Experimental Study of a Tanker Ship Squat in Shallow Water

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Mohammadreza Fathi Kazerooni ◽  
Mohammad Saeed Seif
Keyword(s):  
Experimental Study ◽  
Shallow Water ◽  
Experimental Approach ◽  
Model Tests ◽  
Ship Hull ◽  
Experimental Results ◽  
Shallow Waters ◽  
Towing Tank ◽  
Ship Model

One of the phenomena restricting the tanker navigation in shallow waters is reduction of under keel clearance in the terms of sinkage and dynamic trim that is called squatting. According to the complexity of flow around ship hull, one of the best methods to predict the ship squat is experimental approach based on model tests in the towing tank. In this study model tests for tanker ship model had been held in the towing tank and squat of the model are measured and analyzed. Based on experimental results suitable formulae for prediction of these types of ship squat in fairways are obtained.

Study on vertical motion reduction of a trimaran based on collaborative controlled appendages

2020 ◽  
Vol 17 (6) ◽  
pp. 172988142097677
Author(s):  
Zhilin Liu ◽  
Linhe Zheng ◽  
Guosheng Li ◽  
Shouzheng Yuan ◽  
Songbai Yang
Keyword(s):  
Experimental Study ◽  
Vertical Motion ◽  
Model Tests ◽  
Wave Period ◽  
Regular Waves ◽  
Towing Tank ◽  
Vertical Stability ◽  
Stabilization Control ◽  
Stability Performance

In recent years, the trimaran as a novel ship has been greatly developed. The subsequent large vertical motion needs to be studied and resolved. In this article, an experimental study for a trimaran vertical stabilization control is carried out. Three modes including the bare trimaran (the trimaran without appendages, the trimaran with fixed appendages, and the trimaran with controlled appendages) are performed through model tests in a towing tank. The model tests are performed in regular waves. The range of wave period is 2.0–4.0 s, and the speed of the carriage is 2.93 and 6.51 m/s. The results of the three modes show the fixed appendages and the actively controlled appendages are all effective for the vertical motion reduction of the trimaran. Moreover, the controlled appendages are more effective for the vertical stability performance of the trimaran.

Experimental Analysis of Five Keel-Hull Combinations

1985 ◽  
Author(s):  
J. Gerritsma ◽  
J. A. Keuning
Keyword(s):  
Experimental Analysis ◽  
Model Tests ◽  
Experimental Results ◽  
Forward Speed ◽  
Hull Form ◽  
Towing Tank ◽  
Side Force ◽  
Performance Predictions

Model tests with five different keels in combination with one particular hull form have been carried out in the Delft Towing Tank. The variations include a plain deep keel, a keel-centre board, a plain restricted draft keel,a "Scheel" keel and a "winglet" keel. Based on the experimental results performance predictions are given for a 63 ft yacht for windspeeds up to 25 knots. The measured side force and resistance as a function of heeling angle, leeway angle and forward speed are used to analyse the relative merits of the considered keel-hull combinations.

Studies on Resonant Water Motion Between a Ship and a Fixed Terminal in Shallow Water

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Trygve Kristiansen ◽  
Odd M. Faltinsen
Keyword(s):  
Shallow Water ◽  
Vertical Wall ◽  
Model Tests ◽  
Ship Model ◽  
Wave Flume ◽  
Wave Elevation ◽  
Resonant Behavior ◽  
Liquid Natural Gas ◽  
Sharp Corners ◽  
Hydrodynamical Problem

This work focuses on the hydrodynamical problem of a Liquid Natural Gas (LNG) carrier near a Gravity Based Structure (GBS) -type offshore terminal subject to incoming waves in medium deep to shallow water conditions. The work is restricted to 2D, and the ship is restrained from moving. The resonant behavior of the fluid in the gap between the ship and the terminal is investigated. The problem is investigated by means of a numerical model and model tests. Potential theory is assumed, and a linear as well as a nonlinear time-domain numerical wavetank based on a boundary element method with a mixed Eulerian–Lagrangian approach is implemented for this purpose. Model tests (near 2D) of a midship section near a vertical wall are carried out in a 26.5m long and 0.595m wide wave flume in model scale 1:70. In full scale the ship beam is 45m and the ship draft is 12m. The ship model is constructed in such a way as to avoid flow separation, i.e., no sharp corners. Several parameters are varied: water depth, wave period, and wave steepness. Wave elevation is measured at 12 locations.

