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Wyniki wyszukiwania dla: SHIP HYDRODYNAMICS
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Supporting Navigator's Decisions By Visualizing Ship Collision Risk
PublikacjaW artykule wprowadzono metodę wizualizacji, która umożliwia nawigatorowi oszacowanie ryzyka kolizji i (w razie konieczności) wybór manewru antykolizyjnego. Metoda jest oparta na wcześniejszej metodzie CTPA, uwzględnia dowolną zadaną domenę statku i jest wystarczająco szybka do zastosowania w okrętowych systemach wspierania decyzji nawigatora.
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Evolutionary Sets of Safe Ship Trajectories: development of the method
PublikacjaThe Evolutionary Sets of Safe Ship Trajectories is a method solving ship encounter situations. The method combines evolutionary approach to planning ship trajectory with some of the assumption of game theory. For given positions and motion parameters the method finds a near optimal set of safe trajectories of all ships involved in an encounter. The version presented here is an updated one and its authors have tested extensively...
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Evolutionary Sets of Safe Ship Trajectories: simulation results
PublikacjaThe Evolutionary Sets of Safe Ship Trajectories is a method solving multi-ship encounter situations. For given positions and motion parameters the method finds a near optimal set of safe trajectories of all ships involved in an encounter. The paper briefly presents foundations of the method and focuses on simulation results for selected test cases based on the Baltic Basin. The computer simulations cover both open waters and restricted...
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Evolutionary Sets of Cooperating Ship Trajectories: COLREGS Compliance
PublikacjaThe paper presents a newly designed improvement to the method of solving multi-ship encounter situations. In general, the method combines some of the assumptions of game theory with evolutionary programming and aims to find optimal set of cooperating trajectories of all ships involved in an encounter situation. The improvement presented here is a new way of modelling some of the COLREGS rules. Due to this change, the method is...
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Assessment of ship squat in shallow water using CFD
PublikacjaReferat zawiera wstęp do problemu modelowania efektów wody ograniczonej przy użyciu komercyjnego programu Fluent opartego na metodzie elementów skończonych.
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Assessment of ship squat in shallow water using CFD
PublikacjaArtykuł zawiera wstęp do problemu modelowania efektów wody ograniczonej przy użyciu komercyjnego programu Fluent opartego na metodzie elementów skończonych.
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An analysis of ship escort and convoy operations in ice conditions
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Evolutionary approach to solving multi-ship encounter situations
PublikacjaW artykule wprowadzono nowe podejście do rozwiązywania sytuacji spotkań wielu statków poprzez połączenie założeń teorii gier z programowaniem ewolucyjnym. Spotkanie wielu statków jest zamodelowane jako gra rozgrywana przez ''myślących graczy'' - statki o różnych, potencjalnie zmiennych strategiach. Rozwiązanie - zbiór kooperujących (niekolidujących) trajektorii jest znajdowane za pomocą algorytmu ewolucyjnego.
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Advantages of waterjet ship propulsion in inland waterway transport
PublikacjaPoddano analizie napęd strugowodny statku z punktu widzenia następujących aspektów transportu śródlądowego:- ograniczona szerokość i głębokość drogi wodnej,- możliwości osadzenia statku na mieliźnie,- ścisłe ograniczenia ekologiczne,- ograniczona szybkość ruchu statku.
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Game theory, as a way for integrating of ship control systems
PublikacjaReferat przedstawia koncepcję wykorzystania algorytmów zastosowanych w teorii gier do zintegrowania układów sterowania statków, takich jak układ sterowania kursu i trajektorii statku, układ sterowania napędu statku, układ sterowania stabilizacji kołysań bocznych statku, itp. Jest to koncepcja oryginalna.
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The influence of compensate coils on own ship magnetic field
PublikacjaA ferromagnetic object placed in the earth magnetic field causes a local disturbance in this field distribution. The field distribution disturbance is a function of many arguments like the dimensoins and shape of the object, its ferromagnetic properties ande its positon in relation to the earth magnetic field. in order to minimize the influence of this disturbance one places compensate coils on the ship. Some chosen results of...
