scholarly journals Horizontal Planar Motion Mechanism (HPMM) Incorporated to the existing towing carriage for Ship Manoeuvring Studies

2017 ◽  
Author(s):  
Akhil Balagopalan ◽  
Kunal Tiwari ◽  
P. Krishnankutty
Keyword(s):  
Equations Of Motion ◽  
Experimental Studies ◽  
Planar Motion ◽  
Modes Of Operation ◽  
Motion Mechanism ◽  
Towing Tank ◽  
Ship Model ◽  
Ship Manoeuvring ◽  
Hydrodynamic Derivatives ◽  
Planar Motion Mechanism

Planar Motion Mechanism (PMM) equipment is a facility generally attached with Towing Tank to perform experimental studies with ship models to determine the manoeuvring characteristics of a ship. Ship model is oscillated at prescribed amplitude and frequency in different modes of operation while it is towed along the towing tank at predefined speed.The hydrodynamic forces and moments are recorded, analyzed and processed to get the hydrodynamic derivatives appearing in the manoeuvring equations of motion of a ship. This paper presents the details about the Horizontal Planar Motion Mechanism (HPMM) equipment which is designed, developed and installed in Towing Tank laboratory at IIT Madras.

Benchmark Study and Uncertainty Assessment of Planar Motion Mechanism Tests on KVLCC2 in a Circulating Water Channel

2021 ◽  
Author(s):  
Chengqian Ma ◽  
Ning Ma ◽  
Xiechong Gu
Keyword(s):  
Uncertainty Analysis ◽  
Water Channel ◽  
Planar Motion ◽  
Acquisition Time ◽  
Motion Mechanism ◽  
Towing Tank ◽  
Circulating Water ◽  
Benchmark Study ◽  
Hydrodynamic Derivatives ◽  
Planar Motion Mechanism

Abstract The benchmark experiment research for the maneuverability of a small-scaled ship model is critical for investigating the scaled effect on the maneuvering hydrodynamic derivatives, and validating the CFD technology. Till now, there is little research on the benchmark study and uncertainty analysis for the small-scaled ship which is frequently used in the Circulating Water Channel (CWC). Therefore, an experimental study of the planar motion mechanism (PMM) tests is performed in the CWC of the SJTU. The PMM tests performed in the CWC can avoid some disadvantages of those in the towing tank, such as the limitations on the acquisition time and frequency due to the size of the towing tank, interference of the carriage on the signal acquisition. In addition, the flow field visualization for the tests in the CWC is easier to achieve compared with the experiments in the towing tank, which helps the scholars to understand the characteristic of the wake field during maneuvers. The benchmark ship is the KVLCC2 with a scaled ratio of 1/128.77. The hull forces are recorded and processed to obtain the maneuvering hydrodynamic derivatives. To assess the quality of the acquired data, randomness analysis, stationarity analysis, normality analysis, and statistical convergence are performed for the PMM tests in the CWC for the first time. Finally, the uncertainty analysis (UA) method for the PMM tests performed in the CWC is also developed.

On the planar motion mechanism used in ship model testing

1970 ◽  
Vol 266 (1171) ◽  
pp. 35-61 ◽  
Keyword(s):  
Slow Motion ◽  
Planar Motion ◽  
Motion Mechanism ◽  
Ship Model ◽  
Maritime Literature ◽  
Fluid Forces ◽  
Hydrodynamic Derivatives ◽  
Planar Motion Mechanism ◽  
Buoyancy Forces ◽  
Testing Tank

In the linear theory of small departures from steady reference motions of submarines and ships it is standard practice to employ the idea of hydrodynamic ‘derivatives’. These derivatives permit the magnitudes of fluid forces and moments to be specified. In recent years it has become common to measure the derivatives by means of a - planar motion mechanism ’ which is essentially a device for oscillating a ship (or submarine) model while it is being towed in a testing tank. The derivatives referred to in the maritime literature have invariably been * slow motion derivatives ’. The theory of the planar motion technique is recast in terms of ‘ oscillatory derivatives ’—or, better. ‘ oscillatory coefficients ’, since they are more appropriate for use where the mechanism is concerned. The idea behind these quantities is borrowed from aeronautical practice, but it requires some adaptation because ( a ) ship models work at the water surface, and ( b ) ships and submarines are subject to significant buoyancy forces. There can be little doubt that the planar motion mechanism is a powerful tool and a reappraisal is perhaps timely since the first mechanism of this sort to be installed in the U.K. has recently been commissioned (1968).

