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.

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 Surprising Behaviour of the Wageningen B-Screw Series Polynomials

2020 ◽  
Vol 8 (3) ◽  
pp. 211 ◽  
Author(s):  
Stephan Helma
Keyword(s):  
Reynolds Number ◽  
Open Water ◽  
Measured Data ◽  
Design Stage ◽  
Data Sets ◽  
Preliminary Design ◽  
Preliminary Design Stage ◽  
Torque Values ◽  
Thrust And Torque ◽  
Over Time

Undoubtedly, the Wageningen B-screw Series is the most widely used systematic propeller series. It is very popular to preselect propeller dimensions during the preliminary design stage before performing a more thorough optimisation, but in the smaller end of the market it is often used to merely select the final propeller. Over time, the originally measured data sets were faired and scaled to a uniform Reynolds number of 2 · 106 to increase the reliability of the series. With the advent of the computer, polynomials for the thrust and torque values were calculated based on the available data sets. The measured data are typically presented in the well-known open-water curves of thrust and torque coefficients K T and K Q versus the advance coefficient J . Changing the presentation from these diagrams to efficiency maps reveals some unsuspected and surprising behaviours, such as multiple extrema when optimising for efficiency or even no optimum at all for certain conditions, where an optimum could be expected. These artefacts get more pronounced at higher pitch to diameter ratios and low blade numbers. The present work builds upon the paper presented by the author at the AMT’17 and smp’19 conferences and now includes the extended efficiency maps, as suggested by Danckwardt, for all propellers of the Wageningen B-screw Series.

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.

Numerical Prediction of Propeller Characteristics

1973 ◽  
Vol 17 (01) ◽  
pp. 12-18
Author(s):  
Damon E. Cummings
Keyword(s):  
Open Water ◽  
Model Tests ◽  
Numerical Prediction ◽  
Water Model ◽  
Variable Pitch ◽  
Cavitation Inception ◽  
Fraction Distribution ◽  
Thrust And Torque ◽  
Ship Speed

A procedure is described for predicting the performance of a propeller numerically to within the accuracy of tunnel and open-water model tests. Given the geometry of the propeller, ship speed, wake fraction distribution and rpm, the thrust and torque characteristics are calculated. The procedure gives good results not only for "normal" propellers but also for such abnormal cases as a variable-pitch propeller operating at off-design pitches. The possibility exists of extension of the method for calculation of spindle torques, stresses, and cavitation inception.

scholarly journals Surprising Behaviour of the Wageningen B-screw Series Polynomials

2019 ◽  
Author(s):  
Stephan Helma
Keyword(s):  
Reynolds Number ◽  
Open Water ◽  
Measured Data ◽  
Design Stage ◽  
Data Sets ◽  
Preliminary Design ◽  
Preliminary Design Stage ◽  
Torque Values ◽  
Thrust And Torque ◽  
Over Time

Undoubtedly the Wageningen B-screw Series is the most widely used systematic propeller series. It is very popular to preselect propeller dimensions during the preliminary design stage, but often it is also used to merely select the final propeller. Over time the originally measured data sets were faired and scaled to a uniform Reynolds number (based on chord length and section advance speed) of 2·10⁶ to increase the reliability of the series. With the advent of the computer polynomials for the thrust and torque values were calculated from the available data sets. The measured data are typically presented in the well-known open-water curves of thrust and torque coefficients K_T and K_Q versus the advance coefficient J. Changing the presentation from open-water diagrams to efficiency maps reveals some unsuspected and surprising behaviours, such as multiple optima when optimizing for efficiency or even no optimum at all for certain conditions. These artefacts get more pronounced at higher pitch to diameter ratios and low blade numbers. The present work builds upon the paper presented by the author at the AMT'17 and smp'19 conferences and now includes the extended efficiency maps, as suggested by Danckwardt, for all propellers of the Wageningen B-screw Series.

An Experimental Study On The Relative Motions Between A Floating Harbour Transhipper And A Feeder Vessel In Regular Waves - Technical Note

2012 ◽  
Vol 154 (A2) ◽  
Keyword(s):  
Open Water ◽  
Technical Note ◽  
Scale Model ◽  
Regular Waves ◽  
Inclement Weather ◽  
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 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

scholarly journals Surprising Behaviour of the Wageningen B-screw Series Polynomials

2020 ◽  
Author(s):  
Stephan Helma
Keyword(s):  
Reynolds Number ◽  
Open Water ◽  
Measured Data ◽  
Design Stage ◽  
Data Sets ◽  
Preliminary Design ◽  
Preliminary Design Stage ◽  
Torque Values ◽  
Thrust And Torque ◽  
Over Time

Undoubtedly the Wageningen B-screw Series is the most widely used systematic propeller series. It is very popular to preselect propeller dimensions during the preliminary design stage before performing a more thorough optimization, but in the smaller end of the market it is often used to merely select the final propeller. Over time the originally measured data sets were faired and scaled to a uniform Reynolds number of 2·106 to increase the reliability of the series. With the advent of the computer, polynomials for the thrust and torque values were calculated based on the available data sets. The measured data are typically presented in the well-known open-water curves of thrust and torque coefficients KT and KQ versus the advance coefficient J. Changing the presentation from these diagrams to efficiency maps reveals some unsuspected and surprising behaviours, such as multiple optima when optimizing for efficiency or even no optimum at all for certain conditions. These artefacts get more pronounced at higher pitch to diameter ratios and low blade numbers. The present work builds upon the paper presented by the author at the AMT’17 and smp’19 conferences and now includes the extended efficiency maps, as suggested by Danckwardt, for all propellers of the Wageningen B-screw Series.

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.

Sign in / Sign up

Export Citation Format

Share Document