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Approach to evaluation of time to the critical degradation of ship pipelines
PublikacjaIn the article an approach to the problem of estimating time to the critical degradation of ship pipelines is considered. Such an assessment would consist of six stages. The fundamental idea is to include to the estimation of time to failure of pipelines such elements like: materials that the pipelines are made, destructive physical phenomena taking place in them and applied means of protection. The result of that evaluation should...
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REDUNDANCY AS A WAY INCREASING RELIABILITY OF SHIP POWER PLANTS
PublikacjaOne of key ways of assuring a high level of reliability of a ship power plant is to design redundancy of its structural elements, for example redundancy of prime drivers, drivelines etc. This paper deals with issues related to the redundancy as a way increasing dependability of the ship power and propulsion systems. Especially, fundamental characteristics of dependability, major design strategies influencing the reliability, and...
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APPLICATION OF REDUNDANCY IN SHIP POWER PLANTS OF OFFSHORE VESSEL
PublikacjaPower and propulsion systems of offshore units must be of a very high level of reliability. The loss of ability to perform functions of their components causes generally to very high economic losses, which may be increased by unused the weather window resulting to postponing the planned offshore operations. To ensure carrying out so expensive offshore operations in the most reliable way, various types of redundancies are built-in...
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In Search of Naval Beauty. Historical Study of Ship Architecture
PublikacjaDesigning ships is no mean achievement. In the old days, constructors focused on making their ships visually appealing, while paying scant regard to the living conditions of the crew. Such an approach reflected the state of the art in ship building at the time as well as the social order prevalent in those days. A breakthrough came no earlier than at the turn of the 19th / 20th centuries. The industrial revolution brought along...
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VARIANT DESIGNING IN the PRELIMINARY SMALL SHIP DESIGN PROCESS
PublikacjaShip designing is a complex process, as the ship itself is a complex, technical multi-level object which operates in the air/water boundary environment and is exposed to the action of many different external and internal factors resulting from the adopted technical solutions, type of operation, and environmental conditions. A traditional ship design process consists of a series of subsequent multistage iterations, which gradually...
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A Framework of a Ship Domain-based Collision Alert System
PublikacjaThe paper presents a framework of a planned ship collision alert system. The envisaged system is compliant with IMO Resolution MSC.252 (83) “Adoption of the revised performance standards for Integrated Navigation Systems (INS)”. It is based on a ship domain-oriented approach to collision risk and introduces a policy of alerts on dangerous situations. The alerts will include cautions, warnings and alarms, which will be triggered...
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Quantitative Assessment of Operation of Ship Main Diesel Engine
PublikacjaOperation of ship propulsion system is associated with realization of definite operational goals. If to elements of the system the operational reliability strategy could be applied, the situation would be very simple as existing conditions would unambiguously determine application of means being on hand. However decision to reject application of the strategy (even if hypothetical) becomes obvious with a view of necessity of ensuring...
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Evolutionary Sets of Safe Ship Trajectories: Evaluation of Individuals
PublikacjaThe paper presents a description of the evaluation phase of the Evolutionary Sets of Safe Ship Trajectories method. In general, the Evolutionary Sets of Safe Ship Trajectories method combines some of the assumptions of game theory with evolutionary programming and finds an optimal set of cooperating trajectories of all ships involved in an encounter situation. While developing a new version of this method, the au-thors decided...
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COLREGS compliance in Evolutionary Sets of Cooperating Ship Trajectories
PublikacjaIn general, Evolutionary Sets of Cooperating Ship Trajectories combine some of the assumptions of game theory with evolutionary programming and aim to find optimal set of cooperating trajectoriesof all ships involved in an encounter situation. In a two-ship encounter situation the method enables the operator of an on-board collision-avoidance system to predict the most probable behaviour of atarget and to plan the own manoeuvres...
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Mathematical Models in Design Process of Ship Bow Thrusters
PublikacjaThe paper describes an application of simulation models for computer-aided design of ship bow thrusters. Generation of simulation models of ship bow thruster requires development and verifying of mathematical models of system component elements. Using the results of simulation the expert system is able to determine, that the rules of classification societies are met. Design procedures and mathematical models are part of an expert...
