Relative Performance of Conventional Versus Movable-Ballast Racing Yachts

2005 ◽  
Author(s):  
Frank DeBord ◽  
Harry Dunning
Keyword(s):  
Physical Model ◽  
Morning Glory ◽  
Cfd Analysis ◽  
Design Issues ◽  
Design Features ◽  
Prediction Program ◽  
The Past ◽  
Trade Offs ◽  
Physical Model Tests ◽  
Velocity Prediction

Over the past few years several advanced concepts have gained wider acceptance from owners of large racing yachts and organizers of major international events. Two of these concepts, water ballast and canting keels, were evaluated during the design of the maxZ86 yachts Pyewacket and Morning Glory. This paper presents the key design features of these large movable ballast racing yachts and compares their performance to conventional racing yachts of similar size. Comparisons include results of physical model tests, CFD analysis using a panel code, velocity prediction program modeling, and sailing data from the existing boats. These results are accompanied by physical explanations of the differences, and the special testing and analysis requirements for the movable-ballast configurations are detailed. Finally, some of the design issues unique to the movable-ballast concepts and design trade-offs are discussed.

Approximation of the Calm Water Resistance on a Sailing Yacht Based on the 'Delft Systematic Yacht Hull Series'

1999 ◽  
Author(s):  
J. A. Kenning ◽  
U. B. Sonnenberg
Keyword(s):  
Water Resistance ◽  
Force Production ◽  
Data Set ◽  
Side Force ◽  
Prediction Program ◽  
Resistance Increase ◽  
The Past ◽  
Calm Water ◽  
Velocity Prediction ◽  
Sailing Yacht

Over the past years a considerable extension has been given to the Delft Systematic Yacht Hull Series (DSYHS) The DSYHS data set now contains information about both the bare hull and appended hull resistance in the upright and the heeled condition, the resistance increase due to the longitudinal trimming moment of the sails, the side force production and induced resistance due to side force at various combinations of forward speeds, leeway angles and heeling angles. New formulations for the relevant hydrodynamic forces as function of the hull geometry parameters have been derived to be able to deal with a larger variety of yacht hull shapes and appendage designs. During the past two years some results of this research have already been published. In the present paper an almost complete picture of the relevant expressions which may be used in a Velocity Prediction Program (VPP) will be presented.

scholarly journals Blockchain Consensus: An Overview of Alternative Protocols

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1363
Author(s):  
Damilare Peter Oyinloye ◽  
Je Sen Teh ◽  
Norziana Jamil ◽  
Moatsum Alawida
Keyword(s):  
Energy Consumption ◽  
State Of The Art ◽  
Hash Functions ◽  
The State ◽  
Design Features ◽  
The Past ◽  
Trade Offs ◽  
Overall Performance ◽  
And Performance ◽  
Made In

Blockchain networks are based on cryptographic notions that include asymmetric-key encryption, hash functions and consensus protocols. Despite their popularity, mainstream protocols, such as Proof of Work or Proof of Stake still have drawbacks. Efforts to enhance these protocols led to the birth of alternative consensus protocols, catering to specific areas, such as medicine or transportation. These protocols remain relatively unknown despite having unique merits worth investigating. Although past reviews have been published on popular blockchain consensus protocols, they do not include most of these lesser-known protocols. Highlighting these alternative consensus protocols contributes toward the advancement of the state of the art, as they have design features that may be useful to academics, blockchain practitioners and researchers. In this paper, we bridge this gap by providing an overview of alternative consensus protocols proposed within the past 3 years. We evaluate their overall performance based on metrics such as throughput, scalability, security, energy consumption, and finality. In our review, we examine the trade-offs that these consensus protocols have made in their attempts to optimize scalability and performance. To the best of our knowledge, this is the first paper that focuses on these alternative protocols, highlighting their unique features that can be used to develop future consensus protocols.

