Sailing Yacht Performance in Calm Water and in Waves

1993 ◽  
Author(s):  
J. Gerritsma ◽  
J. A. Keuning ◽  
A. Versluis
Keyword(s):  
Model Experiment ◽  
Irregular Waves ◽  
Current Interest ◽  
Added Resistance ◽  
Hull Form ◽  
Wide Range ◽  
Calm Water ◽  
Added Resistance In Waves ◽  
Sailing Yacht ◽  
Calculated Analysis

The Delft systematic Yatch Hull Series has been extended to a total of 39 hull form variations, covering a wide range of length displacement ratios and other form of parameters. The total set of model experiment results, upright and heeled resistance as well as sideforce and stability, had been analysed and polynomial expressions to approximate these quantities are presented. In view of the current interest in the performance of sailing yachts in waves, the added resistance in irregular waves of 8 widely different hull variations has been calculated. Analysis of the results shows that the added resistance in waves strongly depends on the product of displacement-length ratio and the gyradius of the pitching motion.

Experimental investigation on the added resistance of modified KVLCC2 hull forms with different bow shapes

2016 ◽  
Vol 231 (2) ◽  
pp. 395-410
Author(s):  
Jaehoon Lee ◽  
Dong-Min Park ◽  
Yonghwan Kim
Keyword(s):  
Model Tests ◽  
Green Water ◽  
Added Resistance ◽  
Hull Form ◽  
Motion Responses ◽  
Wide Range ◽  
Added Resistance In Waves ◽  
Design Speed ◽  
Hull Forms ◽  
Motion Amplitude

The effect of different bow shapes on the added resistance in waves was observed through a series of model tests. To this end, three different hull forms of KRISO Very Large Crude Carrier 2 were considered: an original hull form and two modified hulls with different bow shapes, called ax-bow and leadge-bow. The model tests were conducted for a wide range of wavelengths with two wave amplitudes in a regular head-sea condition at the design speed. Each test condition was imposed at least twice in order to check the repeatability of measurement, considering the uncertainties in model test and the nonlinear nature of the added resistance. This article introduces a preliminary study on the effects of surge motion, amplitude of incident wave, and green-water allowance around bow region. This article briefly includes the uncertainty analysis of recent study regarding the performance of the original hull. Based on the results of the experimental study for three different bow shapes, the parameters which influence the added resistance and motion responses are discussed.

scholarly journals Evaluation of the Effect of Container Ship Characteristics on Added Resistance in Waves

2020 ◽  
Vol 8 (9) ◽  
pp. 696
Author(s):  
Ivana Martić ◽  
Nastia Degiuli ◽  
Andrea Farkas ◽  
Ivan Gospić
Keyword(s):  
Point Of View ◽  
Irregular Waves ◽  
Design Stage ◽  
Radius Of Gyration ◽  
Container Ship ◽  
Added Resistance ◽  
Head Waves ◽  
Calm Water ◽  
Added Resistance In Waves ◽  
Longitudinal Position

Added resistance in waves is one of the main causes of an increase in required power when a ship operates in actual service conditions. The assessment of added resistance in waves is important from both an economic and environmental point of view, owing to increasingly stringent rules set by the International Maritime Organization (IMO) with the aim to reduce CO2 emission by ships. For that reason, it is desirable to evaluate the added resistance in waves already in the preliminary ship design stage both in regular and irregular waves. Ships are traditionally designed and optimized with respect to calm water conditions. Within this research, the effect of prismatic coefficient, longitudinal position of the centre of buoyancy, trim, pitch radius of gyration, and ship speed on added resistance is investigated for the KCS (Kriso Container Ship) container ship in regular head waves and for different sea states. The calculations are performed using the 3D panel method based on Kelvin type Green function. The results for short waves are corrected to adequately take into account the diffraction component. The obtained results provide an insight into the effect of variation of ship characteristics on added resistance in waves.

The Effect of Bow Steepness and Flare on the Resistance of Sailing Yachts in Calm Water and Waves

2001 ◽  
Author(s):  
J. A. Keuning ◽  
R. Onnink ◽  
A. Damman
Keyword(s):  
Water Resistance ◽  
Added Resistance ◽  
University Of Technology ◽  
Head Waves ◽  
Master Thesis ◽  
Calm Water ◽  
Added Resistance In Waves ◽  
Bow Flare ◽  
Sailing Yacht ◽  
Resistance Performance

In this paper some results are presented of two studies carried out at the Ship hydromechanics Department of the Delft University of Technology: one, on the influence of an increase of stem steepness of a sailing yacht, and another, which was largely carried out by T.J.E. Tincelin as part of his master thesis at Delft University of Technology, on the effect of above waterline bow flare are presented. To investigate the influence of bow steepness a model of the Delft Systematic Yacht Hull Series (DSYHS) has been used as a parent model of a new small subseries with two additional derivatives each with increased bow steepness. The influence on both the calm water resistance and the added resistance in head waves has been investigated. To investigate the influence of bow flare, two models of a typical "Open 60" design have been used: one "normal" and one with almost no flare in the bowsections. These have been tested in calm water and in both head- and following­waves to investigate the effects of this difference in bow shape on the calm water resistance, on added resistance in waves, and on the relative motions at the bow. The results are presented and some comparisons with calculations made. Also some general conclusions with respect to resistance, performance and safety are drawn.