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Mathematical Models in Design Process of Ship Bow Thrusters
PublikacjaThe presentation is about an application of simulation models for computer-aided design of ship bow thrusters. Generation of simulation models of ship bow thruster requires development and verifying of mathematical models of system component elements. Using the results of simulation the expert system is able to determine, that the rules of classification societies are met. Design procedures and mathematical models are part of an...
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An analysis of domain-based ship collision risk parameters
PublikacjaAccording to a lot of contemporary research on ship collision avoidance the classic approach parameters – distance at closest point of approach (DCPA) and time to the closest point of approach (TCPA) – are not sufficient for estimating ship collision risk and for planning evasive manoeuvres. Consequently new measures are introduced, often utilizing the concept of a ship domain. Their drawback, up to this point, was the lack of...
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HYBRID ENERGY SYSTEM FOR A CLASSIC SHIP POWER PLANT
PublikacjaThe article presents a brief overview of hybrid energy systems used on ships. The area of their application is outlined. The benefits of using such systems are also indicated. Then, the classic ship power plant is defined. The most important part of the article is a proposal how to modify a classic engine room by using a hybrid energy system. The idea is: to accumulate a part of electricity in areas where it is allowed to burn...
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UNDERWATER NOISE GENERATED BY A SMALL SHIP IN THE SHALLOW SEA
PublikacjaStudy of the sea noise has been a subject of interest for years. The first work of this scope were published at the turn of the twentieth century by Knudsen (KNUDSEN et al., 1948) and G. Wenz (WENZ, 1962). Disturbances called "shipping noise" are one of the important components of the sea noise. In this work the results of an experimental research of underwater noise produced by a small ship of a classic propulsion are...
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Customized crossover in evolutionary sets of safe ship trajectories
PublikacjaThe paper presents selected aspects of evolutionary sets of safe ship trajectories-a method which applies evolutionary algorithms and some of the assumptions of game theory to solving ship encounter situations. For given positions and motion parameters of the ships, the method finds a near optimal set of safe trajectories of all ships involved in an encounter. The method works in real time and the solutions must be returned within...
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Evolutionary Sets of Safe Ship Trajectories: Evaluation of Individuals
PublikacjaThe paper presents a description of the evaluation phase of the Evolutionary Sets of Safe Ship Trajectories method. In general, the Evolutionary Sets of Safe Ship Trajectories method combines some of the assumptions of game theory with evolutionary programming and finds an optimal set of cooperating trajectories of all ships involved in an encounter situation. While developing a new version of this method, the authors decided to...
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Evolutionary Planning of Safe Ship Tracks in Restricted Visibility
PublikacjaThe paper presents the continuation of the author's research on ship track planning by means of Evolutionary Algorithms (EA). The presented method uses EA to search for an optimal set of safe tracks for all ships involved in an encounter. Until now the method assumed good visibility – compliance with standard rules of the Convention on the International Regulations for Preventing Collisions at Sea (COLREGS, 1972). However, in restricted...
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A comparative performance assessment of a hydrodynamic journal bearing lubricated with oil and magnetorheological fluid
PublikacjaThis work presents the investigation results of a journal bearing lubricated with magnetorheological fluid that is activated by a local constant magnetic field to vary both the local flow resistance and pressure. The bearing performance is assessed via Finite Element Modelling (FEM) and results are corroborated by experiments. The FEM model uses the Bingham model to describe the fluid film. A dedicated test rig is used to assess...
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Experimental Research Concerning Hydrodynamic Clutches Controlled by Increasing Distance Between Rotors
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Analysis of the Hydrodynamic Properties of the 3-Column Spar Platform for Offshore Wind Turbines
PublikacjaThe article presents a design of a floating platform for offshore wind turbines. The concept is a modification of the Spar design and consists of three variable section columns connected to each other by a ballast tank in the lower part of the platform. This solution makes it possible to influence the position of the centre of buoyancy and the centre of mass of the structure. Compared to the classic Spar platform structure, the...
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The role of hydrodynamic cavitation in tuning physicochemical properties of food items: A comprehensive review
PublikacjaBackground: Today, food processing industries are looking for alternative technologies with an eco-friendly character for the processing of food, beverages and agricultural crops. Ideally, such technologies may preserve the original properties of the food products while reaching their primary target of application. Scope and approach: At this point, hydrodynamic cavitation (HC) is recognized as one of the potential technologies...