Experimental Study of Ship Response due to Internal Viscous Cargo Motions

2018 ◽  
Author(s):  
Virginie Baudry ◽  
Jean-Marc Rousset
Keyword(s):  
Experimental Study ◽  
Free Surface ◽  
Viscous Fluid ◽  
Fresh Water ◽  
Iron Ore ◽  
Experimental Approach ◽  
Viscous Fluids ◽  
Maritime Industry ◽  
Bulk Carrier ◽  
Ship Model

Potential liquefaction of some cargoes (Nickel ore, iron ore, ...) is a major risk for the maritime industry. The difficulties to simulate accurately the behaviour of these materials as well as their interaction with a bulk carrier model leaded us to use a non-Newtonian highly viscous fluid to model a liquefied ore. An experimental approach is presented in this paper. Roll responses of a ship model as well as details on the internal free surface behaviours are investigated for different loading conditions: solid cargo, fresh water and viscous fluids.

Experimental Study of the Effect of the Pontoon Dimensions on the Flow-Induced Motions (FIM) of a Semi-Submersible Platform With Four Square Columns

2020 ◽  
Author(s):  
Rodolfo T. Gonçalves ◽  
Hideyuki Suzuki ◽  
Matheus A. Marques ◽  
Leandro S. P. Silva ◽  
Chenling Tian ◽  
...  
Keyword(s):  
Experimental Study ◽  
Fatigue Life ◽  
Transverse Direction ◽  
Vertical Direction ◽  
Model Tests ◽  
Mooring Line ◽  
Towing Tank ◽  
Spacing Ratio ◽  
Floating System ◽  
Four Square

Abstract The Flow-Induced Motions (FIM) is an essential topic on multi-column platforms due to the effect on the mooring line fatigue life. Vortex-Induced Motions (VIM) or galloping behavior can be observed for an array of four columns with square sections. The presence of pontoons showed to be important for changing the flow around the array and promoting different amplitude behaviors of the motions in the transverse direction mainly. This article aims to understand the effect of the presence of four pontoons on the FIM of a semi-submersible platform (SS) with four square section columns. Model tests of a floating system supported elastically utilizing four springs were performed in a towing tank. Five different pontoon ratios were tested, namely P/L = 0, 0.25, 0.50, 0.75, and 1.00; where P is the pontoon height (the dimension in the vertical direction), and L is the length of the square column face. The draft condition was kept constant as H/L = 1.5; where H is the draft of the platform. The spacing ratio of the columns was S/L = 4; where S is the distance between column centers. Two incidence angles of the current were carried out, namely 0 and 45 degrees. The amplitudes in the transverse direction (direction perpendicular to the incidence current) decreased by increasing the pontoon ratio for 0 and 45-deg incidences. The pontoons positioned aligned to the flow significantly reduced the amplitudes in the transverse direction since the pontoon presence in this position modified the incident wake in the downstream columns. The pontoon presence needs to be well investigated to choose the best condition to avoid raising the FIM or mitigating the FIM.

Advance Speed-Hull-Pump-Jet Interactions in Small ASV

2020 ◽  
Author(s):  
Angelo Odetti ◽  
Marco Altosole ◽  
Marco Bibuli ◽  
Gabriele Bruzzone ◽  
Massimo Caccia ◽  
...  
Keyword(s):  
Shallow Water ◽  
Technological Development ◽  
Hydrodynamic Characteristics ◽  
Shallow Waters ◽  
Towing Tank ◽  
Remote Areas ◽  
Autonomous Surface Vehicle ◽  
Jet Interactions ◽  
Advance Speed

This paper is related to the technological development of an innovative small-size Autonomous Surface Vehicle designed to meet the requirement of accessing, monitoring and protecting the shallow waters peculiar of the Wetlands. The first prototype of a fully electric, modular, portable, lightweight, and highly-controllable Autonomous Surface Vehicle (ASV) for extremely shallow water and remote areas, namely SWAMP, was developed by CNR-INM and DITEN-Unige. This catamaran is equipped with four azimuth Pump-Jet Modular (PJM) actuators designed for small-size (1 to 1.5 m long) ASV. The main advantage of Pump-Jet thrusters is that they are flush with the hull, thus minimizing the risks of damages due to possible grounding. This system is used to increase the manoeuvrability in narrow spaces and to increase the spacial resolution by allowing the access also in extremely shallow waters with smaller risk of loosing manoeuvrability. The knowledge of the hydrodynamic characteristics of the thruster and of the vessel allows to partly or fully identifying the vessel for a better controllability. With this aim a series of tests have been conducted in the DITEN towing tank. In particular advance resistance on the SWAMP hull in deep and shallow water, bollard pull and self-propelling tests with the Pump-Jet Module working have been carried out. The results of the tests with the effects of advance speed on the PJM performance is reported in this paper together with the description of the modelling of the thruster itself.

