Hydrodynamics of high speed marine vehicles

2004 ◽  
pp. 3-13 ◽  
Author(s):  
O Faltinsen
Keyword(s):  
High Speed ◽  
Marine Vehicles

AERODYNAMIC LIFT FORCES ON MULTIHULLED MARINE VEHICLES

2021 ◽  
Vol 152 (A2) ◽  
Author(s):  
A G W Williams ◽  
M Collu ◽  
M H Patel
Keyword(s):  
High Speed ◽  
Vehicle Stability ◽  
Aerodynamic Design ◽  
Forward Motion ◽  
Marine Vehicles ◽  
Marine Transport ◽  
Stability Model ◽  
Lift Forces ◽  
High Payload ◽  
Aerodynamic Lift

The need for high-speed high-payload craft has led to considerable efforts within the marine transport industry towards a vehicle capable of bridging the gap between conventional ships and aircraft. One such concept uses the forward motion of the craft to create aerodynamic lift forces on a wing-like superstructure and hence, reduce the displacement and skin friction. This paper addresses the specific aerodynamic design of multihull for optimal lift production and shows that significant efficiency can be achieved through careful shaping of a ducted hull, with lift-to-drag ratios of nearly 50 for a complete aerodynamic hull configuration. Further analysis is carried out using a hybrid vehicle stability model to determine the effect of such aerodynamic alleviation on a theoretical planing hull. It is found that the resistance can be halved for a fifty metre, three hundred tonne vehicle with aerodynamic alleviation travelling at 70 knots. Results are presented for a candidate vessel.

Comparative Assessment of Rule-Based Design on the Pressures and Resulting Scantlings of High Speed Powercrafts

2020 ◽  
Author(s):  
Jean-Baptiste R.G. Souppez ◽  
Ermina Begovic ◽  
Pradeep Sensharma ◽  
Fuhua Wang ◽  
Anders Rosén
Keyword(s):  
High Speed ◽  
Future Trends ◽  
Rule Based ◽  
Marine Vehicles ◽  
Current State ◽  
Regulatory Bodies ◽  
1960S And 1970S ◽  
The 1960S ◽  
Design Case Study

The rules and regulations inherent to the design pressures and scantlings of high-speed powercrafts are numerous, and regularly reviewed. Recently, the new ISO 12215-5:2019 made notable changes to the way high-speed crafts are analysed, including extending the acceleration experienced up to 8 g in certain circumstances. Nevertheless, despite the multiple iterations and variety of regulatory bodies, the seminal work undertaken on planing crafts throughout the 1960s and 1970s remains the foundation of any rule-based design requirement. Consequently, this paper investigates an array of recently published rules though a comparative design case study, the current state-of-the-art across a number of regulations, and the ultimate impact on scantlings. The study reveals that, despite divergence in intermediate calculations and assumptions, similar requirements are ultimately achieved. Eventually, discussion on the comparison undertaken and future trends in high-speed marine vehicles is provided, tackling the relevance of classical planing theory in light of contemporary innovations.

scholarly journals Review of the Design and Technology Challenges of Zero-Emission, Battery-Driven Fast Marine Vehicles

2020 ◽  
Vol 8 (11) ◽  
pp. 941
Author(s):  
Apostolos D. Papanikolaou
Keyword(s):  
High Speed ◽  
Ship Design ◽  
Design And Technology ◽  
Marine Vehicles ◽  
Battery Capacity ◽  
Critical Issues ◽  
Safety Constraints ◽  
Funded Project ◽  
Zero Emission ◽  
The Eu

The paper deals with a critical review of unique problems and challenges related to the design and technology of zero-emission, battery driven, fast marine vehicles. The uniqueness of the ensuing ship design problem is the request to fit maximum battery capacity and to ensure minimum required power in order to achieve the set operational requirements for high service speed and sufficient range. The high-speed requirement is inherently connected with the request for minimum structural and lightship weight, while the design needs also to comply with set regulatory safety constraints. The underlying research is in the frame of the EU funded project TrAM (Transport: Advanced and Modular) and leads to the development and construction of a physical demonstrator for operation in the Stavanger area in Norway. The paper discusses the incurring critical issues, discusses the feasibility of the concept and concludes on the way ahead.

EXPERIENCE OF USING THE HARDWARE PLATFORM GRIFON TO SOLVE ACOUSTICAL PROBLEMS

2018 ◽  
pp. 63-69
Author(s):  
G. G. Alekseev ◽  
E. A. Alekseeva ◽  
P. V. Galagan ◽  
A. P. Sorokin ◽  
S. A. Sorokin
Keyword(s):  
High Speed ◽  
Heterogeneous Computing ◽  
Sound Propagation ◽  
Computer Hardware ◽  
Statistical Efficiency ◽  
Hardware Platform ◽  
Computing Platform ◽  
Marine Vehicles ◽  
Urgent Task ◽  
Minimal Mass

The creation of a set of computer hardware, associated with the common management and use of system-wide resources and software designed to handle hydroacoustic information is an urgent task. This is due to the further improvement of the characteristics of newly developed marine vehicles and systems. The article deals with the use of elements of the high-speed heterogeneous computing platform Griffon in the construction of specialized computing systems and the implementation of algorithms for processing hydroacoustic information. Potential capabilities of the equipment are discussed, demonstrating the prospects of creating computers based on the Griffon hardware platform with high parameters and minimal mass-size characteristics. The article proposes variants of algorithms specially designed for increasing the statistical efficiency and processing taking into account the influence of the sound propagation medium. The comparative characteristics and capabilities of the Griffon platform for creating various special computers for both stationary and mobile, including autonomous, hydroacoustic computer systems are presented.