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Effect of manufacturing errors of the pad sliding surface on the performance of the hydrodynamic thrust bearing
PublikacjaIn the present study, investigation of the effect of manufacturing errors on the performance of large tilting pad thrust bearings has been performed, following a CFD-based Thermohydrodynamic analysis of a single pad. A 3D model has been generated, including the pad, the lubricant film and the corresponding part of the collar. The pad has been assumed to be deformed about the pivot point, due to thrust loading. Manufacturing errors...
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Morphologic and hydrodynamic conditions of Hel Peninsula's abrasion in the Kuźnica region (southern Baltic)
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The Influence of Hydrodynamic Conditions in a Laboratory-Scale Bioreactor on Pseudomonas aeruginosa Metabolite Production
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MODELLING OF THE VISCOSITY EFFECT OF HEAVE PLATES FOR FLOATING WIND TURBINES BY HYDRODYNAMIC COEFFICIENTS
PublikacjaOne of the methods of modelling the movement of floating wind turbines is the use of the diffraction method. However, this method does not take into account the influence of viscosity; therefore, in many cases, it needs to be extended with a matrix of appropriate coefficients. The effect of viscosity causes both the added mass coefficient and the damping coefficient to increase. The determined coefficients were entered into the...
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Klocki samopompujące w łożyskach hydrodynamicznych = Self-pumping pads in the hydrodynamic bearings
PublikacjaWe współpracy z firmą ALSTOM HYDRO (Szwajcaria), zespół Katedry Konstrukcji i Eksploatacji Maszyn Politechniki Gdańskiej przeprowadził symulacje przepływowe kilku rozwiązań konstrukcyjnych mających na celu zwiększenie niezawodności turbin wodnych. W artykule opisano jedno z takich rozwiązań - tak zwane łożysko z klockami samopompującymi. Głównym celem jest uzyskanie przepływu oleju w układzie smarowania łożyska hydrodynamicznego...
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Field Tests on Hydrodynamic and Hybrid Operation of a Bidirectional Thrust Bearing of a Pump-Turbine
PublikacjaIn vertical shaft pump turbines operating in pumped storage power plants an important role is played by a thrust bearing. Due to the bidirectional character of operation, thrust bearing tilting pads have to be supported symmetrically, which is known to be unfavourable from the point of view of their performance. Large thrust bearings have to be carefully designed so as to minimise excessive thermo-elastic pad deformations. The...
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Network on Chip implementation using FPGAs resources
PublikacjaW artykule przedstawiono implementację sieci typu ''Network on Chip'' w układach FPGA. Sieci typu ''Network on Chip'' stały się bardzo interesującym i obiecującym rozwiązaniem dla systemów typu ''System on Chip'' które charakteryzują się intensywną komunikacją wewnętrzną. Ze względu na inne paradygmaty projektowania nie ma obecnie dostępnych efektywnych platform do budowy prototypów sieci typu ''Network on Chip'' i ich weryfikacji....
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Designing drainage systems – possible application of advanced calculations and hydrodynamical modeling
PublikacjaNowadays we can observe a faster development of drainage systems than ever. This gives us an opportunity to de- sign more efficient systems that can cope with the rapid growth of cities and, what comes with it, impervious surfaces. Here the question arises, whether traditional methods used in drainage system design are potent enough to cope with the emerging prob- lems and difficulties. In this paper we will make...
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Novel strategies to enhance hydrodynamic cavitation in a circular venturi using RANS numerical simulations
PublikacjaHydrodynamic cavitation is a popular advanced oxidation technique and it has received wide range of applications from waste water treatment to the nanoparticles synthesis in recent years. The enhancement of the intensity of the hydrodynamic cavitation is always been an emerging field of research. Within this framework, we have proposed and investigated three distinct strategies to enhance the intensity of cavitation in a circular...
