Numerical Investigation on the Influence of Froude Number on the Hydrodynamic Derivatives of a Container Ship

2016 ◽  
Author(s):  
Rameesha Thayale Veedu ◽  
Parameswaran Krishnankutty
Keyword(s):  
Hydrodynamic Characteristics ◽  
Container Ship ◽  
Trajectory Prediction ◽  
Ship Maneuvering ◽  
Approach Speed ◽  
Hydrodynamic Derivatives ◽  
Planar Motion Mechanism ◽  
Early Design Stages ◽  
Derivatives Of ◽  
Vessel Speed

Evaluation of maneuverability of a ship at the early design stages is necessary for ensuring safety of its voyage. IMO recommends the test speed or approach speed for the maneuvering predictions as 90–100% of the service speed of the vessel. The confined model tests for ship maneuvering assessment are usually conducted at low speeds and the hydrodynamic derivatives obtained from these tests are used in the equation of motion even when vessel operates at much higher speeds. But the hydrodynamic derivatives and consequently the trajectory predicted using these derivatives differ substantially from the actual maneuvering conditions. Hence the dependency of the derivatives on vessel speed needs to be understood properly to get the correct estimate of the vessel trajectory prediction. This paper investigates the effect of vessel speed (Fn) on hydrodynamic characteristics of a container ship. Straightline test and horizontal planar motion mechanism (HPMM) tests are conducted for a container ship model for different speeds in a CFD environment.

Numerical Study on the Maneuvering of a Ship in Waves Based on Unified State Space Model

2016 ◽  
Author(s):  
Rameesha Thayale Veedu ◽  
Parameswaran Krishnankutty
Keyword(s):  
State Space ◽  
Numerical Study ◽  
State Space Model ◽  
Container Ship ◽  
Regular Waves ◽  
Ship Maneuvering ◽  
Space Model ◽  
Water Conditions ◽  
Calm Water ◽  
Early Design Stages

Ship maneuvering performance is usually predicted in calm water conditions, which provide valuable information about ship’s turning ability and its directional stability in the early design stages. Investigation of maneuvering simulation in waves is more realistic since the ship usually sails through waves. So it is important to study the effect of waves on the turning ability of a ship. This paper presents the maneuvering simulation for a container ship in presence of regular waves based on unified state space model for ship maneuvering. Standard maneuvers like turning circle and zigzag maneuver are simulated for the head sea condition and the same are compared with calm water maneuvers. The present study shows that wave significantly affects the maneuvering characteristics of the ship and hence cannot be neglected.

scholarly journals Numerical Estimation of Hull Hydrodynamic Derivatives in Ship Maneuvering Prediction

2021 ◽  
Vol 28 (2) ◽  
pp. 46-53
Author(s):  
Radosław Kołodziej ◽  
Paweł Hoffmann
Keyword(s):  
Model Tests ◽  
Circular Motion ◽  
Computational Method ◽  
Design Stage ◽  
Hydrodynamic Characteristics ◽  
Ship Maneuvering ◽  
Hydrodynamic Derivatives ◽  
Captive Model Tests ◽  
Ship Maneuverability ◽  
Free Running

Abstract Prediction of the maneuvering characteristics of a ship at the design stage can be done by means of model tests, computational simulations or a combination of both. The model tests can be realized as a direct simulation of the standard maneuvers with the free running model, which gives the most accurate results but is also the least affordable, as it requires a very large tank or natural lake, as well as the complex equipment of the model. Alternatively, a captive model test can be used to identify the hydrodynamic characteristics of the hull, which can be used to simulate the standard maneuvers with the use of dedicated software. Two types of captive model tests are distinguished: circular motion tests (CMT) and planar motion mechanism tests (PMM). The paper presents an attempt to develop a computational method for ship maneuverability prediction in which the hydrodynamic characteristics of the hull are identified by means of computational fluid dynamics (CFD). The CFD analyses presented here directly simulate the circular motion test. The resulting hull characteristics are verified against the available literature data, and the results of the simulations are verified against the results of free running model tests. Reasonable agreement shows the large potential of the proposed method.

Numerical Prediction of Ship Hydrodynamic Derivatives in Close Proximity to a Vertical Bank and Maneuvering Stability Analysis

2016 ◽  
Author(s):  
Han Liu ◽  
Ning Ma ◽  
Xiechong Gu
Keyword(s):  
Lateral Force ◽  
Ship Maneuvering ◽  
Directional Stability ◽  
Bank Effect ◽  
Hydrodynamic Derivatives ◽  
Captive Model Tests ◽  
Close Proximity ◽  
Derivatives Of ◽  
Yaw Moment ◽  
Water Depths

