Mr
Simone Martini
(University of Trieste)
20/06/2018, 14:00
Numerical & experimental hydrodynamics
Paper
In ocean and offshore engineering, Vortex and Wake Induced Vibrations (VIV, WIV) are serious issues related to the design and operational safety of offshore installations/structures.
Vortex Induced Vibrations occur when vortices shed by a blunt freely-moving structure in steady (or unsteady) flow induce an oscillatory force on the structure, mostly in the direction perpendicular to the...
Mr
Pierre Crepier
(MARIN)
20/06/2018, 14:15
Numerical & experimental hydrodynamics
Paper
While most of the current Computational Fluid Dynamics (CFD) work focusing on calm-water seems to be under control, attention is now brought on simulating ships in waves. However, a lot of scatter exists in how those simulations are performed. In particular, no consensus on grid generation and time-stepping guidelines seems to exist when it comes to includes waves in the simulations. From this...
Mr
Sertaç Bulut
(Istanbul Technical University)
20/06/2018, 14:30
Numerical & experimental hydrodynamics
Paper
The prediction and reduction of underwater noise is commercially, militarily and ecologically a very critical issue for maritime industry. Machine noise, propeller noise and flow noise are the main components of underwater noise for submerged bodies. Especially at high flow velocities, flow noise becomes dominant source of underwater noise radiated from these bodies.
In this paper, the...
Dr
Cecilia Leotardi
(National Research Council - Marine Technology Research Institute, CNR-INSEAN)
20/06/2018, 14:45
Numerical & experimental hydrodynamics
Paper
Simulation-based methodologies are widely used for the design of marine vehicles to alleviate the costs of the traditional build-and-test approach. Within this context, high-fidelity simulations are required to accurately predict and possibly optimize the performance of naval vehicles. The objective of the present work is the prediction of resistance and motions of a destroyer-type hull,...
Ms
Mariko Kuroda
(National Maritime Research Institute)
20/06/2018, 15:00
Numerical & experimental hydrodynamics
Paper
Added resistance in irregular waves is generally calculated as the mean value with wave spectrum and frequency response of the added resistance in regular waves. In the calculation, the added resistance in regular waves is assumed to be proportional to square of wave height based on the wave theory. However, from the experiment it is not always proportional. Therefore, the mean value from the...
Francesco Coslovich
(Chalmers University of Technology)
20/06/2018, 15:15
Stability, Seakeeping, Maneuverability
Paper
Optimization of modern hulls when moving in a seaway puts new demands on the computational methods used. Nonlinear effects become important for wave loads and added resistance in waves in presence of large motions.
The purpose of this paper is to present a method which aims to fill the gap between RANSE methods and partly nonlinear panel methods. The method solves the fully nonlinear free...
Mr
Nicola Demo
(SISSA)
21/06/2018, 08:30
Naval ships design & technology
Paper
Shape optimization is a challenging task in many engineering fields, since the numerical solutions of parametric system may be computationally expensive. This work presents a novel optimization procedure based on reduced order modeling, applied to a naval hull design problem. The advantage introduced by this method is that the solution for a specific parameter can be expressed as the...
Marco Tezzele
(SISSA - mathLab)
21/06/2018, 08:45
Naval ships design & technology
Paper
We present the results of the application of a parameter space reduction methodology based on active subspaces (AS) to the hull hydrodynamic design problem. Several parametric deformations of an initial hull shape are considered to assess the influence of the shape parameters, considered on the hull wave resistance. Such problem is extremely relevant at the preliminary stages of the ship...
Mr
Inno Gatin
(University of Zagreb, Croatia)
21/06/2018, 09:00
Numerical & experimental hydrodynamics
Paper
A unique numerical environment for assessing ship resistance using CFD is presented in this paper. Predicting ship resistance in calm water with the Naval Hydro pack can be performed within few hours, including computational grid generation, simulating and result post-processing. Being able to predict the ship resistance within few hours renders CFD a cost-effective design tool, since a hull...
