Experimental investigation on the effects of froude number on manoeuvring characteristic of a research vessel
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...
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10 Sep 2021
TL;DR: In this paper, the performance of a proportional derivative type fuzzy controller with Mamdani interface scheme for dynamic positioning of an oceanographic research vessel (ORV) by numerical simulation is investigated.
Abstract: A dynamic positioning (DP) system is a computer-controlled system which maintains the positioning and heading of ship by means of active thrust. A DP system consist of sensors, observer, controller and thrust allocation algorithm. The purpose of this paper is to investigate the performance of proportional derivative type fuzzy controller with Mamdani interface scheme for dynamic positioning of an oceanographic research vessel (ORV) by numerical simulation. Nonlinear passive observer is used to filter the noise from the position and orientation. A nonlinear mathematical model of the ORV is subjected to the wave disturbance ranging from calm to phenomenal sea. Robustness and efficiency of the fuzzy logic controller is analysed in comparison with the multivariable proportional integral derivative (PID) and the linear quadratic regulator (LQR) controller. A simplified constrained linear quadratic algorithm is used for thrust allocation. The frequency response of the closed loop system with different controllers is analysed using the bode plot. The stability of controller is established using the Lyapunov criteria.
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01 Jan 2017TL;DR: In this article, a series of model tests is described to determine the effect of forward speed on hydrodynamic derivatives of a monohull planing craft and the variations of the hydrodynamics by forward speed are derived.
Abstract: The calculation of unknown hydrodynamic derivatives of the equations of motion is the first step to estimate ship maneuverability and dynamic stability. These derivatives can be obtained theoretically, experimentally and numerically. Despite the development of the oblique towing model test to measure the hydrodynamic derivatives of displacement ships, limited experimental results are available for hydrodynamic derivatives of high speed crafts and speed dependency of the hydrodynamic derivatives is not understood well. In this paper a systematic series of model tests is described to determine the effect of forward speed on hydrodynamic derivatives of a monohull planing craft and the variations of the hydrodynamic derivatives by forward speed are derived. According to the results, hydrodynamic derivatives of planing hull are dramatically changed by variations of forward speed. Moreover, it is not possible to introduce a constant hydrodynamic derivative in the all the ranges of drift angle. Thus, the method of known constant hydrodynamic derivatives is not applicable to the simulation of planing craft maneuvering and variable hydrodynamic derivatives should be applied.
2 citations
25 Sep 2018
TL;DR: In this paper, 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.
Abstract: 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.
1 citations
01 Jan 1994
1 citations
"Experimental investigation on the e..." refers methods in this paper
...Same ship was used to further investigate the variation in PMM forces at different speed (Wellicome et al. 1994)....
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01 Jan 1994
1 citations
"Experimental investigation on the e..." refers methods in this paper
...Same ship was used to further investigate the variation in PMM forces at different speed (Wellicome et al. 1994)....
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1 citations
"Experimental investigation on the e..." refers background in this paper
...Rameesha and Krishnankutty (2018) studied variation in hydrodynamic derivatives with Froude number for s175 container....
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