scholarly journals Science of the 470 Sailing Performance

2020 ◽  
Vol 5 (01) ◽  
pp. 20-46
Author(s):  
Yutaka Masuyama ◽  
Munehiko Ogihara
Keyword(s):  
High Performance ◽  
World Wide ◽  
Academic Research ◽  
Research Community ◽  
Research Association ◽  
Velocity Prediction ◽  
Sailing Yacht ◽  
America’S Cup

This paper holds a significant place in the Journal of Sailing Technology, as the very last publication of Prof. Masuyama, published posthumously, and co-authors by Dr. Ogihara. For many decades, Prof. Masuyama has been a very influential and respected member of the sailing yacht research community world-wide, holding the chairmanship of the Sailing Yacht Research Association of Japan for close to 20 years, and being involved with the Japanese America’s Cup Challenge. His expertise and academic research have impacted generations of researchers, and his work on high performance sails, sailing yachts and velocity prediction remains at the forefront of sailing technology. It is therefore with great honour that the Journal of Sailing Technology presents the very last insights of Prof. Masuyama into the sailing performance of the 470 Olympic class dinghy.

Performance Prediction without Empiricism: A RANS-Based VPP and Design Optimization Capability

2007 ◽  
Author(s):  
Richard Korpus
Keyword(s):  
Design Optimization ◽  
Performance Prediction ◽  
Real World ◽  
Development Effort ◽  
New Approach ◽  
Flow Features ◽  
Velocity Prediction ◽  
Sailing Yacht ◽  
America’S Cup ◽  
Force Data

The use of Velocity Prediction Programs (VPP’s) in sailing yacht design has been standard practice for years. VPP fidelity, however, continues to be limited by the accuracy of aero and hydro force data used to represent a particular yacht. Even the most advanced America’s Cup VPP’s usually derive sail forces from panel or vortexlattice models, and hull forces from potential flow codes or experiment. Real world effects attributed to viscosity are added using simplified theoretical or empirical models that cannot resolve all the complexity of sailboat physics. This paper describes a new approach for performance prediction and design optimization that relies solely on high-resolution Reynolds-Averaged NavierStokes (RANS) computational fluid dynamics. All aero and hydro forces and moments are generated by RANS, and therefore include the real-world flow features of boundary layers, separation, shed vorticity, and turbulence. RANS software and grid model requirements suitable for VPP applications are discussed, and sample aero and hydro solutions included. Examples from America’s Cup design are used to demonstrate the technique’s practicality and accuracy. Finally, since VPP’s require forces from a large number of sailing conditions, the extensive development effort (undertaken through three America’s Cup cycles) to transition state-of-the-art RANS into the practical realm is summarized.

scholarly journals Recent Advances in Sailing Yacht Aerodynamics

2013 ◽  
Vol 65 (4) ◽  
Author(s):  
Ignazio Maria Viola
Keyword(s):  
High Performance ◽  
Three Dimensional ◽  
Optimization Techniques ◽  
Prediction Program ◽  
Research Areas ◽  
Recent Advances ◽  
Flow Device ◽  
Velocity Prediction ◽  
Sailing Yacht ◽  
Future Work

The analysis of sailing yacht aerodynamics has changed dramatically over the last 15 years and has enabled significant advances in performance prediction. For instance, the growth of computational fluid dynamics has significantly changed the way high-performance sails are designed. Three-dimensional mathematical models of fully rigged sail plans and the visualization of the turbulent unsteady flow pattern around them are now quite common, whereas ten years ago such a simulation would have been very rare and 20 years ago it would have been impossible. The parallel development of optimization techniques has resulted in new sail and yacht design methods. Changes in the experimental techniques have been as dramatic as in the numerical techniques. The introduction of the twisted flow device, the real-time velocity prediction program, and the most recent pressure measurements have allowed a step change in the potentialities of experimental sail aerodynamics. This paper aims to review the recent advances in sail aerodynamics and to highlight potential research areas for future work.

Getting out of the Field

2017 ◽  
Author(s):  
Jeasik Cho
Keyword(s):  
Qualitative Research ◽  
Academic Research ◽  
Scientific Research ◽  
Research Community

This chapter provides a review of the book, which explores how to conceptually understand and practically evaluate the quality of qualitative research. Despite the fact that there are few scholarly pieces regarding qualitative research, the depth and creativity that the pioneering researchers have demonstrated are profound, and the extent to which they cover not only the broad quality of qualitative research but also most of the specific qualities expected by many different kinds of qualitative research is incredible. This chapter summarizes the major topics of this book. Final remarks on this exciting, creative, but difficult topic are preceded by the following summary: Fortunately, There are commonly agreed, bold standards for evaluating the goodness of qualitative research in the academic research community. These standards are a part of what is generally called “scientific research.”