The Effects of Streamlined Rigging on Sailboat Performance

2011 ◽  
Author(s):  
Bruce J. Martin ◽  
Grzegorz P. Filip ◽  
Kevin J. Maki ◽  
Robert F. Beck ◽  
Eric Hall
Keyword(s):  
Cross Section ◽  
Circular Section ◽  
Prediction Program ◽  
The Past ◽  
Performance Change ◽  
Physical Experiments ◽  
Vortex Induced Vibrations ◽  
Velocity Prediction ◽  
Sailing Yacht ◽  
Time Required

The design of sailboat rigging influences the yacht’s performance through the change in vertical center of gravity, windage, and ability to control the shape of the rig. In the past, designers have attempted to minimize this drag through the use of streamlined shapes, because it is well known that a streamlined section has much less drag with respect to a circular shape. Streamlined shapes have not been commonly used in practice probably because they are difficult and costly to manufacture. Also, some shapes may exhibit worse vortex induced vibrations (VIV) when compared to circular rigging. New manufacturing capabilities using composite materials have suggested that streamlined shapes be reconsidered for yacht standing rigging. This paper investigates the influence of two cross-section shapes of the rigging on the performance of an IMS40 sailing yacht. A modified NACA foil and a circular section are selected for the comparison, and both shapes are analyzed with numerical simulations and physical experiments. We study the change in sailboat performance due to the different aerodynamic and material properties of the rigging. A velocity prediction program (VPP) is used to quantify the performance change by comparing the time required to sail two different race courses.

Introduction to biometric measures for Games User Research

2018 ◽  
Author(s):  
Lennart E. Nacke
Keyword(s):  
Physiological Data ◽  
Biometric Data ◽  
User Research ◽  
Academic Practice ◽  
The Past ◽  
Informed Decisions ◽  
Trade Offs ◽  
Research Questions ◽  
Industry Professionals

This chapter presents the physiological metrics used in Games User Research (GUR). Aimed at GUR professionals in the games industry, it explains what methods are available to researchers to measure biometric data while subjects are engaged in play. It sets out when it is appropriate to use biometric measures in GUR projects, the kind of data generated, and the differing ways it can be analysed. The chapter also discusses the trade-offs required when interpreting physiological data, and will help games researchers to make informed decisions about which research questions can benefit from biometric methodologies. As the equipment needed to collect biometric data becomes more sophisticated as well as cheaper, physiological testing of players during a game’s development will become more common. At the same time, Games User Researchers will become more discriminating in its use. Where in the past professionals in the games industry have used biometric testing to generate quick, actionable feedback about player responses to elements of a game, and have been less concerned with the scientific robustness of their methodology, as GUR develops a new breed of games industry professionals are attempting to deploy good academic practice in their researches.

The Application of VPPs to Practical Sailing Problems

1987 ◽  
Author(s):  
Kart L. Kirkman
Keyword(s):  
Prediction Program ◽  
Widespread Acceptance ◽  
Velocity Prediction ◽  
Do So

The velocity prediction program, VPP, appeared on the yachting scene about ten years ago and it now dominates design and sailing. Originally implemented as a handicapping tool under the Measurement Handicap System, now accepted internationally as IMS, it has seen widespread acceptance for many other uses, from design to tuning and racing. This capability means that it is productive, even necessary, for the typical sailor interested in good performance to understand how to apply a VPP to his activities. To do so requires an appreciation of how a VPP functions and how it is applied to practical sailing problems, such as sail selection or tactics. The paper presents a review of VPP fundamentals and then treats the following applications: - Sail selection and strategy for offshore yachts. - Tuning and optimization of all boats. It is the goal of the paper to impart a working understand­ing of the VPP to many sailors so that they can take advantage of the technology in their normal activities.

Added Resistance in Seaways and its Impact on Yacht Performance

2007 ◽  
Author(s):  
Kai Graf ◽  
Marcus Pelz ◽  
Volker Bertram ◽  
H. Söding
Keyword(s):  
Strong Impact ◽  
Wave Spectra ◽  
Linear Extensions ◽  
Added Resistance ◽  
Optimum Length ◽  
Prediction Program ◽  
Strip Theory ◽  
Velocity Prediction ◽  
Added Resistance In Waves ◽  
Response Amplitude Operators

A method for the prediction of seakeeping behaviour of sailing yachts has been developed. It is based on linear strip theory with some non-linear extensions. The method is capable to take into account heeling and yawing yacht hulls, yacht appendages and sails. The yacht's response amplitude operators (RAO) and added resistance in waves can be predicted for harmonic waves as well as for natural wave spectra. The method is used to study added resistance in seaways for ACC-V5 yachts of varying beam. Results are used for further VPP investigations. The AVPP velocity prediction program is used to study optimum length to beam ratio of the yachts depending on wind velocity and upwind to downwind weighting. This investigation is carried out for flat water conditions as well as for two typical wave spectra. The results show that taking into account added resistance in seaways has a strong impact on predicted performance of the yacht.

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