In this paper, we introduce a three-dimensional numerical method for computing the wake behind a flat plate advancing perpendicular to the flow. Our numerical method is inspired by the panel method of J. Katz and A. Plotkin [J. Katz and A. Plotkin, Low-speed Aerodynamics, 2001] and the 2D vortex blob method of Krasny [R. Krasny, Lectures in Appl. Math., 28 (1991), pp. 385–402]. The accuracy of ...

The idealized raked-wedge hull has a triangular waterplane with its base of finite beam at the transom stern and its apex of zero beam at the stem of the bow. The sections are rectangular and the draft increases linearly from zero at the stern to the maximum draft at the bow. This hullform provides a challenge for the traditional linear wave-making theory. Nevertheless, there is good agreement ...

This paper is a follow-up of a companion paper by Hassani et al. (2012b) on a control design methodology for Dynamic Positioning (DP) of marine vessels and offshore rigs subjected to the influence of sea waves, currents, and wind loads using mixed-μ synthesis. The present paper describes the results of a design exercise in which robust controllers were designed for a representative vessel. Its ...

An experimental investigation has been carried out to document and relate the frictional resistance and roughness texture of painted surfaces smoothed by sanding. Hydrodynamic tests were carried out in a towing tank using a flat plate test fixture towed at a Reynolds number ~ReL ! range of 2.8310 25.5310 based on the plate length and freestream velocity. Results indicate an increase in friction...

Abstract Aerial and underwater drones are one of the most attractive technologies to a large number applications, extending from surveillance natural reserves monitoring structures. For these reasons, innovative uncommon applications constantly appearing. Within this context, capable operate continuously efficiently in air water can extend standard aerial capabilities allowing inspections harbo...

Still water resistance tests for a 2.3-m model of a Harley surface effect ship (HSC-SES), completed in August 2002, are presented. Few published studies of such a SES exist, and none provide useful measurements of the wetted surface area, which is needed to extrapolate results and predict full-scale HSC-SES performance. Here, estimates of wavemaking drag are made using free-surface elevations m...

Transient regimes arise when the propeller of a ship is operating in extreme seas, where ventilation and in-and-out of water effects results in loss of propeller thrust. By introducing Lyapunov based controller state reset, the performance in transient regimes may be increased without influencing the performance in calm seas. Improvements have been presented previously for dynamically positione...

This thesis describes the results of over 2000 experimental runs conduced at the MIT Ship Model Testing Tank. A rake of constant temperature anemometers is employed to study the spanwise velocity correlation and the vertical velocity profile downstream of a vibrating cylinder. Experiments involve either free vibration implemented through a force feedback system or forced sinusoidal motion. All ...

The aim of this study was an analysis of the time required to swim to a victim and tow them back to shore, while perfoming the flutter-kick and the dolphin-kick using fins. It has been hypothesized that using fins while using the dolphin-kick when swimming leads to reduced rescue time. Sixteen lifeguards took part in the study. The main tasks performed by them, were to approach and tow (double ...

The necessity to improve the hydrodynamic performance of marine vessels has confirmed urgency conducting further investigations on biomimetic tubercles. In this work, towing tank tests were conducted at a range speeds conveniently prepared flat plates coated with 3D printed humpback whales mimicked results showed that artificial tubercles induced drag reduction up 1.3% compared bare plate. Foll...