Computation of Ship-to-Ship Interaction Forces by a 3D Potential Flow Panel Method in Finite Water Depth

2010 ◽  
Author(s):  
Xueqian Zhou ◽  
Serge Sutulo ◽  
C. Guedes Soares
Keyword(s):  
Water Depth ◽  
Potential Flow ◽  
Hydrodynamic Interaction ◽  
Single Layer ◽  
Mirror Image ◽  
Present Contribution ◽  
Interaction Forces ◽  
Sea Bottom ◽  
Close Proximity ◽  
Finite Water Depth

The double-body 3D potential flow code developed earlier for computing hydrodynamic interaction forces and moments acting on the hulls of the ships sailing in close proximity with neighbouring ships or some other obstacles, is extended to the shallow water case. Two methods for accounting for the finite water depth were implemented: use of truncated mirror image series, and distribution of an additional single layer of sources on parts of the seabed beneath the moving hulls. While the first method does only apply to the flat horizontal seabed, the second one can also deal with the arbitrary bathymetry situations. As appropriate choice of the discretization parameters can significantly affect the accuracy and efficiency of the second method, the present contribution focuses on comparative computations aiming at defining reasonable dimensions of the moving panelled area on the sea bottom and maximum admissible size of the bottom panel. As result, conclusions concerning optimal parameters of the additional set of panels are drawn.

Computation of Ship-to-Ship Interaction Forces by a Three-Dimensional Potential-Flow Panel Method in Finite Water Depth

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Xueqian Zhou ◽  
Serge Sutulo ◽  
C. Guedes Soares
Keyword(s):  
Water Depth ◽  
Potential Flow ◽  
Three Dimensional ◽  
Single Layer ◽  
Mirror Image ◽  
Present Contribution ◽  
Interaction Forces ◽  
Sea Bottom ◽  
Close Proximity ◽  
Finite Water Depth

A double-body 3D potential-flow code developed earlier for computing hydrodynamic interaction forces and moments acting on the hulls of the ships sailing in close proximity with neighboring ships or some other obstacles, is extended to the shallow water case. Two methods for accounting for the finite water depth were implemented: (1) using truncated mirror image series and (2) distribution of an additional single layer of sources on parts of the seabed beneath the moving hulls. While the first method does only apply to the flat horizontal seabed, the second one can also deal with the arbitrary bathymetry situations. As appropriate choice of the discretization parameters can significantly affect the accuracy and efficiency of the second method, the present contribution focuses on comparative computations aiming at defining reasonable dimensions of the moving paneled area on the sea bottom and maximum admissible size of the bottom panel. As result, conclusions concerning optimal parameters of the additional set of panels are drawn.

Maneuvering Simulation of Two Ships During Meeting and Passing

2014 ◽  
Vol 69 (7) ◽  
Author(s):  
Koki Kitagawa ◽  
Masaaki Sano ◽  
Hironori Yasukawa
Keyword(s):  
Water Depth ◽  
Panel Method ◽  
Time Step ◽  
Interaction Forces ◽  
Motion Equations ◽  
Close Proximity ◽  
External Forces ◽  
Ship Speed

Motion equations of two ships maneuvering in close proximity are solved in consideration of the interaction between hulls. The interaction forces are calculated by a 3D panel method as a function of the ship position in the time step and considered as external forces in maneuvering. Four kinds of ships are prepared and the maneuvering motions are simulated with variation of the combination of ships, water depth, ship speed and draft. The effect of those parameters on the interaction forces and two ships behaviors are investigated. 

Hydrodynamic Interaction Forces on Ship Hulls Equipped With Propulsors

2012 ◽  
Author(s):  
Serge Sutulo ◽  
C. Guedes Soares
Keyword(s):  
Pressure Distribution ◽  
Hydrodynamic Interaction ◽  
Potential Interaction ◽  
Interaction Forces ◽  
Ship Hulls ◽  
Actuator Disk ◽  
Close Proximity ◽  
Body Potential ◽  
Yaw Moment ◽  
Accelerating Motion

Typically, study of hydrodynamic interaction between vessels navigating in close proximity to each other is limited to hydrodynamics of bare hulls. Meanwhile, ship propulsors, especially heavily loaded, which may happen in accelerating motion, can alter substantially the flow and distribution of pressure on the hulls which can be viewed as generalization of the thrust deduction phenomenon. The 3D doubled body potential interaction code based on the source panel method developed earlier by the authors has been enhanced to include the effect of a propeller on each of the interacting ships under the assumption that the propeller jets (slipstreams) are not involved into the interaction. Each propeller is simulated by a disk of sinks further approximated with a polygon composed of identical triangular panels with identical constant sink density linked to the thrust of the propulsor according to the actuator disk theory. Comparative computations were carried out for two identical tanker vessels in the close-proximity overtaking manoeuvre at various values of the loading coefficient of each propeller. The loading coefficient is not supposed to be necessarily defined by the steady propulsion point. Numerical results demonstrate that a heavily loaded propeller substantially modifies the pressure distribution on both hulls resulting in alteration of the hydrodynamic interaction loads, especially of the surge force and yaw moment.

