Hydrodynamic Interaction Between Two Ships Arranged Side by Side in Shallow Water

2014 ◽  
Author(s):  
Zhiming Yuan ◽  
Atilla Incecik ◽  
Shi He
Keyword(s):  
Shallow Water ◽  
Hydrodynamic Interaction ◽  
Wave Pattern ◽  
Present Calculation ◽  
Water Effect ◽  
Green Function Method ◽  
Rankine Source ◽  
The Mean ◽  
Shallow Water Effect ◽  
Good Agreement

The hydrodynamic interaction between two ships with side-by-side arrangement is analyzed by using 3-D Rankine source panel code. The source points are distributed over the mean wetted body surface as well as on the free surface. The shallow water effect has been taken into consideration. Moreover, the influence of the distance between the vessels is also investigated. To verify the present code, two Wigley III hulls are simulated both in beam sea and head sea conditions. The wave pattern and the motion RAOs of 6-DOF are calculated by present code and compared with WADAM program which is based on Green function method. From the comparisons, good agreement is found between present calculation and Wadam results. It is found that the hydrodynamic interactions are generally important especially in beam sea case. The resonant frequency is greatly influenced by the distance between the vessels.

Experimental Investigation of Trimaran Models in Shallow Water

2014 ◽  
Vol 30 (02) ◽  
pp. 66-78
Author(s):  
Mark Pavkov ◽  
Morabito Morabitob
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Critical Speed ◽  
Water Effect ◽  
Finite Water Depth ◽  
Speed Regime ◽  
Displacement Speed ◽  
Littoral Combat Ship ◽  
Shallow Water Effect ◽  
The U.S

Experiments were conducted at the U.S. Naval Academy's Hydromechanics Laboratory to determine the effect of finite water depth on the resistance, heave, and trim of two different trimaran models. The models were tested at the same length to water depth ratios over a range of Froude numbers in the displacement speed regime. The models were also towed in deep water for comparison. Additionally, the side hulls were adjusted to two different longitudinal positions to investigate possible differences resulting from position. Near critical speed, a large increase in resistance and sinkage was observed, consistent with observations of conventional displacement hulls. The data from the two models are scaled up to a notional 125-m length to illustrate the effects that would be observed for actual ships similar in size to the U.S. Navy's Independence Class Littoral Combat Ship. Faired plots are developed to allow for rapid estimation of shallow water effect on trimaran resistance and under keel clearance. An example is provided.

scholarly journals A Fast Algorithm for the Prediction of Ship-Bank Interaction in Shallow Water

2020 ◽  
Vol 8 (11) ◽  
pp. 927
Author(s):  
Jin Huang ◽  
Chen Xu ◽  
Ping Xin ◽  
Xueqian Zhou ◽  
Serge Sutulo ◽  
...  
Keyword(s):  
Shallow Water ◽  
Hydrodynamic Interaction ◽  
Surface Boundary ◽  
Complex Flow ◽  
Ship Maneuvering ◽  
Interaction Forces ◽  
Rankine Source ◽  
Bank Effect ◽  
Sinkage And Trim ◽  
Navigation Safety

The hydrodynamic interaction induced by the complex flow around a ship maneuvering in restricted waters has a significant influence on navigation safety. In particular, when a ship moves in the vicinity of a bank, the hydrodynamic interaction forces caused by the bank effect can significantly affect the ship’s maneuverability. An efficient algorithm integrated in onboard systems or simulators for capturing the bank effect with fair accuracy would benefit navigation safety. In this study, an algorithm based on the potential-flow theory is presented for efficient calculation of ship-bank hydrodynamic interaction forces. Under the low Froude number assumption, the free surface boundary condition is approximated using the double-body model. A layer of sources is dynamically distributed on part of the seabed and bank in the vicinity of the ship to model the boundary conditions. The sinkage and trim are iteratively solved via hydrostatic balance, and the importance of including sinkage and trim is investigated. To validate the numerical method, a series of simulations with various configurations are carried out, and the results are compared with experiment and numerical results obtained with RANSE-based and Rankine source methods. The comparison and analysis show the accuracy of the method proposed in this paper satisfactory except for extreme shallow water cases.

scholarly journals Confirmation of shallow water effect in swimming pool

2004 ◽  
Vol 7 (1) ◽  
pp. 59-65
Author(s):  
Tokuzo FUKAMACHI ◽  
Tetsuo KAWASE ◽  
Yoshiaki TSUKADA
Keyword(s):  
Shallow Water ◽  
Swimming Pool ◽  
Water Effect ◽  
Shallow Water Effect

scholarly journals Ship-to-Ship Interaction during Overtaking Operation in Shallow Water

2015 ◽  
Vol 59 (03) ◽  
pp. 172-187
Author(s):  
Zhi-Ming Yuan ◽  
Paula Kellet ◽  
Atilla Incecik ◽  
Osman Turan ◽  
Evangelos Boulougouris
Keyword(s):  
Shallow Water ◽  
Hydrodynamic Interaction ◽  
Contributory Factor ◽  
Test Results ◽  
Loss Of Life ◽  
Narrow Channels ◽  
Rankine Source ◽  
Wave Patterns ◽  
Computational Fluid Dynamics Cfd ◽  
Numerical Program

Hydrodynamic interaction continues to be a major contributory factor in marine casualties and hazardous incidents, in particular, in the case of overtaking operations. The situation becomes even worse when the overtaking operation occurs in shallow and narrow channels, where the interaction can cause the vessels to collide and, in one case has caused the capsizal of the smaller vessel with loss of life. The aim of this article is to propose a methodology, as well as to discuss the development of a numerical program, to predict the ship-to-ship interaction during overtaking operations in shallow water. Since the vessels involved in this study have different forward speeds, an uncoupled method will be used to solve the boundary value problem. The in-house multibody hydrodynamic interaction program MHydro, which is based on the 3D Rankine source method, is used and extended here to investigate the interactive forces and wave patterns between two ships during an overtaking operation. The calculations given in this article are compared with model test results as well as published computational fluid dynamics (CFD) calculations. Very satisfactory agreement has been obtained, which indicates that the proposed methodology and developed program are successfully validated to predict the hydrodynamic interaction between two ships advancing in confined waters. The discussions also highlight the speed effects.

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