Moving PIV/LDV System for Various Ship Model Tests in a Towing Tank

2010 ◽  
Author(s):  
Aria Yuliartha ◽  
◽  
Che-Chun Chang ◽  
Shi-tai Jian ◽  
Sheng-Jie Shih ◽  
...  
Keyword(s):  
Model Tests ◽  
Towing Tank ◽  
Ship Model

Resonant Water Motion Between a Ship and a Terminal in Shallow Water

2007 ◽  
Author(s):  
Trygve Kristiansen ◽  
Odd M. Faltinsen
Keyword(s):  
Shallow Water ◽  
Time Domain ◽  
Vertical Wall ◽  
Model Tests ◽  
Ship Model ◽  
Wave Flume ◽  
Wave Elevation ◽  
Water Conditions ◽  
Sharp Corners ◽  
Hydrodynamical Problem

This work focus on the hydrodynamical problem of an LNG carrier near a GBS-type offshore terminal subject to incoming waves in medium deep to shallow water conditions. The work is restricted to 2D and the ship is restrained from moving. The resonant behaviour of the fluid in the gap between the ship and the terminal is investigated. The problem is investigated by means of a numerical model and model tests. Potential theory is assumed and a linear as well as a nonlinear time-domain numerical wavetank based on a boundary element method with a Mixed Eularian-Lagrangian approach is implemented for this purpose. Model tests (near 2D) of a mid-ship section near a vertical wall is carried out in a 26.5m long and 0.595m wide wave flume in model scale 1:70. In full scale the ship beam is 45m and the ship draft 12m. The ship model is constructed in such a way as to avoid flow separation, i.e. no sharp corners. Several parameters are varied: Water depth, wave period and wave steepness. Wave elevation is measured at twelve locations.

Innovative Ice Protection for Shallow Water Drilling: Part II — SIB Model Testing in Ice

2008 ◽  
Author(s):  
Arne Gu¨rtner ◽  
Ove Tobias Gudmestad
Keyword(s):  
Shallow Water ◽  
Conceptual Design ◽  
Caspian Sea ◽  
Companion Paper ◽  
Model Testing ◽  
Model Tests ◽  
Full Scale ◽  
Ship Model ◽  
Water Developments ◽  
Broken Ice

Model tests on the Shoulder Ice Barrier (SIB) were performed in the large ice tank of the Hamburg Ship Model Basin (HSVA) during July 2007. The concept of the SIB has previously been presented in a companion paper under the same title at the OMAE 2006 (Gu¨rtner et al., 2006). Model tests were performed to investigate the conceptual design and force conditions under ice impact. Design conditions for the Northern Caspian Sea were assumed for the model tests. The characteristic shoulder sections’ inclination has been varied to investigate their contribution towards stabilizing broken ice and to prevent ice from over-riding. Ice up-riding onto the barrier contributes towards increased vertical forces. The global vertical forces showed to be higher than the global horizontal forces, and in particular when ice grounding was observed. Even under extreme rubble heights of up to 9.4 m (full scale), ice overtopping the structure was effectively prevented. The SIB showed the potential to be utilized as ice protection structure for future shallow water developments.

Experimental Study of Wave Forces on Vertical Cylinders in Shallow Waters

2007 ◽  
Author(s):  
Rujian Ma ◽  
Guixi Li ◽  
Dong Zhao ◽  
Jungang Wang
Keyword(s):  
Experimental Study ◽  
Shallow Water ◽  
Water Waves ◽  
High Reliability ◽  
Shallow Waters ◽  
Wave Forces ◽  
Shallow Water Waves ◽  
Wave Channel ◽  
Vertical Cylinders ◽  
Force Calculation

An experimental study of wave forces on the vertical cylinders in shallow waters was carried out in a wave channel. The wave parameters, wave forces and wave pressures are measured and studied in the paper. The study indicates that the distribution of wave pressures of the shallow water waves can be described by an exponential function with respect to water depth. The maximum surface elevation for shallow water waves can be estimated using the significant wave height. The wave pressure around circumference can be expressed as a simple form of cosine function. An experimental formula for the calculation of wave forces on vertical cylinders is proposed. As compared with test data, the predicted wave forces showed good agreement and high reliability. The calculated wave forces by different wave theories are less than those of the proposed method. Therefore, the wave force calculation method for shallow water waves should be modified for engneering applications.

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