scholarly journals ADVANCED MODELLING OF WAVE PENETRATION IN PORTS

2020 ◽  
pp. 18
Author(s):  
Konstantina Aikaterini Maroudi ◽  
Sebastiaan P. Reijmerink
Keyword(s):  
Numerical Model ◽  
Wave Process ◽  
Model Tests ◽  
Benchmark Dataset ◽  
Scale Model ◽  
Simplified Models ◽  
Port Operations ◽  
Physical Scale ◽  
Hydrostatic Model

Wave penetration is a challenge for port engineers as it governs vessels' safe sailing and mooring and unequivocally regulates the handling of port operations. A complete way to describe this phenomenon is by a physical scale model. However, this approach can be time consuming and expensive, therefore the use of a numerical model is a valid alternative. In this study, wave penetration is simulated with the non-hydrostatic model SWASH (Zijlema, 2011). To validate the model, the output of an open benchmark dataset of physical scale model tests (Van der Ven, 2018) is used. This study evaluates to what degree SWASH models correctly simulate wave penetration per wave process, separately in simplified models and in combination in the full harbour layout, to identify their role in the model accuracy.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/Y8ds-sW4VIQ

AN EXPERIMENTAL STUDY ON THE RELATIVE MOTIONS BETWEEN A FLOATING HARBOUR TRANSHIPPER AND A FEEDER VESSEL IN REGULAR WAVES

2021 ◽  
Vol 154 (A2) ◽  
Author(s):  
G J Macfarlane ◽  
T Lilienthal ◽  
R J Ballantyne ◽  
S Ballantyne
Keyword(s):  
Open Water ◽  
Scale Model ◽  
Regular Waves ◽  
Inclement Weather ◽  
Port Operations ◽  
Physical Scale ◽  
Feeder Vessel ◽  
Primary Advantage ◽  
Exposed Location ◽  
Relative Motions

The Floating Harbour Transhipper (FHT) is a pioneering logistics solution that was designed to meet the growing demands for coastal transhipment in the mining sector as well as commercial port operations. The primary advantage of the FHT system is that it can reduce transhipment delays caused by inclement weather, by reducing relative motions between the FHT and feeder vessel. The feeder is sheltered when inside the FHT well dock when compared to the more exposed location when a feeder is in a traditional side-by-side mooring arrangement. This paper discusses previously published studies into the relative motions of vessels engaged in side-by-side mooring arrangements and also presents details and results from a series of physical scale model experiments. In these experiments, both side-by-side and aft well dock mooring arrangements are investigated. The results provide strong evidence that the FHT well dock concept can significantly reduce the heave, pitch and roll motions of feeder vessels when transhipping in open seas – this being the cornerstone of any successful open water transhipment operation.

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.

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>

Ship Movements’ Analysis in a Physical Scale Model

2017 ◽  
Vol 372 ◽  
pp. 132-141
Author(s):  
Liliana Pinheiro ◽  
Joana Simão ◽  
João Alfredo Santos ◽  
Conceição Juana Fortes
Keyword(s):  
Physical Model ◽  
Fiber Optic ◽  
Transfer Functions ◽  
Model Tests ◽  
Scale Model ◽  
Physical Model Tests ◽  
Physical Scale ◽  
Wave Heights ◽  
Wave Conditions ◽  
The Waves

A set of physical model tests was run in to characterize the ship’s response to different wave conditions going from frequently-occurring conditions up to extreme ones. Several wave heights, periods and directions were generated. The waves around the ship were measured with probes and the movements of the ship were measured with a fiber-optic gyrocompass. Transfer functions are established and compared with numerical ones obtained with the WAMIT model.

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.

New Approach of Deep Sea Dredging

2011 ◽  
Author(s):  
Ewout van Duursen ◽  
Mark Winkelman
Keyword(s):  
Numerical Model ◽  
Deep Sea ◽  
Idle Time ◽  
Model Tests ◽  
Scale Model ◽  
Water Mixture ◽  
Research Project ◽  
New Approach ◽  
Return Of Investment ◽  
Large Investment

