scholarly journals Minimum Propulsion Power Assessment of a VLCC to Maintain the Maneuverability in Adverse Conditions

2021 ◽  
Vol 9 (11) ◽  
pp. 1287
Author(s):  
Peiyuan Feng ◽  
Shukui Liu ◽  
Baoguo Shang ◽  
Apostolos Papanikolaou
Keyword(s):  
Added Resistance ◽  
Regulatory Requirements ◽  
Adverse Conditions ◽  
Know How ◽  
Propeller Design ◽  
Routine Design ◽  
Power Regulation ◽  
New Guidelines ◽  
Formula Method ◽  
Propulsion Power

The International Maritime Organization (IMO) Guidelines for Determining Minimum Propulsion Power to Maintain the Maneuverability in Adverse Conditions is the sole regulation imposed on the routine design and approval of all new-built ships as a part of EEDI requirements. This study reviews the development of the guidelines and summarizes the recent amendments of MEPC76(2021). The present assessment is conducted for a new VLCC design following the new guidelines aiming at investigating the influence of alternative wave added resistance evaluation methods and the propeller design features on the assessment results. It is found that the most simple empirical formula method proposed by MEPC76 is not conservative enough, as could have been expected. On the other hand, spectral analysis methods based on empirically obtained and properly validated wave added resistance responses can produce consistent results. Moreover, discussions are made from the perspective of propeller design to meet the regulatory requirements. It is pointed out that the light running margin is a key design parameter, and propellers with larger light running margins are more advantageous for satisfying the minimum propulsion power regulation, thus ensuring the navigation safety in adverse conditions. These obtained insights and know-how can support the engineers in obtaining optimal design solutions.

Head Wave Simulation of a KCS Model Using OpenFOAM for the Assessment of Sea-Margin

2021 ◽  
Author(s):  
Hafizul Islam ◽  
C. Guedes Soares
Keyword(s):  
Head Wave ◽  
Container Ship ◽  
Added Resistance ◽  
Free Condition ◽  
Wave Simulation ◽  
Calm Water ◽  
Sinkage And Trim ◽  
Simulation Results ◽  
Design Speed ◽  
Propulsion Power

Abstract The paper presents calm water and head wave simulation results for a KRISO Container Ship (KCS) model. All simulations have been performed using the open source CFD toolkit, OpenFOAM. Initially, a systematic verification study has been performed using the ITTC guideline to assess the simulation associated uncertainties. After that, a validation study has been performed to assess the accuracy of the results. Next, calm water simulations have been performed with sinkage and trim free condition at varying speeds. Later, head wave simulations have been performed with heave and pitch free motion. Simulations were repeated for varying wave lengths to assess the encountered added resistance by the ship in design speed. The results have been validated against available experimental data. Finally, power predictions have been made for both calm water and head wave cases to assess the required propulsion power. The paper tries to assess the validity of using 25% addition as sea margin over calm water prediction to consider wave encounters.

scholarly journals ANALYSIS OF THE HISTORICAL ALLEES OF UFA

2020 ◽  
Vol 35 (1) ◽  
pp. 166-176
Author(s):  
L.I. Egorova ◽  
◽  
E.S. Karimova ◽  
Keyword(s):  
Spatial Planning ◽  
Regulatory Requirements ◽  
Hygienic Condition ◽  
Adverse Conditions ◽  
Historical Significance ◽  
Design Structure ◽  
The City

The article considers four alleys of the city of Ufa. The basic regulatory requirements are presented and the results of the analysis of the design structure of objects are presented. The sanitary and hygienic condition of the territory, the planning structure, etc. A balance of the areas of the territory was made on the basis of the constructed alignment drawings. The alleys considered are straight in regular and landscape styles. Plantings in Savushkino the alley – bunk, the rest single storey. Trees are free-growing, with a compact crown, durable and resistant to adverse conditions. The main breed is Linden, due to the fact that Ufa is included in its territorial growth. These alleys are popular among the population because of their historical significance and worthy spatial planning structure.

scholarly journals A Framework of Numerically Evaluating a Maneuvering Vessel in Waves

2020 ◽  
Vol 8 (6) ◽  
pp. 392 ◽  
Author(s):  
Zhitian Xie ◽  
Jeffrey Falzarano ◽  
Hao Wang
Keyword(s):  
Wave Loads ◽  
Environmental Loads ◽  
Adverse Conditions ◽  
Damping Effect ◽  
Hydrodynamic Phenomenon ◽  
Calm Water ◽  
Wave Effects ◽  
Maneuvering In Waves ◽  
Wave Drift Damping ◽  
Propulsion Power

