Shallow-water effects in ship model testing and at full scale

2008 ◽

Cited By ~ 1

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.

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Full-scale resistance prediction in finite waters: A study using computational fluid dynamics simulations, model test experiments and sea trial measurements

Proceedings of the Institution of Mechanical Engineers Part M Journal of Engineering for the Maritime Environment ◽

10.1177/1475090216642467 ◽

2016 ◽

Vol 231 (1) ◽

pp. 316-328

Author(s):

Max Haase ◽

Gary Davidson ◽

Jonathan Binns ◽

Giles Thomas ◽

Neil Bose

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Shallow Water ◽

Model Test ◽

Full Scale ◽

Finite Width ◽

Medium Speed ◽

Water Effects ◽

Computational Fluid Dynamics Simulations ◽

Dynamics Simulations

The development of large medium-speed catamarans aims increasing economic viability and reducing the possible negative influence on the environment of fast sea transportation. These vessels are likely to operate at hump speed where wave-making can be the dominating component of the total resistance. Shallow water may considerably amplify the wave-making and hence the overall drag force. Computational fluid dynamics is used to predict the drag force of medium-speed catamarans at model and full scale in infinite and restricted water to study the impact on the resistance. Steady and unsteady shallow-water effects that occur in model testing or full-scale operation are taken into account using computational fluid dynamics as they are inherently included in the mathematical formulations. Unsteady effects in the ship-model response were recorded in model test experiments, computational fluid dynamics simulations and full-scale measurements and found to agree with each other. For a medium-speed catamaran in water that is restricted in width and depth, it was found that computational fluid dynamics is capable of accurately predicting the drag with a maximum deviation of no more than 6% when compared to experimental results in model scale. The influences of restricted depth and width were studied using computational fluid dynamics where steady finite width effects in shallow water and finite depth effects at finite width were quantified. Full-scale drag from computational fluid dynamics predictions in shallow water ( h/L = 0.12 – 0.17) was found to be between full-scale measurements and extrapolated model test results. Finally, it is shown that current extrapolation procedures for shallow-water model tests over-estimate residuary resistance by up to 12% and underestimate frictional forces by up to 35% when compared to validated computational fluid dynamics results. This study concludes that computational fluid dynamics is a versatile tool to predict the full-scale ship resistance to a more accurate extent than extrapolation model test data and can also be utilised to estimate model sizes that keep finite-water effects to an agreed minimum.

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Shallow Water Current Loads on a LNG Carrier Using CFD

Volume 2: CFD and VIV ◽

10.1115/omae2015-41275 ◽

2015 ◽

Cited By ~ 1

Author(s):

Arjen Koop

Keyword(s):

Shallow Water ◽

Scale Effects ◽

Current Situation ◽

Full Scale ◽

Water Current ◽

Water Effects ◽

Basin Floor ◽

Flow Situation ◽

The Difference ◽

A Current

To determine shallow water effects on current loads for an LNG Carrier, CFD calculations with MARIN’s CFD code ReFRESCO have been carried out. The CFD results are compared to model tests carried out in MARIN’s Shallow Water Basin for the HAWAI JIP. The loads have been determined for three different water depth to draft ratio’s, from relatively deep water to shallow water. For all water depths the difference in CY coefficient between the CFD results and experiments is 5–10%. Furthermore, the blockage effects from basin side walls are investigated. For shallow water it was found that the blockage effects are significant, i.e. 30–50%, and that they vary for different current headings. For deeper water the blockage effects are smaller than 5%. The influence of “towing” versus a “current” flow situation is also studied. In the experiments the model is towed through the basin leading to a relative velocity between the model and the basin floor. It is found that for shallow water the results for the “tow” situation are 10% lower than for the “current” situation. Lastly, preliminary results for full scale are presented. At full scale the current coefficients are found to be lower than at model scale. However, more investigations should be carried out at full scale to be able to draw definite conclusions. From the results presented in this paper it is concluded that shallow water effects on current loads can be accurately obtained with CFD. Furthermore, blockage effects and the influence of “towing” versus a “current” situation have been quantified and a first study into scale effects has been presented.

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A Novel Approach to Turbulence Stimulation for Ship-Model Testing

10.21236/ada549033 ◽

2010 ◽

Author(s):

Jason C. Murphy

Keyword(s):

Model Testing ◽

Ship Model ◽

Novel Approach

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Ship Model Testing

10.21236/ada630949 ◽

2016 ◽

Author(s):

Richard A. Royce

Keyword(s):

Model Testing ◽

Ship Model

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Experimental Study of a Tanker Ship Squat in Shallow Water

Jurnal Teknologi ◽

10.11113/jt.v66.2477 ◽

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.

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