Evaluating Qualitative Research

2017 ◽  
Author(s):  
Jeasik Cho
Keyword(s):  
Qualitative Research ◽  
Large Scale ◽  
Academic Research ◽  
Research Community ◽  
Assessment Tools ◽  
Journal Articles ◽  
Journal Editors ◽  
The Past ◽  
Grant Proposals

This book provides the qualitative research community with some insight on how to evaluate the quality of qualitative research. This topic has gained little attention during the past few decades. We, qualitative researchers, read journal articles, serve on masters’ and doctoral committees, and also make decisions on whether conference proposals, manuscripts, or large-scale grant proposals should be accepted or rejected. It is assumed that various perspectives or criteria, depending on various paradigms, theories, or fields of discipline, have been used in assessing the quality of qualitative research. Nonetheless, until now, no textbook has been specifically devoted to exploring theories, practices, and reflections associated with the evaluation of qualitative research. This book constructs a typology of evaluating qualitative research, examines actual information from websites and qualitative journal editors, and reflects on some challenges that are currently encountered by the qualitative research community. Many different kinds of journals’ review guidelines and available assessment tools are collected and analyzed. Consequently, core criteria that stand out among these evaluation tools are presented. Readers are invited to join the author to confidently proclaim: “Fortunately, there are commonly agreed, bold standards for evaluating the goodness of qualitative research in the academic research community. These standards are a part of what is generally called ‘scientific research.’ ”

scholarly journals High Froude Number Experimental Investigation of the 2 DOF Behavior of a Multihull Float in Head Waves

2021 ◽  
Vol 6 (01) ◽  
pp. 1-20
Author(s):  
Paul Kerdraon ◽  
Boris Horel ◽  
Patrick Bot ◽  
Adrien Letourneur ◽  
David David Le Touzé
Keyword(s):  
High Performance ◽  
Good Representation ◽  
Prediction Program ◽  
Modeling Approach ◽  
Head Waves ◽  
Wide Range ◽  
Dynamic Velocity ◽  
Velocity Prediction ◽  
High Froude Number ◽  
Stability Issues

Dynamic Velocity Prediction Programs are taking an increasingly prominent role in high performance yacht design, as they allow to deal with seakeeping abilities and stability issues. Their validation is however often neglected for lack of time and data. This paper presents an experimental campaign carried out in the towing tank of the Ecole Centrale de Nantes, France, to validate the hull modeling in use in a previously presented Dynamic Velocity Prediction Program. Even though with foils, hulls are less frequently immersed, a reliable hull modeling is necessary to properly simulate the critical transient phases such as touchdowns and takeoffs. The model is a multihull float with a waterline length of 2.5 m. Measurements were made in head waves in both captive and semi-captive conditions (free to heave and pitch), with the model towed at constant yaw and speed. To get as close as possible to real sailing conditions, experiments were made at both zero and non-zero leeway angles, sweeping a wide range of speed values, with Froude numbers up to 1.2. Both linear and nonlinear wave conditions were studied in order to test the limits of the modeling approach, with wave steepness reaching up to 7% in captive conditions and 3.5% in semi-captive ones. The paper presents the design and methodology of the experiments, as well as comparisons of measured loads and motions with simulations. Loads are shown to be consistent, with a good representation of the sustained non-linearities. Pitch and heave motions depict an encouraging correlation which confirms that the modeling approach is valid.

Sailing Yacht Design Using Advanced Numerical Flow Techniques

1999 ◽  
Author(s):  
Mario Caponnetto ◽  
Alessandro Castelli ◽  
Philippe Dupont ◽  
Bernard Bonjour ◽  
Pierre-Louis Mathey ◽  
...  
Keyword(s):  
Computer Technology ◽  
Flow Simulation ◽  
Numerical Techniques ◽  
Flow Simulations ◽  
Competitive Edge ◽  
Numerical Flow Simulation ◽  
Sailing Yacht ◽  
America’S Cup ◽  
École Polytechnique ◽  
First Time

The 30th America's Cup will be held in New Zealand, commencing in October 1999. For the first time a Swiss team, the FAST2000 Challenge of the Club Nautique Morgien, will compete. Three laboratories of the EPFL (Ecole Polytechnique Federale de Lausanne) are collaborating with FAST2000 in the design of the boat that will race in the Cup challenges. Present-day design of IACC racing yachts relies on the use of numerical flow simulations to obtain a competitive edge. The computation of the complex hydrodynamic and aerodynamic flows around sailing yachts provides valuable information to supplement the more conventional empirical and experimental design techniques. Such flow simulations, however, are extremely challenging and thus often require state­of-the-art numerical techniques and computer technology. A number of the issues critical to IACC yacht design are discussed, and various approaches described to address them through the use of advanced numerical flow simulation.

