1,721,021 research outputs found
Prediction of ship-lock interaction by using a modified potential flow solver
Get PDFShip-lock interactions are very difficult to predict. The hydrodynamics of ships entering (or leaving) a lock is always accompanied with shallow water and bank effects. When a ship enters or leaves a lock with a closed end, a so-called piston effect will be provoked due to the translation waves trapped in the gap between the ship and the lock door. Meanwhile, as the water is accumulating or evacuating in a lock with closed end, a return flow will be generated. The nature of the complex hydrodynamics involved in ship-lock interactions have not been fully understood so far and it is very challenging to develop a mathematical model to predict ship hydrodynamics in a lock. In the 4th MASHCON, the author presented his original simulation results of the hydrodynamic forces on a ship when it entered a lock based on a potential flow solver MHydro. A very large discrepancy was found between the numerical results and experimental measurements. It was con-cluded that the potential flow theory failed to predict the hydrodynamic forces on a ship when it entered a lock. Over the past two years, the author has continuously worked on ship-to-lock problem and proposed amodified potential flow method by adding a proper return flow velocity to the boundary value problem. The results showed the modified method could predict the resistance and lateral forces very well. However, it failed to predict the yaw moment due to the flow separation at the lock entrance
Drag characteristics of newly applied marine coatings and potential applications in combination with ultrasonic devices
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Full-scale measurements of vertical motions on ultra large container vessels in Scheldt Estuary
Get PDFFrom September 2017 to July 2018 the Flemish Pilotage executed nine ship measurements on container ships to and from Antwerp. The measurement results were processed by Flanders Hydraulics Research and Ghent University providing 6 DoF motions of the vessels. Furthermore environmental data regarding tide, currents, waves, bathymetry and AIS were processed in order to assess the influence of environmental conditions on the vertical motions of container ships.
The paper presents the vertical ship motions separately for steady and unsteady sinkages in different DoF. As such the relation with ship squat, hydrostatics, sea keeping, turning, steering and ship-to-ship interaction could be assessed and related to the driving parameters such as ship speed, rate of turn, under keel clearance, water density, waves, rudder action and ship meetings
Numerical and experimental study on the wave-body interaction problem with the effect of forward speed and finite water depth in regular waves
Get PDFSailing in shallow water waves with the DTC container carrier : open model test data for validation purposes
Get PDFVariations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
On a pragmatic force criterion for the design of a navigation lock filling and emptying system
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