A Numerical Study on Correlation Between the Bow Design Parameters and Added Resistance Using the Design of Experiments

2016 ◽  
Author(s):  
Gwan Hoon Kim ◽  
Hyun Joon Shin ◽  
Jeonghwa Seo ◽  
Shin Hyung Rhee
Keyword(s):  
Design Of Experiments ◽  
Numerical Simulations ◽  
Numerical Study ◽  
Design Parameters ◽  
Added Resistance ◽  
Hull Form ◽  
Entrance Angle ◽  
Wave Condition ◽  
Added Resistance In Waves ◽  
Bulbous Bow

In this study, numerical computation was carried out for evaluating the effects of the design parameter variations on the added resistance of Aframax tanker in head seas. The design of experiments (DOE) was used to efficiently conduct the numerical simulations with the hull form variations and save computational resources. A computational fluid dynamics (CFD) code based on the continuity and Reynolds averaged Navier-Stokes (RANS) equation was used for the numerical simulation. The simulation was performed in a short wave condition where the wave length was half of the ship length, which is expected to be most frequent in the vessel operation. Five design parameters of fore-body hull form were selected for the variations: design waterline length (DWL), bulbous bow height (BBH), bulbous bow volume (BBV), bow flare angle (BFA) and bow entrance angle (BEA). Each parameter had two levels in the variations, thus total 32 cases were designed initially. The results of the numerical simulations were analyzed statistically to determine the main effects and correlations in the five design parameters variations. Among them, the most significant parameter that influences on the added resistance in waves was DWL, followed by BBV and BEA. The other parameters had little effects on the added resistance in waves. By the computations, it was revealed that Extending DWL and decreasing BEA promoted the reflection of waves more toward the side than forward. In addition, there existed two-way interactions for the following two-factor combinations: DWL-BFA, DWL-BEA, DWL-BBV, BBH-BBV.

Assessment of Hydrodynamic Tools for R/V Athena Model 5365 in Calm Water

2017 ◽  
Author(s):  
Anne Fullerton ◽  
Charles Weil ◽  
Evan Lee ◽  
Minyee Jiang ◽  
Fredrick Stern ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Structural Design ◽  
High Speed ◽  
Irregular Waves ◽  
Impact Loads ◽  
Empirical Methods ◽  
Regular Waves ◽  
Hull Form ◽  
Calm Water ◽  
Naval Surface Warfare

Current structural design methods for high speed naval craft rely heavily on empirical methods. Though these methods have been employed reliably for a number of years, it is likely that an unknown level of conservatism exists in the prediction of impact loads. A better physical understanding of the dynamic response of high speed craft in seas would allow for increased structural optimization. The publicly releasable hull form Naval Surface Warfare Center Carderock Division (NSWCCD) Model 5365 (R/V Athena) was chosen to facilitate release of results to various computational teams. Model 5365 was tested in calm water, regular waves, and irregular waves. After reviewing data from the first test in 2014, it was determined that the model should be modified to enable towing from the longitudinal center of gravity. Model 5365 was then modified and re-tested using with added calm water speeds, and additional wave conditions. Calm water results from this test are presented with uncertainty analysis for resistance, heave, and trim.

Numerical and Experimental Analysis of Added Resistance of Ships in Waves

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Ould el Moctar ◽  
Sebastian Sigmund ◽  
Jens Ley ◽  
Thomas E. Schellin
Keyword(s):  
Water Resistance ◽  
Frictional Resistance ◽  
Medium Size ◽  
Total Resistance ◽  
Added Resistance ◽  
Short Waves ◽  
Radiation Forces ◽  
Calm Water ◽  
Added Resistance In Waves ◽  
Force Components

Two Reynolds-Averaged Navier–Stokes (RANS) based field methods numerically predicted added resistance in regular head waves for a 14,000 TEU containership and a medium size cruise ship. Long and short waves of different frequencies were considered. Added resistance was decomposed into diffraction and radiation force components, whereby diffraction forces were obtained by restraining the ship in waves and radiation forces by prescribing the motions of the ship in calm water. In short waves, the diffraction part of total resistance was dominant as almost no ship motions were induced. In long waves, the sum of diffraction and radiation forces exceeded total resistance, i.e., the interaction of these two force components, which caused the reduction of total resistance, needed to be accounted for. Predictions were compared with model test measurements. Particular emphasis was placed on the following aspects: discretization errors, frictional resistance as part of total added resistance in waves, and diffraction and radiation components of added resistance in waves. Investigations comprised two steps, namely, a preliminary simulation to determine calm water resistance and a second simulation to compute total resistance in waves, always using the same grids. Added resistance was obtained by subtracting calm water resistance from total averaged wave resistance. When frictional resistance dominated over calm water resistance, which holds for nearly all conventional ships at moderate Froude numbers, high grid densities were required in the neighborhood surrounding the hull as well as prism cells on top of the model's surface.

