽  
Class F Fly Ash

ABSTRACTWES developed a grout to be used as a cold (non-radioactive) cap or void-fill material between the solidified low-level waste and the cover blocks of near-surface disposal vaults at the U.S. Department of Energy (DOE) Hanford Facility. The project consisted of formulation and evaluation of candidate grout, followed by a physical scale-model test to verify grout performance under project-specific conditions and provide data to verify numerical models of stresses and isotherms inside the Hanford demonstration vault. Evaluation of unhardened grout included segregation, bleed, flow, and working time. For hardened grout, strength, volume stability, thermal heat rise, and geochemical compatibility with surrogate wasteform grout were examined.The grout was formulated to accommodate unique environmental boundary conditions (vault temperature = 45 °C) and exacting regulatory requirements (mandating less than 0.1% shrinkage with no expansion and no bleeding); and to remain pumpable for a minimum 2 hr. A grout consisting of API Class H cement, an ASTM C 618 Class F fly ash, sodium bentonite clay, and a natural sand from the Hanford area met all performance requirements in laboratory studies.

Numerical Model of Natural River Flow by Unstructure Space-Time SE-CE Method

2011 ◽  
Vol 101-102 ◽  
pp. 392-395
Author(s):  
Ji Lun Miao ◽  
Xiao Xin Fei ◽  
Cheng Lin Huang
Keyword(s):  
Numerical Model ◽  
Shallow Water ◽  
Shallow Water Equations ◽  
Field Data ◽  
River Flow ◽  
Space Time ◽  
Two Dimensional ◽  
Proposed Model ◽  
Complex Boundaries ◽  
Natural Rivers

A new horizontal two-dimensional mathematic scheme namely space-time Conservation Element and Solution Element (CE-SE) is introduced in this paper. The CE-SE method has some features which space and time are unified and treated on the same footing, both local and global flux are enforced conservation. The proposed model is applied to solve the 2-D shallow water equations in the triangular mesh, and tested by using the field data in Yangzi River. It shows that the hydraulics characters in natural rivers which are with complex boundaries and topography can be well simulated by using this new method.

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