scholarly journals NUMERICAL AND EXPERIMENTAL ASSESSMENT OF THE TOTAL RESISTANCE OF A YACHT

Brodogradnja ◽  
2021 ◽  
Vol 72 (3) ◽  
pp. 61-80
Author(s):  
Nastia Degiuli ◽  
◽  
Andrea Farkas ◽  
Ivana Martić ◽  
Ivan Zeman ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Design Process ◽  
Turbulence Models ◽  
Ship Design ◽  
Verification And Validation ◽  
Total Resistance ◽  
Experimental Assessment ◽  
Towing Tank ◽  
Bulbous Bow ◽  
The Impact

One of the main goals of the ship design process is the reduction of the total resistance, which is nowadays even more highlighted due to increasingly stringent rules related to ship energy efficiency. In this paper, the investigation of the impact of the bow on the total resistance of a yacht is carried out for three models by towing tank tests and numerical simulations. The verification and validation studies are performed, and satisfactory agreement is achieved. Also, a comparison of three turbulence models for the prediction of the total resistance of a yacht is made. The flow around the models of the yacht is analysed and it is demonstrated that bulbous bow causes the reduction of wave elevations. Experimental and numerical results indicate that the decrease in the total resistance due to bulbous bow can be up to 7%. Finally, the applicability of CFD within the ship design process is presented.

A COMPREHENSIVE APPROACH TO SURVIVABILITY ASSESSMENT IN NAVAL SHIP CONCEPT DESIGN

2021 ◽  
Vol 156 (A4) ◽  
Author(s):  
A S Piperakis ◽  
D J Andrews
Keyword(s):  
Design Process ◽  
Early Stage ◽  
Ship Design ◽  
Assessment Tools ◽  
Concept Design ◽  
Trade Offs ◽  
Assessment Approach ◽  
The Uk ◽  
Constituent Elements ◽  
The Impact

Alongside deploying weapons and sensors what makes a warship distinct is its survivability, being the measure that enables a warship to survive in a militarily hostile environment. The rising cost of warship procurement, coupled with declining defence budgets, has led to cost cutting, often aimed at aspects, such as survivability, which may be difficult to quantify in a manner that facilitates cost capability trade-offs. Therefore, to meet ever-reducing budgets, in real terms, innovation in both the design process and the design of individual ships is necessary, especially at the crucial early design stages. Computer technology can be utilised to exploit architecturally orientated preliminary design approaches, which have been conceived to explore innovation early in the ship design process and the impact of such issues as survivability. A number of survivability assessment tools currently exist; however, most fail to integrate all the constituent elements of survivability (i.e. susceptibility, vulnerability and recoverability), in that they are unable to balance between the component aspects of survivability. Some of these tools are qualitative and therefore less than ideal in specifying survivability requirements, others are aimed towards the more detailed design stages where implementing changes is heavily constrained or even impractical. This paper presents a survivability assessment approach combining various tools used by UCL and the UK Ministry of Defence, as well as a new approach for recoverability assessment. The proposed method attempts to better integrate and quantify survivability in early stage ship design, which is facilitated by the UCL derived, architecturally focused, design building block approach. The integrated survivability method is demonstrated for a set of naval combatant concept designs and for two replenishment ship studies to test the robustness of the proposed approach.

Factors Affecting Ship Design and Construction Lead Time and Cost

2005 ◽  
Vol 21 (03) ◽  
pp. 186-194
Author(s):  
Howard Moyst ◽  
Biman Das
Keyword(s):  
Design Process ◽  
Lead Time ◽  
Ship Design ◽  
Start Time ◽  
Design Quality ◽  
Improve Design ◽  
Design Changes ◽  
The Impact ◽  
Design And Construction