Choice of Origin for Body Axes Attached to a Rigid Vehicle

1969 ◽  
Vol 11 (6) ◽  
pp. 551-555 ◽  
Author(s):  
R. E. D. Bishop ◽  
A. G. Parkinson
Keyword(s):  
Equations Of Motion ◽  
Linear Analysis ◽  
Planar Motion ◽  
Test Results ◽  
Centre Of Mass ◽  
Motion Mechanism ◽  
Mass Centre ◽  
Planar Motion Mechanism

The equations of motion of a rigid vehicle are derived in terms of body axes whose origin does not coincide with the centre of mass of the vehicle. The application of the results to the linear analysis of the motion of ships and aircraft is explained. An example is given of the effects of the mass centre being off-set from the origin in calculating oscillatory coefficients from test results obtained with a planar motion mechanism.

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.

Maneuverability Towing Tank Experiments With Manifold Models: Part II — PMM Oscillation Tests

2018 ◽  
Author(s):  
Danyllo de Lima Guedes ◽  
Felipe Augusto de Souza Kleine ◽  
Felipe Santos de Castro ◽  
Daniel Carvalho ◽  
João Lucas Dozzi Dantas
Keyword(s):  
Harmonic Functions ◽  
Forced Oscillations ◽  
Simulation Studies ◽  
Motion Mechanism ◽  
Towing Tank ◽  
Analysis Techniques ◽  
Hydrodynamic Derivatives ◽  
Planar Motion Mechanism ◽  
Manifold Models ◽  
Scaled Models

This work is the Part II of a two-part work, where the influence of geometrical simplifications and modifications in the maneuverability of a manifold were investigated by three 1:13 scaled models in a towing tank. In this work is presented the adopted methods that were used to obtain the hydrodynamic derivatives from forced oscillations motions in a towing tank using a planar-motion-mechanism. In the part I was presented the static drift tests, which were used to complement the tests presented in this paper. The maneuvering hydrodynamic derivatives are obtained by a two part analysis. First, the measured forces, moments and motions time series signals are filtered and decomposed in harmonic functions. Second, regression analysis techniques are applied to the amplitude of these harmonic functions in order to estimate the hydrodynamic derivatives. The results have showed that the simplification of the manifold geometry has a low influence in the hydrodynamic derivatives in contrast to the installation of a larger plate, which modified the manifold maneuverability significantly. The presented investigation in both papers will be used to form a data base for numerical simulation studies for manifolds installation.

A compact motion controller-based planar motion mechanism for captive manoeuvring tests

2021 ◽  
Vol 220 ◽  
pp. 108195
Author(s):  
M. Cansın Özden ◽  
Sertaç Kurdoğlu ◽  
Ersin Demir ◽  
Kadir Sarıöz ◽  
Ömer Gören
Keyword(s):  
Planar Motion ◽  
Motion Controller ◽  
Motion Mechanism ◽  
Planar Motion Mechanism

Prediction of Warship Manoeuvring Coefficients using CFD

2015 ◽  
Author(s):  
C. Oldfield ◽  
M. Moradi Larmaei ◽  
A. Kendrick ◽  
K. McTaggart
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Physical Model ◽  
Test Data ◽  
Model Test ◽  
Verification And Validation ◽  
Planar Motion ◽  
Physical Model Test ◽  
Motion Mechanism ◽  
Planar Motion Mechanism

Verification and validation has been completed for the use of computational fluid dynamics as a practical means of simulating captive manoeuvring model tests. Verification includes spatial and temporal refinement studies. Direct validation includes the comparison of individual steady drift and planar motion mechanism simulations to physical model test data. Rotating arm simulations are validated indirectly on the basis of manoeuvring derivatives developed from the PMM tests. The merits of steady and unsteady simulations are discussed.

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