New Progress of Ship’s Increment Resistance in Waves

2013 ◽  
Vol 787 ◽  
pp. 538-541
Author(s):  
Jian Fei Zhao ◽  
Fu Jun Zhao
Keyword(s):  
Experimental Study ◽  
Green Function ◽  
Theoretical Prediction ◽  
Present State ◽  
Research Development ◽  
Added Resistance ◽  
Traditional Methods ◽  
Added Resistance In Waves

Starting with the physics nature of ships added resistance in waves, this paper mainly expounds the research development and present state in this field from theoretical prediction, experimental study and frontier of the added resistance. It seems that CFD and 3-D Green function are more applicable for solving the added resistance problem than traditional methods.

Added Resistance in Seaways and its Impact on Yacht Performance

2007 ◽  
Author(s):  
Kai Graf ◽  
Marcus Pelz ◽  
Volker Bertram ◽  
H. Söding
Keyword(s):  
Strong Impact ◽  
Wave Spectra ◽  
Linear Extensions ◽  
Added Resistance ◽  
Optimum Length ◽  
Prediction Program ◽  
Strip Theory ◽  
Velocity Prediction ◽  
Added Resistance In Waves ◽  
Response Amplitude Operators

A method for the prediction of seakeeping behaviour of sailing yachts has been developed. It is based on linear strip theory with some non-linear extensions. The method is capable to take into account heeling and yawing yacht hulls, yacht appendages and sails. The yacht's response amplitude operators (RAO) and added resistance in waves can be predicted for harmonic waves as well as for natural wave spectra. The method is used to study added resistance in seaways for ACC-V5 yachts of varying beam. Results are used for further VPP investigations. The AVPP velocity prediction program is used to study optimum length to beam ratio of the yachts depending on wind velocity and upwind to downwind weighting. This investigation is carried out for flat water conditions as well as for two typical wave spectra. The results show that taking into account added resistance in seaways has a strong impact on predicted performance of the yacht.

SHIP MOTIONS DURING REPLENISHMENT AT SEA OPERATIONS IN HEAD SEAS

2021 ◽  
Vol 152 (A4) ◽  
Author(s):  
G Thomas ◽  
T Turner ◽  
T Andrewartha ◽  
B Morris
Keyword(s):  
Experimental Study ◽  
Green Function ◽  
Prediction Method ◽  
Ship Motion ◽  
Motion Prediction ◽  
Ship Motions ◽  
Forward Speed ◽  
Theoretical Predictions ◽  
Relative Separation ◽  
Replenishment At Sea

During replenishment at sea operations the interaction between the two vessels travelling side by side can cause significant motions in the smaller vessel and affect the relative separation between their replenishment points. A study into these motions has been conducted including theoretical predictions and model experiments. The model tests investigated the influence of supply ship displacement and longitudinal separation on the ships’ motions. The data obtained from the experimental study has been used to validate a theoretical ship motion prediction method based on a 3-D zero-speed Green function with a forward speed correction in the frequency domain. The results were also used to estimate the expected extreme roll angle of the receiving vessel, and the relative motion between the vessels, during replenishment at sea operations in a typical irregular seaway. A significant increase in the frigate’s roll response was found to occur with an increase of the supply ship displacement, whilst a reduction in motion for the receiving vessel resulted from an increase in longitudinal separation between the vessels. It is proposed that to determine the optimal vessel separation it is vital that the motions of the vessels are not considered in isolation and all motions need to be considered for both vessels simultaneously.

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.

Numerical Analysis on Added Resistance of Ship by 3-D Green Function Method

2006 ◽  
Author(s):  
Yoshiyuki Inoue ◽  
N. M. Golam Zakaria
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Green Function ◽  
Function Method ◽  
Numerical Results ◽  
Numerical Code ◽  
Added Resistance ◽  
Green Function Method ◽  
Total Potential ◽  
Motion Responses

This paper deals with the numerical analysis on added resistance of a ship by 3-D Green Function Method. Linear potential theory has been used to describe the fluid motion and 3-D sink-source technique with forward speed has been applied to determine hydrodynamic forces for surface ship advancing in waves at constant speed. After solving the motion equation in frequency domain, radiation potential due to motion responses have been calculated to obtain the total potential of the flow field. Then, total potential and its derivatives have been obtained to assess the added resistance in waves by near field approach. To show the validity of the numerical code, the present numerical results for motion responses and wave loads on ships have been compared with experimental data as well as some numerical results by different approaches. Then the added resistances given by present numerical calculation by 3-D Green Function have been compared with some classical 2-D methods as well as experimental data for Series 60 ships. Finally the present numerical calculations have been applied for fuller form slow speed vessel where the classical 2-D methods usually fails to give good results due to their inherent limitations. The numerical results suggest that better agreement have been achieved in many cases using present full 3-D Green Function method.

scholarly journals Theoretical prediction and experimental study of a ferromagnetic shape memory alloy:Ga2MnNi

2008 ◽  
Vol 78 (13) ◽  
Author(s):  
S. R. Barman ◽  
Aparna Chakrabarti ◽  
Sanjay Singh ◽  
S. Banik ◽  
S. Bhardwaj ◽  
...  
Keyword(s):  
Experimental Study ◽  
Theoretical Prediction ◽  
Shape Memory ◽  
Ferromagnetic Shape Memory
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