This paper reviews a ship design and construction case study in the context of the published literature on the design process and its impact on construction. The objective was to explore the factors that impact design and construction lead time and cost. Design and construction managers constantly experience pressure to accelerate the construction start time in an environment characteristic of frequent design changes and rework. Often the construction of the first ships of a series will aggressively overlap the design phase. This investigation assessed a case study that illustrated that as the degree of overlap between design and construction increases, design changes increased ship construction costs and duration. This negates the advantage of trying to reduce lead time by overlapping phases. Before strategies of overlapping are utilized, shipbuilders need to better understand the details of the design process and its integration with other functions to improve design quality and reduce the impact of design changes on manufacturing and construction. It is recommended that when overlapping strategies are considered, design changes and their impact on construction be factored into the decision. A better strategy would be to eliminate design quality issues and design and construction rework.

scholarly journals CHOOSING THE STYLE OF A NEW DESIGN - THE KEY SHIP DESIGN DECISION

2021 ◽  
Vol 160 (A1) ◽  
Author(s):  
D Andrews
Keyword(s):  
Design Process ◽  
Building Block ◽  
Early Stage ◽  
Ship Design ◽  
Design Decision ◽  
Design Issues ◽  
Design Study ◽  
Design Option ◽  
The Impact ◽  
Block Approach

As a former senior designer of naval vessels and, more recently, a leading researcher in ship design, the author has previously presented a description of the ship design process in terms of the important decisions a ship designer makes in concept exploration. Such decision are made consciously or unconsciously in order to produce a new design or, preferably, any design option. It has been contended in many publications that the first real decision that a ship designer makes, in order to proceed, is the selection of the “style” of the design study or of a specific design option. This term was adopted in order to cover, not just a host of design issues and standards implicit in a given study, but also, at this very initial step, the overall characteristics of any particular study. So the term style could be said to be doubly important. The current paper considers the nature of the early ship design process for complex multi-functional vessels and then retraces the origins of the particular use of the term, where it was seen as the last of the five elements in Brown and Andrews’ 1980 encapsulation of the ship design issues that matter to the naval architect, incorporated in the term “S to the 5th”. This leads on to consideration of the various aspects of design style, many of which could be considered “transversals” as they apply across the naval architectural sub-disciplines and to the component material sub-systems comprising a ship. One of the distinctive advantages of the architecturally driven ship synthesis or Design Building Block approach is that it can address many of these style issues in the earliest descriptions of an emergent design study. Examples, drawing on a range of built Royal Navy ship designs, are presented to show their top-level style characteristics, followed by a series of ship design research studies illustrating how the impact of specific component style aspects can be investigated in early stage ship design, using the UCL Design Building Block approach. Finally, recent research led investigations into integrating ship style into early stage ship design are summarized to demonstrate why the choice of “style” is seen to be The Key Ship Design Decision.

The Impact of Contracts on Ship Design Preparation

2012 ◽  
Vol 28 (02) ◽  
pp. 87-95
Author(s):  
Kenneth W. Fisher
Keyword(s):  
Design Process ◽  
Ship Design ◽  
Ship Construction ◽  
The Impact

The implementation of vessel designs is usually achieved through contracts for ship construction or conversion. Accordingly, the design process and the design organization's product have to anticipate and take into account the constraints and requirements of the contracts that control the use of the design, as well as the contract that initiates the design process. This paper addresses the most common contractual factors that have to be considered during preparation of ship designs.

scholarly journals Choosing the Style of a New Design - The Key Ship Design Decision

2018 ◽  
Vol Vol 160 (A1) ◽  
Author(s):  
D Andrews
Keyword(s):  
Design Process ◽  
Building Block ◽  
Early Stage ◽  
Ship Design ◽  
Design Decision ◽  
Design Issues ◽  
Design Study ◽  
Design Option ◽  
The Impact ◽  
Block Approach