A new approach of trailing suction dredging is presented. This approach is especially useful for dredging at depths over 100m. Normally a Jumbo Trailing Suction Hopper Dredger is used for dredging at depths of over 100m. This requires a large investment. The expensive dredging equipment is only used while dredging. This equipment is mainly “dead cargo” when sailing to the place of delivering the sand. Our new approach requires a significant lower investment. As the dredging equipment is used continuously, idle time is decreased and time for return of investment is shortened. The dredging depth is independent of the length of the trailing suction pipe and thus the length of the ship, unlike a normal Trailing Suction Hopper Dredger. Our approach consists of modular dredging equipment placed on e.g. a standard Platform Supply Vessel. By using the dredging equipment on this vessel, standard barges are continuously filled with sand. The dredging equipment consists of a submersible dredging unit connected to a hose. This dredging unit is suspended by wires from the Platform Supply Vessel. It is lowered to the required dredging depth by winches. The application of the dredging unit is like a normal Trailing Suction Hopper Dredger. The barges are loaded while sailing along the Platform Supply Vessel. The position of the dredging unit is constantly monitored. An extensive research project is initiated to develop this concept. Several scale model tests are performed at MARIN. Also a numerical model was designed. Extensive tests were performed on the hose. Another test was performed at TU Delft to investigate the transport of sand/water mixture through a hose stored on a reel. All this research has resulted in a reliable, inexpensive system to dredge at sea at great depths over 100m.

Thruster-Wave Interaction During DP Stationkeeping: Model Tests in Open Water and Under a Ship Hull

2017 ◽  
Author(s):  
Hans Cozijn ◽  
Jin Woo Choi ◽  
Young-Jun You
Keyword(s):  
Wave Interaction ◽  
Open Water ◽  
Model Tests ◽  
Wave Frequency ◽  
Scale Model ◽  
Regular Wave ◽  
Physical Scale ◽  
Torque Values ◽  
Thrust And Torque ◽  
Change In Mean

Wave orbital motions may cause variations in the inflow conditions of thrusters, resulting in variations in thrust and torque. Physical scale model tests were carried out to investigate these thruster-wave interaction effects, with an azimuthing thruster running at constant RPMs. The observed effects include a change in mean thrust and torque values, as well as wave frequency variations. The test conditions were systematically varied to investigate the effects of the incoming waves, the presence of the hull and the vessel motions. First, measurements were carried out on an azimuthing thruster in open water conditions. The thrust and torque in regular waves were compared with bollard pull conditions. Second, measurements were carried out on the azimuthing thruster under the hull of a vessel, which was rigidly connected to the basin carriage. Again, regular wave tests were performed, showing the effect of the presence of the hull. Third, measurements were carried out on the same azimuthing thruster under the hull of the vessel in a soft-mooring system. This kept the vessel in position and at the required heading, while allowing unrestricted wave frequency motions. Again, regular wave tests were performed, now showing the combined effects of the passing waves, the presence of the vessel hull and the vessel motions.

Advanced modelling of wave penetration in ports

2020 ◽  
Author(s):  
Konstantina Aikaterini Maroudi ◽  
Sebastiaan Reijmerink
Keyword(s):  
Steady State ◽  
Wave Height ◽  
Wave Process ◽  
Breaking Waves ◽  
Scale Model ◽  
Main Process ◽  
Horizontal Distance ◽  
Model Stability ◽  
State Wave ◽  
Physical Scale

<p>Wave penetration is a challenge for hydraulic engineers as it governs vessels’ sailing and mooring and regulates port operations. A complete approach to describe this phenomenon is by a physical scale model, which is time consuming and expensive. Therefore, a numerical model is a valid alternative. In this study, wave penetration is simulated with the non-hydrostatic model SWASH (Zijlema, 2011). To validate the model, part of an open benchmark dataset of physical scale model tests (Deltares, 2016) is used. This research addresses regular waves conditions and a simple harbour basin layout, in which reflection and diffraction are the main wave processes. This study assesses SWASH’s capability to model these processes, separately and in combination, in the full harbour layout.</p><p>1. Methodology</p><p>Reflection outside and inside the harbour is studied by two simplified 1D SWASH models, while diffraction inside the harbour by a simplified 2D model. The final SWASH model represents the full harbour layout. In all the models the water level time series at the output locations are compared qualitatively to the respective series measured at the wave gauges. Moreover, the measured steady state wave height is compared to the SWASH outputs. The “Difference”, Eq. (1), is computed to evaluate the model accuracy and to quantify the relative importance of each wave process.</p><p>Difference/diff.=(H<sub>SWASH,mean</sub>-H<sub>measured,mean</sub>)/H<sub>measured,mean  </sub>(1)</p><p>Where H<sub>SWASH,mean </sub>; H<sub>measured,mean </sub>: mean steady state wave height obtained by SWASH or measured respectively [m].</p><p>2. Results</p><p>Although the reflection trends are reproduced qualitatively in SWASH, the exact steady state wave height values may deviate significantly (diff.>30%). Moreover, the initial diffraction trends are also identified in SWASH despite their short duration in the measurements. Regarding the steady state wave height, diffraction influences considerably the total measured wave penetration inside the harbour. In the final SWASH model, the overall changes in the wave height are reproduced by SWASH. The agreement between the measured and the computed wave height is good at many output locations (diff.<10%). However, at some locations the accuracy is low (diff.>40%), owing to standing wave patterns which change fast within a short horizontal distance. Thus, the wave height can vary significantly at the area close to a specific wave gauge.  Finally, for relatively high waves and/or breaking waves, numerical instabilities are detected. Higher spatial resolution is required to capture such phenomena.</p><p>3. Conclusions</p><p>The study shows SWASH capability to reproduce qualitatively the most important reflection and diffraction trends. To a large extend, diffraction is the main process determining the wave height inside the harbour; reflection at the harbour end comes second. Outside the harbour, reflection off a quay wall is the dominant process, while reflection off a gravel slope is noteworthy. All in all, it is concluded that for non-breaking, relatively low waves, SWASH accuracy in modelling wave penetration is sufficient for engineering purposes. With further validation to guarantee the model stability, the implemented methodology can be a useful tool to understand the performance of SWASH in modeling wave penetration per wave process and in combination.</p>