Maneuvering in waves is a hydrodynamic phenomenon that involves both seakeeping and maneuvering problems. The environmental loads, such as waves, wind, and current, have a significant impact on a maneuvering vessel, which makes it more complex than maneuvering in calm water. Wave effects are perhaps the most important factor amongst these environmental loads. In this research, a framework has been developed that simultaneously incorporates the maneuvering and seakeeping aspects that includes the hydrodynamics effects corresponding to both. To numerically evaluate the second-order wave loads in the seakeeping problem, a derivation has been presented with a discussion and the Neumann-Kelvin linearization has been applied to consider the wave drift damping effect. The maneuvering evaluations of the KVLCC (KRISO Very Large Crude Carrier) and KCS (KRISO Container Ship) models in calm water and waves have been conducted and compared with the model tests. Through the comparison with the experimental results, this framework had been proven to provide a convincing numerical prediction of the horizontal motions for a maneuvering vessel in waves. The current framework can be extended and contribute to the IMO (International Maritime Organization) standards for determining the minimum propulsion power to maintain the maneuverability of vessels in adverse conditions.

scholarly journals Evaluation of Different Deep-Learning Models for the Prediction of a Ship’s Propulsion Power

2021 ◽  
Vol 9 (2) ◽  
pp. 116
Author(s):  
Panayiotis Theodoropoulos ◽  
Christos C. Spandonidis ◽  
Nikos Themelis ◽  
Christos Giordamlis ◽  
Spilios Fassois
Keyword(s):  
Neural Network ◽  
Deep Learning ◽  
Analytical Techniques ◽  
Learning Models ◽  
Feed Forward Neural Network ◽  
Volume Increase ◽  
Adverse Conditions ◽  
Number Of Layers ◽  
The Neural Network ◽  
Propulsion Power

Adverse conditions within specific offshore environments magnify the challenges faced by a vessel’s energy-efficiency optimization in the Industry 4.0 era. As the data rate and volume increase, the analysis of big data using analytical techniques might not be efficient, or might even be infeasible in some cases. The purpose of this study is the development of deep-learning models that can be utilized to predict the propulsion power of a vessel. Two models are discriminated: (1) a feed-forward neural network (FFNN) and (2) a recurrent neural network (RNN). Predictions provided by these models were compared with values measured onboard. Comparisons between the two types of networks were also performed. Emphasis was placed on the different data pre-processing phases, as well as on the optimal configuration decision process for each of the developed deep-learning models. Factors and parameters that played a significant role in the outcome, such as the number of layers in the neural network, were also evaluated.

scholarly journals Establishment of a Validation and Benchmark Database for the Assessment of Ship Operation in Adverse Conditions

2016 ◽  
Author(s):  
Florian Sprenger ◽  
Vahid Hassani ◽  
Adolfo Maron ◽  
Guillaume Delefortrie ◽  
Thibaut Van Zwijnsvoorde ◽  
...  
Keyword(s):  
Experimental Data ◽  
Shallow Water ◽  
Deep Water ◽  
Public Domain ◽  
Added Resistance ◽  
Test Program ◽  
Adverse Conditions ◽  
Research Institutes ◽  
Drift Force ◽  
Ship Operation

The Energy Efficiency Design Index (EEDI), introduced by the IMO [1] is applicable for various types of new-built ships since January 2013. Despite the release of an interim guideline [2], concerns regarding the sufficiency of propulsion power and steering devices to maintain manoeuvrability of ships in adverse conditions were raised. This was the motivation for the EU research project SHOPERA (Energy Efficient Safe SHip OPERAtion, 2013–2016 [3–6]). The aim of the project is the development of suitable methods, tools and guidelines to effectively address these concerns and to enable safe and green shipping. Within the framework of SHOPERA, a comprehensive test program consisting of more than 1,300 different model tests for three ship hulls of different geometry and hydrodynamic characteristics has been conducted by four of the leading European maritime experimental research institutes: MARINTEK, CEHIPAR, Flanders Hydraulics Research and Technische Universität Berlin. The hull types encompass two public domain designs, namely the KVLCC2 tanker (KRISO VLCC, developed by KRISO) and the DTC container ship (Duisburg Test Case, developed by Universität Duisburg-Essen) as well as a RoPax ferry design, which is a proprietary hull design of a member of the SHOPERA consortium. The tests have been distributed among the four research institutes to benefit from the unique possibilities of each facility and to gain added value by establishing data sets for the same hull model and test type at different under keel clearances (ukc). This publication presents the scope of the SHOPERA model test program for the two public domain hull models — the KVLCC2 and the DTC. The main particulars and loading conditions for the two vessels as well as the experimental setup is provided to support the interpretation of the examples of experimental data that are discussed. The focus lies on added resistance at moderate speed and drift force tests in high and steep regular head, following and oblique waves. These climates have been selected to check the applicability of numerical models in adverse wave conditions and to cover possible non-linear effects. The obtained test results with the KVLCC2 model in deep water at CEHIPAR are discussed and compared against the results obtained in shallow water at Flanders Hydraulics Research. The DTC model has been tested at MARINTEK in deep water and at Technische Universität Berlin and Flanders Hydraulics Research in intermediate/shallow water in different set-ups. Added resistance and drift force measurements from these facilities are discussed and compared. Examples of experimental data is also presented for manoeuvring in waves. At MARINTEK, turning circle and zig-zag tests have been performed with the DTC in regular waves. Parameters of variation are the initial heading, the wave period and height.