As a former senior designer of naval vessels and, more recently, a leading researcher in ship design, the author has previously presented a description of the ship design process in terms of the important decisions a ship designer makes in concept exploration. Such decision are made consciously or unconsciously in order to produce a new design or, preferably, any design option. It has been contended in many publications that the first real decision that a ship designer makes, in order to proceed, is the selection of the “style” of the design study or of a specific design option. This term was adopted in order to cover, not just a host of design issues and standards implicit in a given study, but also, at this very initial step, the overall characteristics of any particular study. So the term style could be said to be doubly important. The current paper considers the nature of the early ship design process for complex multi-functional vessels and then retraces the origins of the particular use of the term, where it was seen as the last of the five elements in Brown and Andrews’ 1980 encapsulation of the ship design issues that matter to the naval architect, incorporated in the term “S to the 5th”. This leads on to consideration of the various aspects of design style, many of which could be considered “transversals” as they apply across the naval architectural sub-disciplines and to the component material sub-systems comprising a ship. One of the distinctive advantages of the architecturally driven ship synthesis or Design Building Block approach is that it can address many of these style issues in the earliest descriptions of an emergent design study. Examples, drawing on a range of built Royal Navy ship designs, are presented to show their top-level style characteristics, followed by a series of ship design research studies illustrating how the impact of specific component style aspects can be investigated in early stage ship design, using the UCL Design Building Block approach. Finally, recent research led investigations into integrating ship style into early stage ship design are summarized to demonstrate why the choice of “style” is seen to be The Key Ship Design Decision.

scholarly journals Impact of Passive Energy Efficiency Measures on Cooling Energy Demand in an Architectural Campus Building in Karachi, Pakistan

2021 ◽  
Vol 13 (13) ◽  
pp. 7251
Author(s):  
Mushk Bughio ◽  
Muhammad Shoaib Khan ◽  
Waqas Ahmed Mahar ◽  
Thorsten Schuetze
Keyword(s):  
Energy Efficiency ◽  
Energy Demand ◽  
Electricity Consumption ◽  
Information Modeling ◽  
Base Case ◽  
Energy Efficiency Measures ◽  
Efficiency Measures ◽  
The Impact ◽  
Cooling Energy Demand ◽  
Campus Building

Electric appliances for cooling and lighting are responsible for most of the increase in electricity consumption in Karachi, Pakistan. This study aims to investigate the impact of passive energy efficiency measures (PEEMs) on the potential reduction of indoor temperature and cooling energy demand of an architectural campus building (ACB) in Karachi, Pakistan. PEEMs focus on the building envelope’s design and construction, which is a key factor of influence on a building’s cooling energy demand. The existing architectural campus building was modeled using the building information modeling (BIM) software Autodesk Revit. Data related to the electricity consumption for cooling, building masses, occupancy conditions, utility bills, energy use intensity, as well as space types, were collected and analyzed to develop a virtual ACB model. The utility bill data were used to calibrate the DesignBuilder and EnergyPlus base case models of the existing ACB. The cooling energy demand was compared with different alternative building envelope compositions applied as PEEMs in the renovation of the existing exemplary ACB. Finally, cooling energy demand reduction potentials and the related potential electricity demand savings were determined. The quantification of the cooling energy demand facilitates the definition of the building’s electricity consumption benchmarks for cooling with specific technologies.

scholarly journals A review of challenges and benefits of integration of CHP plant into the grid: a case study in Serbia

2021 ◽  
Author(s):  
Rade M. Ciric ◽  
Sasa N. Mandic
Keyword(s):  
Energy Efficiency ◽  
Negative Impact ◽  
Renewable Energy Sources ◽  
Increase Energy Efficiency ◽  
High Voltage Supply ◽  
The Republic ◽  
Technical Solutions ◽  
The Impact

AbstractThe Republic of Serbia must make significant efforts to promote and exploit renewable energy sources and increase energy efficiency in all energy sectors to ensure energy security and economic competitiveness, reduce the negative impact on the environment from energy production and use, and contribute to global efforts to reduce greenhouse gases. Within the paper several issues of integration of recently realized CHP plant are introduced and discussed. Firstly, the legal and energy policy issues in the Republic of Serbia regarding connecting CHP to the grid are presented. The challenges and technical solutions for CHP connection to the grid, as well as power quality issues and the role of the CHP plant during the restoration of power supply during the maintenance of the substation and unplanned loss of high voltage supply, are presented and discussed. Finally, the impact of prospective massive integration of CHP on the energy balance and CO2 emission reduction in the province of Vojvodina in Serbia is investigated and discussed. Since it is the first CHP plant realized in Serbia, it is crucial that experience be shared to all potential stakeholders in the future energy efficiency projects.

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