Modeling IACC Sail Forces by Combining Measurements with CFD

1993 ◽  
Author(s):  
Jerome H. Milgram ◽  
Donald B. Peters ◽  
D. Noah Eckhouse
Keyword(s):  
Scale Model ◽  
Force Model ◽  
Actual Performance ◽  
Force Coefficients ◽  
Prediction Program ◽  
Induced Drag ◽  
Load Cells ◽  
Velocity Prediction ◽  
America’S Cup ◽  
Parasitic Components

A sailing dynamometer with a 42% scale model of an International America's Cup Class rig is used to measure sail forces and moments in actual sailing conditions. The sailing dynamometer is a 35-foot boat containing an internal frame connected to the hull by six load cells configured to measure all the forces and moments between the frame and the hull. All sailing rig components are attached to the frame, so that the sail forces are measured. Sail shapes in use are determined by computer-interfaced video. Computational fluid dynamics performed on the measured shapes provides the induced drag. This allows the measured drag to be decomposed into induced and form-and-parasitic components, which is necessary for generating a mathematical sail force model for a velocity prediction program (VPP). It is shown that VPP results using these new sail force coefficients are in better agreement with actual performance than are VPP results based on traditional sail force coefficients.

SPLASH Free-Surface Flow Code Methodology for Hydrodynamic Design and Analysis of IACC Yachts

1993 ◽  
Author(s):  
Bruce S. Rosen ◽  
Joseph P. Laiosa ◽  
Warren H. Davis ◽  
David Stavetski
Keyword(s):  
Free Surface ◽  
High Performance ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Surface Boundary ◽  
Induced Drag ◽  
Free Surface Boundary Condition ◽  
Surface Boundary Condition ◽  
America’S Cup ◽  
Areas Of Interest

A unique free-surface flow methodology and its application to design and analysis of IACC yachts are discussed. Numerical aspects of the inviscid panel code and details of the free-surface boundary condition are included, along with enhancements developed specifically for the '92 America's Cup defense. Extensive code validation using wind tunnel and towing tank experimental data address several areas of interest to the yacht designer. Lift and induced drag at zero Froude number are studied via a series of isolated fin/bulb/winglet appendages. An isolated surface piercing foil is used to evaluate simple lift/free­surface interactions. For complete IACC yacht models, upright wave resistance is investigated, as well as lift and induced drag at heel and yaw. The excellent correlation obtained for these cases demonstrates the value of this linear free-surface methodology for use in designing high performance sailing yachts.

Privacy Issues in the Web Services Architecture

2011 ◽  
pp. 29-55
Author(s):  
Barbara Carminati ◽  
Elena Ferrari ◽  
Patrick C.K. Hung
Keyword(s):  
Web Services ◽  
Web Service ◽  
Privacy Protection ◽  
World Wide ◽  
Research Community ◽  
Privacy Requirements ◽  
The World ◽  
Multiple Domains ◽  
Privacy Issues ◽  
The Web

A Web service is a software system that supports interoperable application-to-application interactions over a network. Web services are based on a set of XML standards such as Universal Description, Discovery and Integration (UDDI), Web Services Description Language (WSDL), and Simple Object Access Protocol (SOAP). Recently, there have been increasing demands and discussions about Web services privacy technologies in the industry and research community. To enable privacy protection for Web service consumers across multiple domains and services, the World Wide Web Consortium (W3C) published a document called “Web Services Architecture (WSA) Requirements” that defines some fundamental privacy requirements for Web services. However, no comprehensive solutions to the various privacy issues have been so far defined. For these reasons, this chapter will focus on privacy technologies by first discussing the main privacy issues in WSA and related protocols. Then, this chapter illustrates the standardization efforts going on in the context of privacy for Web services and proposes different technical approaches to tackle the privacy issues.

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