Head Wave Simulation of a KCS Model Using OpenFOAM for the Assessment of Sea-Margin

2022 ◽  
pp. 1-24
Author(s):  
Hafizul Islam ◽  
Carlos Guedes Soares
Keyword(s):  
Head Wave ◽  
Container Ship ◽  
Added Resistance ◽  
Free Condition ◽  
Wave Simulation ◽  
Calm Water ◽  
Sinkage And Trim ◽  
Simulation Results ◽  
Design Speed ◽  
Propulsion Power

Abstract The paper presents calm water and head wave simulation results for a KRISO Container Ship (KCS) model. All simulations have been performed using the open source CFD toolkit, OpenFOAM. Initially, a systematic verification study is presented using the ITTC guideline to assess the simulation associated uncertainties. After that, a validation study is performed to assess the accuracy of the results. Next, calm water simulations are performed with sinkage and trim free condition at varying speeds. Later, head wave simulations are performed with heave and pitch free motion. Simulations are repeated for varying wave lengths to assess the encountered added resistance by the ship in design speed. The results are validated against available experimental data. Finally, power predictions are made for both calm water and head wave cases to assess the required propulsion power. The paper tries to assess the validity of using 25% addition as sea margin over calm water prediction to consider wave encounters

Energy Efficient Safe Ship Operation (SHOPERA)

2015 ◽  
Author(s):  
Apostolos Papanikolaou ◽  
George Zaraphonitis ◽  
Elzbieta Bitner-Gregersen ◽  
Vladimir Shigunov ◽  
Ould El Moctar ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Assessment Procedure ◽  
Major Step ◽  
Ongoing Research ◽  
Method Of Calculation ◽  
Adverse Conditions ◽  
Energy Efficiency Design Index ◽  
Ship Operation ◽  
Propulsion Power ◽  
Engine Power

The 2012 guidelines on the method of calculation of the attained Energy Efficiency Design Index (EEDI) for new ships, MEPC.212(63), as updated by MEPC 245(66) in April 2014, represent a major step forward in implementing energy efficiency regulations for ships through the introduction of the EEDI limits for various types of ships. There are, however, serious concerns regarding the sufficiency of propulsion power and steering devices to maintain maneuverability of ships in adverse conditions, hence regarding the safety of ships, if the EEDI requirements are achieved by simply reducing the installed engine power. This was the rationale for a new EU funded research project with the acronym SHOPERA (2013-2016), aiming at developing suitable methods, tools and guidelines to effectively address the above concerns. The paper discusses the background of the ongoing research in project SHOPERA, presents early and intermediate results of the project and discusses certain fundamental issues regarding the formulation of proper criteria and practical assessment procedure for ship’s maneuverability and safety under adverse conditions.

Beam-radiation effects on wool in the ESEM

1986 ◽  
Vol 44 ◽  
pp. 674-675
Author(s):  
G.D. Danilatos
Keyword(s):  
Electron Beam ◽  
Radiation Effects ◽  
Research Work ◽  
Beam Radiation ◽  
Liquid Environment ◽  
Know How ◽  
Environmental Sem

The advent of the environmental SEM (ESEM) has made possible the examination of uncoated and untreated specimen surfaces in the presence of a gaseous or liquid environment. However, the question arises as to what degree the examined surface remains unaffected by the action of the electron beam. It is reasonable to assume that the beam invariably affects all specimens but the type and degree of effect may be totally unimportant for one class of applications and totally unacceptable for another; yet, for a third class, it is imperative to know how our observations are modified by the presence of the beam. The aim of this report is to create an awareness of the need to initiate research work in various fields in order to determine the guiding rules of the limitations (or even advantages) due to irradiation.

Computer programs for the calculation of x-ray intensities emitted by elements in multi-layer structures

1990 ◽  
Vol 48 (2) ◽  
pp. 216-217
Author(s):  
G.F. Bastin ◽  
H.J.M. Heijligers ◽  
J.M. Dijkstra
Keyword(s):  
Software Package ◽  
Light Element ◽  
Matrix Correction ◽  
Excellent Performance ◽  
Element Analysis ◽  
X Ray ◽  
Know How ◽  
Accurate Knowledge ◽  
Layer Structures ◽  
Bulk Matrix

For the calculation of X-ray intensities emitted by elements present in multi-layer systems it is vital to have an accurate knowledge of the x-ray ionization vs. mass-depth (ϕ(ρz)) curves as a function of accelerating voltage and atomic number of films and substrate. Once this knowledge is available the way is open to the analysis of thin films in which both the thicknesses as well as the compositions can usually be determined simultaneously.Our bulk matrix correction “PROZA” with its proven excellent performance for a wide variety of applications (e.g., ultra-light element analysis, extremes in accelerating voltage) has been used as the basis for the development of the software package discussed here. The PROZA program is based on our own modifications of the surface-centred Gaussian ϕ(ρz) model, originally introduced by Packwood and Brown. For its extension towards thin film applications it is required to know how the 4 Gaussian parameters α, β, γ and ϕ(o) for each element in each of the films are affected by the film thickness and the presence of other layers and the substrate.

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