SHIP-SHIP HYDRODYNAMIC INTERACTION IN CONFINED WATERS WITH COMPLEX BOUNDARIES BY A PANELLED MOVING PATCH METHOD

2021 ◽  
Vol 158 (A1) ◽  
Author(s):  
X-Q Zhou ◽  
S Sutulo ◽  
C Guedes Soares
Keyword(s):  
Shallow Water ◽  
Satisfactory Agreement ◽  
Potential Flow ◽  
Hydrodynamic Interaction ◽  
Mirror Image ◽  
Ship Hulls ◽  
Seabed Topography ◽  
Image Technique ◽  
Ship Hydrodynamic ◽  
Complex Boundaries

This paper presents a potential flow solution for online estimation of hydrodynamic interaction between ships moving in restricted waters with complex boundaries. Each ship in concern is linked with a moving patch representing the arbitrary bathymetry beneath it. The wetted surfaces of ship hulls are meshed and loaded prior to the simulation, while the moving patches are dynamically discretized by a fast and robust mesh generator. The proposed method is validated for the ship- ship interaction case in the shallow water case with a flat and horizontal seabed where the mirror image technique is applicable, and satisfactory agreement is obtained. The method is further applied to simulate two interaction scenarios involving arbitrary seabed topography, and the numerical results are obtained and discussed.

A Numerical Method for Calculation of Ship–Ship Hydrodynamics Interaction in Shallow Water Accounting for Sinkage and Trim

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Huilong Ren ◽  
Chen Xu ◽  
Xueqian Zhou ◽  
Serge Sutulo ◽  
Carlos Guedes Soares
Keyword(s):  
Shallow Water ◽  
Hydrodynamic Interaction ◽  
Mirror Image ◽  
Image Method ◽  
Interaction Forces ◽  
Ship Hydrodynamics ◽  
Time Simulation ◽  
Water Accounting ◽  
Ship Hydrodynamic ◽  
Sinkage And Trim

Abstract Sinkage and trim, which often occur to ships moving in shallow water, do not only have an effect on the ship–ship hydrodynamic interaction forces but also increase the risk of grounding. Potential flow-based online calculation of ship–ship hydrodynamic interaction forces without accounting for dynamic sinkage and trim is able to capture the hydrodynamic interaction effects with fair accuracy; however, there are still discrepancies in many cases, especially in the case of shallow water. An algorithm based on the potential theory has been devised for real-time simulation of the hydrodynamic interaction between two ships in shallow water accounting for sinkage and trim. The shallow water condition is modeled using the mirror image method. The sinkage and trim are solved iteratively based on the principle of hydrodynamic balance, where a mesh trimming procedure is carried out when the waterline is changed. Simulations are performed with and without accounting for the sinkage and trim, and comparison with experimental results shows a fair agreement.

Simulation of the Hydrodynamic Interaction Forces in Close-Proximity Manoeuvring

2008 ◽  
Author(s):  
Serge Sutulo ◽  
C. Guedes Soares
Keyword(s):  
Real Time ◽  
Hydrodynamic Interaction ◽  
Moving Objects ◽  
Time Derivative ◽  
Kirchhoff Equations ◽  
Interaction Forces ◽  
Acceptable Accuracy ◽  
Close Proximity ◽  
Added Masses ◽  
Real Time Simulations

A code for simulating hydrodynamic interaction forces in manoeuvring simulating systems has been created. The algorithm takes into account potential forces only and is based on the Hess and Smith panel method. Own inertial hydrodynamic forces were estimated through pre-calculation of the added masses followed by use of the Thomson–Tait–Kirchhoff equations. Comparative computations of the added masses, surge and sway interaction forces and yaw interaction moments with varying number of surface computational panels showed that on a typical modern PC, an acceptable accuracy in terms of the integrated loads can be reached with a relatively small number of panels permitting real-time simulations with the developed algorithm in the loop. Importance of the account for the local time derivative of the potential has been demonstrated on comparative calculations in simulation of a passing-by manoeuvre. The code can be used for predicting interaction loads with any number of moving objects and fixed obstacles.

A Numerical Method for Calculation of Ship-Ship Hydrodynamics Interaction in Shallow Water Accounting for Sinkage and Trim

2019 ◽  
Author(s):  
Huilong Ren ◽  
Chen Xu ◽  
Xueqian Zhou ◽  
Serge Sutulo ◽  
Carlos Guedes Soares
Keyword(s):  
Shallow Water ◽  
Hydrodynamic Interaction ◽  
Mirror Image ◽  
Image Method ◽  
Interaction Forces ◽  
Time Simulation ◽  
Water Accounting ◽  
Ship Hydrodynamic ◽  
Sinkage And Trim ◽  
Hydrostatic Balance

Abstract Sinkage and trim, which often occur to ships moving in shallow water, do not only have an effect on the ship-ship hydrodynamic interaction forces, but also increase the risk of grounding. An algorithm based on the potential theory has been devised for real-time simulation of the hydrodynamic interaction between two ships in shallow water accounting for sinkage and trim. The shallow water condition is modeled using the mirror image method; while the sinkage and trim are solved iteratively based on the principle of hydrostatic balance, where a mesh trimming procedure is performed when the waterline is changed. Simulations are performed with and without accounting for the sinkage and trim, and comparison with experimental results shows a fair agreement.

Sign in / Sign up

Export Citation Format

Share Document