In order to harness the kinetic energy of marine currents, we propose a novel ocean-current turbine with a horizontal axis. The turbine can be moored to the seabed and function similarly to kites in a water flow. To operate such turbines in a marine current, the resulting rotor torque needs to be canceled. Therefore, the proposed turbine is designed with a float at its top and a counterweight a...

This paper describes a procedure to design robust controllers for Dynamic Positioning (DP) of ships and offshore rigs subjected to the influence of sea waves, currents, and wind loads using H∞ and mixed-μ techniques. To this effect, practical assumptions are exploited in order to obtain a linear design model with parametric uncertainties describing the dynamics of the vessel. Appropriate freque...

Abstract The International Towing Tank Conference (ITTC) suggests that determining the variations of propulsion efficiency can be achieved by model tests may costly and inefficient. This is reason why this paper investigates variation factors under various ship loading conditions computational fluid dynamics (CFD). study proposed a non-iterative method for load reduced time. CFD software Star-C...

In order to solve the towing problem on water of the open caisson in the construction of the large scale bridge efficiently, combining with the towing operation project, the dragged open caisson and environmental data, etc. we design and produce the open caisson physical model and configure the test environment, use the force cell to collect real-time experimental data, analyze and demonstrate ...

The paper presents velocity measurements, using particle image velocimetry, as well a reconstruction of hydrodynamic pressures for the analysis fast ships. Stereoscopic PIV measurements with towed underwater system are conducted during towing tank tests to obtain field in bow region ship at speeds up Fr=0.8. While model is kept fixed trim and sinkage, multi-plane total 68 measurement planes rec...

In this paper a nonlinear thrust controller for fixed pitch marine propellers with torque loss estimation and an antispin strategy is presented. The controller, designed to operate in the four-quadrant plane composed by the shaft speed and the vessel speed, is a combination of a thrust controller developed for calm/moderate sea states and an anti-spin strategy to reduce power peaks and wear-and...

In this paper a nonlinear thrust controller for a fixed pitch marine propeller with torque loss estimation and an anti-spin strategy is presented. The controller, designed to work in the four-quadrant plane composed by the shaft speed and the vessel speed, is a combination of a thrust controller designed for calm sea conditions and an anti-spin strategy to reduce power peaks and wear-and-tear i...

Flow around a rowing blade is a very complex phenomenon, involving unsteady three-dimensional flow with violent motion of the free surface. However, in the literature, forces acting on blades are modelled using extreme and dubious simplifications. The aim of the present study was to evaluate the influence of free surface and unsteadiness (two physical characteristics that are commonly neglected...

B-spline curves and surfaces and their suitability for ship hull surface definition are discussed. A comparison with other curve and surface definition methods, e.g., cubic splines, Bézier curves, parabolic blending is given. Their use both for ab initio curve and surface generation and for fitting existing offset data is discussed. Comparisons of the data storage requirements are made. The uti...