Dr
Simone Mancini
(Eurisco Consulting Srls)
21/06/2018, 09:15
Yacht, pleasure craft design and inland vessels design
Paper
Stepped planing hulls enable the feasibility of running at relatively low drag-lift ratio by means of achieving more optimal trim angle at high speeds than a similar non-stepped hull. Furthermore, stepped planing hulls ensure good dynamic stability and seakeeping qualities at high speeds. However, there is no precise method to analyze these hulls over the full range of operating speeds. For...
Mr
Riccardo Pigazzini
(Department of Engineering and Architecture - University of Trieste)
21/06/2018, 09:30
Numerical & experimental hydrodynamics
Paper
An extensive campaign of model and full scale experimental tests as well as of numerical computations, aimed at the prediction of the hydrodynamic performances of a 65 ft motoryacht in calm water and in waves, is undertaken within the framework of the Project SOPHYA - Seakeeping Of Planing Hull YAchts, co-financed by Friuli-Venezia
Giulia Region in the field of joint industrial and academic...
Dr
Andrey Sukhorukov
(Central Design Bureau for Marine Engineering «Rubin», Saint-Petersburg)
21/06/2018, 09:45
Numerical & experimental hydrodynamics
Paper
This study defines hydrodynamic characteristics of underwater gliders based upon numeric solution of Reynolds-averaged Navier-Stokes equation. Methodological aspects of determination of coefficients of rotary derivatives of hydrodynamic forces and moments of underwater objects based on mechanism of "sliding computation meshes" implemented in many computing software packages of mechanics of...
Prof.
Ermina Begovic
(University of Naples Federico II)
21/06/2018, 10:00
Stability, Seakeeping, Maneuverability
Paper
Operating in high speed regime leads to hydrodynamic lift and displaced volume diminution, consequently the boat experiences the changing of trim, rise of centre of gravity and wetted surface decreasing. Standard linear model, for planing hulls seakeeping assessment, based on the linear free surface condition and small changes in wetted surface are not applicable at all.
This work is focused...
Prof.
Valerio Ruggiero
(University of Messina)
21/06/2018, 11:00
Conceptual and practical ship design
Paper
Compared to all traditional fast ferries, Hydrofoil represents the best solution for the fuel economy and reduction of ship motions. These advantages are still undisputed primates of the wing supported means.
It is then wondering why hydrofoils are not so used in modern commercial fleets even despite the high management costs from the maintenance point of view, the initial acquisition cost...
Dr
Fabrizio Ortolani
(CNR-INSEAN)
21/06/2018, 11:15
Ship propulsion, machinery and systems
Paper
During operative scenarios, the propeller can experience an inflow substantially different from the one considered in the design phases and the 3D character of the flow gives onset to a complete system of loads. The quantification of these loads is of paramount importance to assess the reliability of mechanical structures, the comfort on-board due to vibrations and the effects on the dynamic...
Dr
Fabiana Miglianti
(DITEN - University of Genoa - Genova - Italy)
21/06/2018, 11:30
Numerical & experimental hydrodynamics
Paper
For the propeller acoustic characterization, experimental tests in model scale are the currently established methods, however they are affected by uncertainties mostly due to scale effects. For this reason, it is difficult to consistently reproduce in model scale some of full scale functioning conditions.
To overcome this it is interesting to define empirical formulations to shape the most...
Mr
Fatih Cuneyd Korkmaz
(Yildiz Technical University)
21/06/2018, 11:45
Numerical & experimental hydrodynamics
Paper
Liquid sloshing cause ship tanks surface damages and affects ship motions. This phenomenon has been analyzed by rectangular tank model experimentally. Partially filled tank have been experienced and excited various frequency range by direction of sway. Experiments have been carried out with ordinary tank and baffled tank which is placed middle of tank base. Four different water levels have...
Mr
Razvan Gabriel Plingu
("Dunarea de Jos" University of Galati, Romania)
21/06/2018, 12:00
Yacht, pleasure craft design and inland vessels design
Paper
The hydrodynamic resistance of the sailing yacht is strongly influenced by both the large appendages and significant heeling angles, respectively.
In order to evaluate the components of the hydrodynamic resistance the theoretical approach was based on the method proposed by Larson and Eliasson. The residuary resistance was calculated by using the regression formula proposed by Gerritsma...
Mr
paolo becchi
(CETENA S.p.A.)