Pure Yaw Simulations of Fast Delft Catamaran 372 in Deep Water

2020 ◽  
Author(s):  
Suleyman Duman ◽  
Sakir Bal
Keyword(s):  
Deep Water ◽  
High Speed ◽  
Point Of View ◽  
Hydrodynamic Performance ◽  
Marine Vehicles ◽  
Wave Interference ◽  
Force Moment ◽  
Unsteady Rans ◽  
Cfd Method ◽  
Turbulent Flow Conditions

Fast marine vehicles have become more important than ever before due to increasing need and population. In maritime sector, special ship types such as catamaran and trimaran have already been designed and/or built to the civil and naval areas of use. The hydrodynamic performance of these vessels is an interesting problem for naval architects due to the wave interference between the hulls. From this point of view, a generic high-speed catamaran hull form (Delft catamaran 372 or DC372) has been chosen for the numerical prediction of manoeuvring coefficients. To achieve this, the pure yaw captive manoeuvre simulations of the DC372 have been performed in deep water conditions at several oscillating frequencies by using CFD method. The unsteady RANS equations have been solved under incompressible, viscous and fully turbulent flow conditions. The uncertainty in the computations has been determined using proper techniques. Manoeuvring coefficients have been calculated by processing time dependent force/moment signals obtained numerically with the help of Fourier analysis. Due to the accurate grid structure used here, numerical ventilation has been prevented and wave deformations have been captured well.

Ship Hull Drag Reduction Using Bottom Air Injection

2007 ◽  
Author(s):  
Ahmad Fakhraee ◽  
Manoucher Rad ◽  
Hamid Amini ◽  
Mehdi Rishehri
Keyword(s):  
Drag Reduction ◽  
High Speed ◽  
Frictional Resistance ◽  
Air Injection ◽  
Hydrodynamic Resistance ◽  
Alternative Form ◽  
Hydrodynamic Characteristics ◽  
Air Cavity ◽  
Marine Vehicles ◽  
Wetted Surface Area

Air cavity ship concept has received some interest due to its potential on viscous resistance reduction for high speed craft. Air-cavity ships (ACS) are advanced marine vehicles that use air injection at the wetted hull surfaces to improve a vessel’s hydrodynamic characteristics. Air is supplied through nozzles under a profiled bottom to generate an air cavity beneath such a ship, so that a steady air layer separates a part of the bottom from contact with water, consequently reducing hydrodynamic resistance. Resistance tests were conducted with two forms: first of which was planning catamaran hull form, and second one was an alternative form with an air cavity injection under its bottom which was tested both without any air injection and with three different air injection ranges. Dead rise angle was fixed to 23 degree during both model tests. Frictional resistance was calculated from wetted surface area and compared with total resistance. It is clear from these results that improvements in high speed planning catamarans can be realized by using bottom air injection. Drag reduction achieved on these model is within 13–23 percent.

scholarly journals Lift-to-Drag Ratio of the Application of Hydrofoil With Variation Mounted Position on High-Speed Patrol Vessel

CFD letters ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1-9
Author(s):  
Muhammad Arif Budiyanto ◽  
Naufal Yudha Prawira ◽  
Haekal Dwiputra
Keyword(s):  
High Speed ◽  
High Performance ◽  
Hydrodynamic Performance ◽  
Comparison Result ◽  
Academic Literature ◽  
Marine Vehicles ◽  
Basic Model ◽  
Optimum Position ◽  
Drag Ratio ◽  
Lift To Drag Ratio

The hydrofoil is one of the hydrodynamic support technologies for marine vehicles that provide a high performance and are feasible to operate. The mounting position of hydrofoils on the hull is one of the keys to improving the hydrodynamic performance, where the existing academic literature to find the optimum position of hydrodynamic is still deficient. The objective of this study is to compare the mounting locations of hydrofoil in the horizontal axis in a high-speed patrol vessel. The comparison result is based on the computational fluid dynamics where the basic model was validated using experimental data. Three mounting location cases of hydrofoils were performed i.e. middle section, stern section, and behind the stern. The result shows that the optimal hydrofoil mounting position is after the transom. In this position, the value of the lift-to-drag ratio is higher by an average of 10% - 29% compared to other positions depending on the speed of the ship.

STATIC STABILITY OF AERODYNAMICALLY SUPPORTED PLATFORMS MOVING ABOVE WATER

2021 ◽  
Vol 153 (A3) ◽  
Author(s):  
K I Matveev
Keyword(s):  
High Speed ◽  
Stability Margin ◽  
Ground Effect ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Underlying Surface ◽  
Geometrical Parameters ◽  
Marine Vehicles ◽  
Effect Theory ◽  
Rigid Plane

The motion stability is the most important problem of high-speed marine vehicles that utilize aerodynamic support. A simplified analysis and calculations of longitudinal static stability of several basic platforms moving above water are carried out in this study. The analysis is based on the extreme ground effect theory and the assumption of hydrostatic deformations of the water surface. Effects of the underlying surface type, Froude number, and several geometrical parameters on main aerodynamic characteristics, including the static stability margin, are presented. If the underlying surface is water instead of a rigid plane, the static stability worsens for platforms with flat or S-shaped lower surfaces, but it slightly improves for a horizontal platform with a flap. The static stability margin remains positive for S-shaped profiles at sufficiently low Froude numbers, while it is negative for other configurations.

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