Numerical investigation on the influence of Froude number on the maneuvering characteristics of a container ship
About: This article is published in International shipbuilding progress.The article was published on 2018-01-01. It has received 1 citations till now. The article focuses on the topics: Froude number & Container (abstract data type).
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TL;DR: Oceanographic research vessels (ORVs) are used to collect ocean data and analyse them to understand the physical, chemical and biological characteristics of seawater, seabed and other ocean-related...
Abstract: Oceanographic research vessels (ORVs) are used to collect ocean data and analyse them to understand the physical, chemical and biological characteristics of seawater, seabed and other ocean-related...
2 citations
Cites background from "Numerical investigation on the infl..."
...Rameesha and Krishnankutty (2018) studied variation in hydrodynamic derivatives with Froude number for s175 container....
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TL;DR: In this paper, two new two-equation eddy-viscosity turbulence models are presented, which combine different elements of existing models that are considered superior to their alternatives.
Abstract: Two new two-equation eddy-viscosity turbulence models will be presented. They combine different elements of existing models that are considered superior to their alternatives. The first model, referred to as the baseline (BSL) model, utilizes the original k-ω model of Wilcox in the inner region of the boundary layer and switches to the standard k-e model in the outer region and in free shear flows. It has a performance similar to the Wilcox model, but avoids that model's strong freestream sensitivity
15,459 citations
TL;DR: In this article, the MMG standard method is introduced, which is composed of four elements; maneuvering simulation model, procedure of the required captive model tests to capture the hydrodynamic force characteristics, analysis method for determining the hydrogravitational force coefficients for maneuvering simulations, and prediction method for the maneuvering motions of a ship in fullscale.
Abstract: A lot of simulation methods based on Maneuvering Modeling Group (MMG) model for ship maneuvering have been presented. Many simulation methods sometimes harm the adaptability of hydrodynamic force data for the maneuvering simulations since one method may be not applicable to other method in general. To avoid this, basic part of the method should be common. Under such a background, research committee on “standardization of mathematical model for ship maneuvering predictions” was organized by the Japan Society of Naval Architects and Ocean Engineers and proposed a prototype of maneuvering prediction method for ships, called “MMG standard method”. In this article, the MMG standard method is introduced. The MMG standard method is composed of 4 elements; maneuvering simulation model, procedure of the required captive model tests to capture the hydrodynamic force characteristics, analysis method for determining the hydrodynamic force coefficients for maneuvering simulations, and prediction method for maneuvering motions of a ship in fullscale. KVLCC2 tanker is selected as a sample ship and the captive mode test results are presented with a process of the data analysis. Using the hydrodynamic force coefficients presented, maneuvering simulations are carried out for KVLCC2 model and the fullscale ship for validation of the method. The present method can roughly capture the maneuvering motions and is useful for the maneuvering predictions in fullscale.
331 citations
TL;DR: In this paper, the yaw-sway-roll-rudder coupling can be a cause of anomalous rolling which is frequently observed at automatically steered, high speed operations in seaways.
Abstract: Digital simulation of maneuvering motions and numerical calculation of directional stability indices are carried out on the basis of captive model test of a typical container ship. An emphasis is laid upon yaw-sway-roll-rudder coupled motion. The smaller metacenteric height proved to introduce the better turning performance and the poorer course-keeping characteristics.The yaw-sway-roll-rudder coupling can be a cause of anomalous rolling which is frequently observed at automatically steered, high speed operations in seaways. We introduce a perturbation stability analysis on the problem. It reveals the possibility of an unstable yaw-roll behavior due to roll-induced yaw moment, small GM and inadequate control parameters of autopilot steering system.
133 citations
TL;DR: The SIMMAN 2008 workshop as discussed by the authors benchmarked the prediction capabilities of different ship maneuvering simulation methods including systems- and CFD-based methods through systematic quantitative comparisons and validation against EFD data for tanker (KVLCC), container ship (KCS), and surface combatant (5415) hull form test cases.
Abstract: The SIMMAN 2008 workshop was held in Copenhagen, Denmark in April 2008. The purpose of the workshop was to benchmark the prediction capabilities of different ship maneuvering simulation methods including systems- and CFD-based methods through systematic quantitative comparisons and validation against EFD data for tanker (KVLCC), container ship (KCS), and surface combatant (5415) hull form test cases. For the KVLCC test case, two stern shape variants named KVLCC1 and KVLCC2 giving different instability loops were included. Free model test data was compared with systems-based methods and CFD for specified free maneuvers. Some of the systems-based methods used provided PMM and CMT data, and two used CFD instead. CFD-based methods were used to simulate forced motions and were compared with PMM/CMT model test data. The submissions were blind in the sense that the benchmark model test data was not provided prior to the workshop, unless data was required as input to the simulation method. A total of 64 submissions were received for the free maneuver simulations, which included a wide range of the state-of-the-art methods in use today, such as PMM- and CMT-based methods, CFD-based methods, system identification, neural network tools and various empirical methods. For the forced motion simulations a total of 16 submissions were received, comprising different CFD-based methods such as RANS, URANS, and DES. This paper gives an overview of hulls, model tests, test cases, submissions, comparison results as well as the most important observations and conclusions.
123 citations
TL;DR: In this article, the URANS computations of standard maneuvers are performed for a surface combatant at model and full scale using CFDShip-Iowa v4, a free surface solver designed for 6DOF motions in free and semi-captive problems.
Abstract: Unsteady Reynolds averaged Navier–Stokes (URANS) computations of standard maneuvers are performed for a surface combatant at model and full scale. The computations are performed using CFDShip-Iowa v4, a free surface solver designed for 6DOF motions in free and semi-captive problems. Overset grids and a hierarchy of bodies allow the deflection of the rudders while the ship undergoes 6DOF motions. Two types of maneuvers are simulated: steady turn and zigzag. Simulations of steady turn at 35° rudder deflection and zigzag 20/20 maneuvers for Fr = 0.25 and 0.41 using constant RPM propulsion are benchmarked against experimental time histories of yaw, yaw rate and roll, and trajectories, and also compared against available integral variables. Differences between CFD and experiments are mostly within 10 % for both maneuvers, highly satisfactory given the degree of complexity of these computations. Simulations are performed also with waves, and with propulsion at either constant RPM or torque. 20/20 zigzag maneuvers are simulated at model and full scale for Fr = 0.41. The full scale case produces a thinner boundary layer profile compared to the model scale with different reaction times and handling needed for maneuvering. Results indicate that URANS computations of maneuvers are feasible, though issues regarding adequate modeling of propellers remain to be solved.
113 citations