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Thermal and Hydrodynamic Phenomena in the Stagnation Zone — Impact of the Inlet Turbulence Characteristics on the Numerical Analyses
PublikacjaOne of the methods of heat transfer enhancement is utilization of the turbulent impinging jets, which were recently applied, for example, in the heat exchangers. Their positive impact on the heat transfer performance was proven, but many questions related to the origin of this impact are still unanswered. In general, the wall-jet interaction and the near-wall turbulence are supposed to be its main reason, but their accurate numerical...
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Hybrid systems using hydrodynamic cavitation/ultrasound/Fenton processes for effective treatment of wastewater
PublikacjaThe present situation of rapid growth in industrialization generates complex recalcitrant pollutants that are challenging to degrade by conventional wastewater treatment processes. The new generation pollutants such as non-metals in cosmetics or household cleaning chemicals and radioactive compounds which are recalcitrant are the emerging threat to the ecosystem. The headstrong micro and macro pollutants present in wastewater are...
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Experimental comparison of the transition speed of a hydrodynamic journal bearing lubricated with oil and magnetorheological fluid
PublikacjaA journal bearing test bench is used to find the transition speed between the hydrodynamic and mixed lubrication regimes for a modified magnetorheological (MR) fluid. It is shown that the transition speed of the bearing can be reduced by applying a local magnetic field near minimum film when it is lubricated with the MR fluid, and that this will only marginally increase friction. The lubricating performance of the MR fluid is compared...
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Obliczeniowa dynamika płynów w analizie zagadnień smarowaniahydrodynamicznego = CFD in analysis of hydrodynamic lubrication
PublikacjaW pracy przedstawiono wybrane problemy związane z wykorzystaniem obliczeniowej dynamiki płynów (ang. CFD - Computational Fluid Dynamics)do obliczeń łożysk hydrodynamicznych. Omówione zostało zagadnienie przyjmowania rodzaju przepływu w analizie łożyska oraz przyjmowania warunków brzegowych dotyczących wymiany ciepła oraz problem zbieżności obliczeń.
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Integration and Visualization of the Results of Hydrodynamic Models in the Maritime Network-Centric GIS of Gulf of Gdansk
PublikacjaEnsuring of security in the coastal area makes on a seaside countries research in the field of infrastructure spatial information of environmental data. The paper presents the results of work on the construction of this infrastructure by integrating electronic navigational chart with ortophotomaps of coastal areas as well as numerical data from weather and hydrodynamic models. Paper focuses on a problems associated with creating...
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ANALYSIS OF THE LOAD-CARRYING CAPACITY OF A HYDRODYNAMIC WATER-LUBRICATED BEARING IN A HYDROELECTRIC POwER PLANT
PublikacjaThe paper presents an analysis of the load-carrying capacity of a historic hydrodynamic water-lubricated radial bearing of an unconventional segment design installed in the Braniewo Hydroelectric Power Plant. The aim of the calculations was to determine whether the bearing operates in the conditions of hydrodynamic or mixed lubrication, as well as to establish the optimal geometry of the axial grooves allowing for the highest load-carrying...
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Field tests on hydrodynamic and hybrid operation of a bi-directional thrust bearing of a pump-turbine
PublikacjaIn vertical shaft pump turbines operating in pumped storage power plants an important role is played by a thrust bearing. Because of bi-directional character of operation, thrust bearing tilting pads have to be supported symmetrically, which is known to be unfavourable from the point of view of their performance. Large thrust bearings have to be carefully designed so as to minimise excessive thermo-elastic pad deformations. The...
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Accident susceptibility index for a passenger ship-a framework and case study
PublikacjaThe continuous monitoring and assessment of operational vulnerability and accident susceptibility of passenger ships is crucial from the perspective of ship and passenger safety. Despite the existing solutions for vulnerability monitoring, stemming mainly from watertight door operations, a comprehensive framework for accident susceptibility assessment and monitoring is missing in the literature. Therefore, this paper offers a...
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A Method of Assessment of the Liquid Sloshing Impact on Ship Transverse Stability
PublikacjaLiquid sloshing phenomenon taking place in partly filled ships? tanks directly affects the stability of a vessel. However, only static calculations are carried out onboard ships nowadays and static transfer of liquid weight is taken into account in the course of routine stability calculation. The paper is focused on a dynamic heeling moment due to liquid sloshing in tanks onboard ships. The set of numerical simulations of liquid...