Numerical and Experimental Analysis of Added Resistance of Ships in Waves

2015 ◽  
Author(s):  
Ould el Moctar ◽  
Sebastian Sigmund ◽  
Thomas E. Schellin
Keyword(s):  
Water Resistance ◽  
Frictional Resistance ◽  
Medium Size ◽  
Total Resistance ◽  
Added Resistance ◽  
Short Waves ◽  
Radiation Forces ◽  
Calm Water ◽  
Added Resistance In Waves ◽  
Force Components

A RANS-based field method numerically predicted added resistance in regular head waves for a 14000 TEU containership (Duisburg Test Case) and a medium-size cruise ship. We concentrated our investigations on short waves. For different frequencies, we decomposed added resistance into diffraction and radiation force components, whereby diffraction forces were obtained by restraining the ship in waves and radiation forces, by prescribing the motions of the ship in calm water. In short waves, the diffraction part of total resistance was dominant as almost no ship motions were induced. In long waves, the sum of diffraction and radiation forces exceeded total resistance, i.e., the interaction of these two force components, which caused the reduction of total resistance, had to be accounted for. Predictions were compared with model test measurements. Particular emphasis was placed on the following aspects: discretization errors, frictional resistance as part of total added resistance in waves, diffraction and radiation components of added resistance in waves, and the influence of surge motion on added resistance. Investigations comprised two steps, namely, a preliminary simulation to determine calm-water resistance and a second simulation to compute total resistance in waves, always using the same grids. Added resistance was obtained by subtracting calm-water resistance from total averaged wave resistance. When frictional resistance dominated calm-water resistance, which holds for nearly all conventional ships at moderate Froude numbers, high grid densities were required in the neighborhood surrounding the hull.

scholarly journals Added Resistance in Waves and Amplitude Function Expressing a Ship Hull Form

2008 ◽  
Vol 8 (0) ◽  
pp. 163-169 ◽  
Author(s):  
Shigeru Naito ◽  
Mariko Kuroda ◽  
Hisahumi Yoshida ◽  
Takehiro Ikeda
Keyword(s):  
Ship Hull ◽  
Added Resistance ◽  
Amplitude Function ◽  
Hull Form ◽  
Added Resistance In Waves

Numerical Prediction of Added Power in Seaway

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Vladimir Shigunov
Keyword(s):  
Performance Monitoring ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Irregular Waves ◽  
Added Resistance ◽  
Engine Model ◽  
Routing Optimization ◽  
Rankine Source ◽  
Calm Water ◽  
Drift Forces

The paper describes a numerical approach to predict required added power for propulsion in waves. Such predictions are important to address fuel consumption in seaway and define suitable operating point and sea margin, as well as for routing optimization and hull performance monitoring. Added resistance and, in general, drift forces and moments due to waves are key input parameters for added power requirements. The three-dimensional Rankine source-patch method was used to compute them. The method solves the problem in the frequency domain, linearizing wave-induced motions around the fully nonlinear steady flow. The added power software combines added resistance and drift forces and moments in irregular waves with wind forces and moments, calm-water maneuvering forces and moments, rudder and propeller forces, and propulsion and engine model and provides associated resistance and power as well as changes in ship propulsion in waves. The approach is demonstrated for a container ship to compare predictions with full-scale data.

scholarly journals Hull form optimization in the conceptual design stage considering operational efficiency in waves

2018 ◽  
Vol 233 (3) ◽  
pp. 745-759 ◽  
Author(s):  
Yoo-Won Jung ◽  
Yonghwan Kim
Keyword(s):  
Optimization Method ◽  
Operational Efficiency ◽  
Hydrodynamic Performance ◽  
Design Stage ◽  
Total Resistance ◽  
Added Resistance ◽  
Slender Body Theory ◽  
Hull Form ◽  
Weather Factor ◽  
Calm Water

This study focuses on the optimization of ship dimensions by considering hydrodynamic performance in waves. In actual seaways, a ship experiences speed loss due to environmental loads by waves and wind. Therefore, along with calm water resistance, speed loss in waves should be considered in the hull form design in order to improve operational efficiency in waves. However, a trade-off may be needed between total resistance on the ship and the speed loss in waves. To address this problem, Non-dominated Sorting Genetic Algorithm II, which is a multi-objective optimization method, is used to minimize the total resistance on a ship in seaways and the speed loss by additional resistance. In the optimization process, added resistance is predicted using a numerical method based on slender-body theory, Maruo’s far-field formulation, and an empirical formula for added resistance in short waves. The speed loss in waves, which can be expressed by a weather factor ( fw), is estimated using power–speed curves. This article introduces some examples of the sensitivity analysis of added resistance and speed loss in waves to the variations of ship dimensions. Finally, the optimization solutions on a Pareto front set are compared to a basis ship in terms of hull form, and the corresponding hydrodynamic performances are evaluated.

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