As bank effect has a remarkable influence on the maneuverability of a ship proceeding close to a vertical bank, the assessment of ship maneuvering stability is of great importance. The hydrodynamic derivatives of a ship can reflect the change of the ship’s maneuverability and they are determined with the method of planar motion mechanism (PMM) tests. This paper presents a numerical way to simulate the PMM captive model tests for the ship KVLCC2. A general purpose viscous flow solver was adopted to solve unsteady Reynolds averaged Navier Stokes (RANS) equations in conjunction with a RNG k-ε turbulence model. A hybrid dynamic mesh technique is developed to update the mesh volume around the ship hull when the ship is undertaking pure yaw motions and it turns out efficient and effective to solve the limitation of small ship-bank distance to the mesh configuration and remeshing.. The numerical simulations and the accuracy of the numerical method was validated in comparison with the results of PMM tests in a circulating water channel. Then a series of distances between ship and bank together with different water depths were set for simulating the PMM tests of the KVLCC2 model in proximity to a vertical bank. The first order hydrodynamic derivatives of the ship were analyzed from the time history of lateral force and yaw moment according to the multiple-run simulating procedure. The values of derivatives in different lateral proximities to the bank and variant water depths were compared and it showed some favorable trends for predicting the ship’s maneuverability in the restricted waterways. For example, the influence of velocity derivatives on lateral force reduces while that of velocity derivatives on yaw moment strengthens and this is partly due to the suction force and bow-out moment caused by bank wall effect. The straight line stability and directional stability in terms of the calculated hydrodynamic derivatives were also discussed based on the MMG model for ship maneuvering. Results indicate that the ship is inherently unstable without control and the enhancement of bank effect makes the condition even worse. Moreover, a stable or unstable zone of PD controller parameters focusing on the directional stability was illustrated and setting the values of controller parameters in the range of “Control with high sensitivity” is recommended for cases of the ship navigating in very close proximity to a bank.

Ship-Bank Interaction of a Large Tanker and Related Control Problems

2013 ◽  
Author(s):  
Philipp Mucha ◽  
Ould el Moctar
Keyword(s):  
Control Theory ◽  
Vertical Wall ◽  
Planar Motion ◽  
Navier Stokes ◽  
Linear Quadratic ◽  
Ship Maneuvering ◽  
Motion Mechanism ◽  
Hydrodynamic Derivatives ◽  
Planar Motion Mechanism ◽  
And Control

The objective of this work is to establish a synthesis between modern methodology in the field of ship maneuvering and control theory using the example of hydrodynamic ship-bank interactions for a large tanker. Evolving technologies have paved the way for developing increasingly sophisticated modeling techniques to study ship flows. These tecnologies have made it possible to resemble Planar Motion Mechanism (PMM) tests in numerical simulations using Reynolds-averaged Navier-Stokes (RANS) equations. These advances give way for the numerical determination of hydrodynamic derivatives as present in the maneuvering equations. This methodology is adopted in the present investigation to obtain these coefficients for various separation distances to a vertical wall. Likewise, control theory has experienced vital progress enabling engineers to apply elaborate control policies in their systems. Special attention has been payed to the distinct discipline of optimal control theory and the family of Linear Quadratic (LQ) regulators. Among the popular class of conventional Proportional-Integral-Derivative (PID) controllers rather heuristic design procedures are applied; appealing to the practitioners but might not be suitable for special applications. The work presented investigates the suitablity of deriving hydrod-namic properties by means of Virtual Planar Motion Mechanism (VPMM) tests for the KVLCC2 tanker travelling at various distances to a vertical wall of infinite depth. In subsequent maneuvering simulations the performance of the introduced controllers is discussed.

scholarly journals Preliminary Study of Ship Maneuvering Prediction of Container Ship

2021 ◽  
Vol 1052 (1) ◽  
pp. 012001
Author(s):  
A N Yulianto ◽  
W D Aryawan ◽  
T Putranto ◽  
S H Sujiatanti ◽  
G M Ahadyanti ◽  
...  
Keyword(s):  
Container Ship ◽  
Ship Maneuvering ◽  
Preliminary Study

scholarly journals The Simulation of Sloped Bank Effect Influence on Container Ship Trajectory

2021 ◽  
Vol 9 (11) ◽  
pp. 1283
Author(s):  
Mate Baric ◽  
Robert Mohovic ◽  
Djani Mohovic ◽  
Vinko Pavic
Keyword(s):  
Traffic Flow ◽  
Significant Influence ◽  
Suez Canal ◽  
Container Ship ◽  
Design Standards ◽  
Bank Effect ◽  
Flow Through ◽  
External Forces ◽  
The Impact ◽  
Vessel Speed

The latest container vessel grounding in the Suez Canal, which occurred on 23 March 2021 (the Ever Given), raised many questions regarding the safety of navigation. The sudden concern about safety is due to fears that traffic flow through the Suez Canal could be blocked for longer periods of time. Besides external forces imposed by wind, in this case bank effect had a significant influence on the ship’s grounding. Bank effect occurs due to restricted water flow caused by narrow waterways. Many fairway design standards consider sloped banks such as those of the Suez Canal as unsubstantial in bank-effect forces. This paper analyses the impact of sloped banks on container ship trajectory and proposes minimal distances that may decrease bank-effect forces in order to reduce the risk of vessel grounding and increase the safety of navigation. However, this type of accident has happened before and may occur again due to a small sailing distance from the bank in cases where vessel speed is increased.

scholarly journals Estimation of Hydrodynamic Derivatives of Submarine Model by Using VPMM Test

2014 ◽  
Vol 38 (2) ◽  
pp. 97-103 ◽  
Author(s):  
Jin-Woo Jung ◽  
Jae-Hun Jeong ◽  
In-Gyu Kim ◽  
Seung-Keon Lee
Keyword(s):  
Hydrodynamic Derivatives ◽  
Derivatives Of
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