21/06/2018, 12:15
Ship propulsion, machinery and systems
Paper
The last international recommended procedures and normatives provide detailed guidelines and formulation for the execution of speed and power sea trials and the analysis of the results. For this reason it starts to be necessary to analyze the data directly onboard as the trials are completed and define the effective contractual speed and power condition of the ship. CETENA recently improved...
Mr
Giovanni Alberto Di Mare
(Università degli Studi di Genova)
21/06/2018, 12:30
Ship propulsion, machinery and systems
Paper
The paper refers on a research activity developed at DREAMS Lab of the University of Genoa (Italy), focused on experimental application of air-bubbling technique on a hull model. With this method the injection of compressed air on the bottom of the model generates air bubbles modifying the boundary layer; measurements are implemented in towing tank.
The hull model has got a large flat bottom...
Dr
Juan González-Adalid
(SISTEMAR)
22/06/2018, 14:30
Ship propulsion, machinery and systems
Paper
Most of the traditional procedures for the design of conventional propellers do not yield reliable outcomes in the case of unconventional propellers, for which high-fidelity prediction of performance characteristics are necessary. It is generally understood and recognized, for instance, that the standard ITTC’78 procedure for model to full-scale extrapolation of performance is not reliable in...
Mr
Daniele Bruno
(MICAD s.r.l.), Mr
Daniele Malgieri
(MICAD s.r.l.)
22/06/2018, 14:45
Ship propulsion, machinery and systems
Paper
The shaft-less rim-driven thruster (RDT) can provide many advantages over traditional ship propulsion plants including enhanced onboard comfort and propulsion efficiency, locations arrangement flexible installation, light weight and compact size. For this reason, during last years it become an attractive ship propulsion device in the marine industry.
Within the project P. E. R. Na....
Mrs
Marta Cianferra
(University of Trieste)
22/06/2018, 15:00
Numerical & experimental hydrodynamics
Paper
In the present work simulations of an isolated marine propeller are carried out using Large Eddy simulation and the acoustic field is reconstructed by applying the advective Ffowcs-Williams and Hawkings equation. We reproduce a propeller well studied in literature (https://www.sva-potsdam.de/en/potsdam-propeller-test-case-pptc/) for a single value of the advance ratio.
We use the dynamic...
Dr
Mitja Morgut
(Università degli Studi di Trieste)
22/06/2018, 15:15
Numerical & experimental hydrodynamics
Paper
In modern market scenarios, the competitiveness of an enterprise is determined, beyond the quality of the product, by its time to market. Thus, nowadays, the computational fluid dynamics (CFD) technologies are extensively used for design purposes allowing the - in general - more expensive and time consuming experimental tests to be performed only at the final stages of the project....
Dr
Liviu Crudu
(“Dunarea de Jos” University of Galati, Faculty of Naval Architecture and NASDIS Consulting, Galati), Dr
Oana Marcu
(“Dunarea de Jos” University of Galati, Faculty of Naval Architecture)
22/06/2018, 15:30
Numerical & experimental hydrodynamics
Paper
During the early design stages a fairly evaluation of propeller induced forces on the aft part of a Ro-Ro ship could become of paramount importance and, often, very difficult to be handled. The complex hydrodynamic interactions and the limited ways of wake factor evaluation, when experimental values are not available, lead to the necessity to consider Computational Fluid Dynamic tools in order...
Mr
Gianluca Gustin
(FINCANTIERI)
22/06/2018, 15:45
Conceptual and practical ship design
Paper
CFD simulations are becoming more and more reliable and the increasing computational power are making them a convenient tool to investigate complex phenomena and to reproduce the experimental tests. In the hydrodynamic design process the correct evaluation of the self propulsion performance is an essential item to access the true performances of the ship. This paper deal with a CFD...
Mr
Cagatay Sabri Koksal
(Istanbul Technical University)
22/06/2018, 16:00
Numerical & experimental hydrodynamics
Paper
A new research project, involving the construction of a modern, large, closed-circuit depressurized high-speed water tunnel to support the detailed hydro-acoustic, hydrodynamic, cavitation and flow visualization based experimental campaigns, has been started in Istanbul Technical University. The present paper covers the fundamental viscous flow computations concerning the design of the...