scholarly journals Multiphasic Study of Fluid-Dynamics and the Thermal Behavior of a Steel Ladle during Bottom Gas Injection Using the Eulerian Model

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1082
Author(s):  
Antonio Urióstegui-Hernández ◽  
Pedro Garnica-González ◽  
José Ángel Ramos-Banderas ◽  
Constantin Alberto Hernández-Bocanegra ◽  
Gildardo Solorio-Díaz
Keyword(s):  
Heat Exchange ◽  
Thermal Behavior ◽  
Gas Flow ◽  
Fluid Dynamic ◽  
Steel Slag ◽  
Scale Model ◽  
Discrete Ordinates ◽  
Transfer Model ◽  
Steel Ladle ◽  
Physical Scale

In this work, the fluid dynamic and thermal behavior of steel was analyzed during argon gas stirring in a 140-t refining ladle. The Eulerian multiphase mathematical model was used in conjunction with the discrete ordinates (DO) thermal radiation model in a steel-slag-argon system. The model was validated by particle image velocimetry (PIV) and the analysis of the opening of the oil layer in a physical scale model. The effect of Al2O3 and Mg-C as a refractory in the walls was studied, and the Ranz-Marshall and Tomiyama models were compared to determine the heat exchange coefficient. The results indicated that there were no significant differences between these heat exchange models; likewise, the radiation heat transfer model adequately simulated the thermal behavior according to plant measurements, finding a thermal homogenization time of the steel of 2.5 min for a gas flow of 0.45 Nm3·min−1. Finally, both types of refractory kept the temperature of the steel within the ranges recommended in the plant; however, the use of Al2O3 had better heat retention, which would favor refining operations.

scholarly journals EXTREME WAVE PRESSURES AND LOADS ON A PILE-SUPPORTED WHARF DECK - INFLUENCES OF AIR GAP AND WAVE DIRECTION

2018 ◽  
pp. 5
Author(s):  
Andrew Cornett
Keyword(s):  
Offshore Structures ◽  
Model Tests ◽  
Scale Model ◽  
Extreme Waves ◽  
Wave Direction ◽  
Coastal Structures ◽  
Extreme Wave ◽  
Wave Impact ◽  
The Past ◽  
Water Depths

Many deck-on-pile structures are located in shallow water depths at elevations low enough to be inundated by large waves during intense storms or tsunami. Many researchers have studied wave-in-deck loads over the past decade using a variety of theoretical, experimental, and numerical methods. Wave-in-deck loads on various pile supported coastal structures such as jetties, piers, wharves and bridges have been studied by Tirindelli et al. (2003), Cuomo et al. (2007, 2009), Murali et al. (2009), and Meng et al. (2010). All these authors analyzed data from scale model tests to investigate the pressures and loads on beam and deck elements subject to wave impact under various conditions. Wavein- deck loads on fixed offshore structures have been studied by Murray et al. (1997), Finnigan et al. (1997), Bea et al. (1999, 2001), Baarholm et al. (2004, 2009), and Raaij et al. (2007). These authors have studied both simplified and realistic deck structures using a mixture of theoretical analysis and model tests. Other researchers, including Kendon et al. (2010), Schellin et al. (2009), Lande et al. (2011) and Wemmenhove et al. (2011) have demonstrated that various CFD methods can be used to simulate the interaction of extreme waves with both simple and more realistic deck structures, and predict wave-in-deck pressures and loads.

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