Selecting a Keel Appendage for a Cruising Yacht From a Standard Keel Series

1979 ◽  
Author(s):  
Deborah W. Berman
Keyword(s):  
Aspect Ratio ◽  
Model Tests ◽  
Thickness Ratio ◽  
Model Data ◽  
Standard Series ◽  
Stevens Institute ◽  
Form Part ◽  
Institute Of Technology

The purpose of this paper is to describe the results of model tests for a series of three keels; two at constant draft; two at constant aspect ratio; all at constant taper ratio and thickness ratio. These keels form part of a standard series developed by Pierre De Saix at Davidson Laboratory, Stevens Institute of Technology in 1974 and originally tested on a 5.5 meter hull (1). The three keels were all tested on the model of a small cruising yacht over a range of heel angles, leeways and speeds. An analysis is made of the expanded model data and a comparison presented of the forces and moments operating on the deepest keel and the two keels of constant draft.

Seakeeping Evaluation of a Tri-SWACH Based on CFD Calculations and Model Tests

2021 ◽  
Author(s):  
Gong Xiang ◽  
Raju Datla ◽  
Xianbo Xiang
Keyword(s):  
Time Domain ◽  
High Speed ◽  
Three Dimensional ◽  
Primary Objective ◽  
Model Tests ◽  
Numerical Predictions ◽  
Seakeeping Performance ◽  
Stevens Institute ◽  
Transverse Stability ◽  
Institute Of Technology

AEGIR is a time-domain seakeeping CFD code that uses an advanced, high-order boundary element method (BEM) to solve the three-dimensional potential-flow and has been developed for several years. In this paper, the latest version of AEGIR is used to predict the seakeeping of the Tri-SWACH with and without side hulls in headsea regular waves respectively. The primary objective was to evaluate its accuracy of predicting seakeeping performance of the Tri-SWACH under regular headsea waves in AEGIR. A series of simulated time domain heave and pitch responses for Tri-SWACH with and without side hulls via AEGIR have been compared with corresponding model tests conducted in the high speed towing tank in Davidson Lab, Stevens Institute of Technology. A good agreement in terms of heave and pitch responses between AEGIR numerical predictions and experimental data shows the seakeeping prediction capability of AEGIR for Tri-SWACH Preliminary Design. Also, the simulated seakeeping of a Tri-SWACH is compared with a Tri-SWACH center hull. It is found that the effects of side hulls will increase the transverse stability of the Tri-SWACH without causing additional significant effect on the seakeeping performance of the Tri-SWACH.

Some Considerations on the Reaction of Wind Upon Sails

1938 ◽  
Vol 42 (334) ◽  
pp. 867-871 ◽  
Author(s):  
J. T. C. Moore-Brabazon
Keyword(s):  
New Jersey ◽  
Model Tests ◽  
Towing Tank ◽  
Stevens Institute ◽  
Institute Of Technology ◽  
General Configuration ◽  
Sailing Boat

The study of the problems connected with a successful racing sailing boat, like Gaul, can be divided into three parts. There is first of all the general configuration of the hull upon which lately much study has been directed. Anybody interested in this should look up the article, “Model Tests of Sailing Yachts,” by Kenneth S. M. Davidson, Director, Experimental Towing Tank, Stevens Institute of Technology, New Jersey, appearing in the August issue of “The Rudder,” in which it will be noted model hulls are pulled through the tank at an angle of heel, and with an angle of drift.

An Improved Undergraduate Human Factors Course: Three Results

1983 ◽  
Vol 27 (6) ◽  
pp. 455-458
Author(s):  
Richard Halstead-Nussloch ◽  
Mark C. Detweiler ◽  
M. Peter Jurkat ◽  
Elissa L.A. Hamilton ◽  
Leon S. Gold
Keyword(s):  
Human Factors ◽  
Experimental Methods ◽  
Design Solution ◽  
Course Enrollment ◽  
Stevens Institute ◽  
Computer Based ◽  
Institute Of Technology

The undergraduate human factors course was improved at the Stevens Institute of Technology. The objectives of the course improvement were twofold: 1) to increase the quality of the course, and 2) to increase enrollment. Computer-based modules were developed and implemented to achieve these objectives. Three primary findings emerged from their use. First, students finished the course with a firm grounding in the empirical and experimental methods of human factors. Second, students generated more design solution alternatives by using the modules. Third, course enrollment increased by seventy-five percent.

The Influences of Stagger and Pretwist Angles of Blades on Coupling Vibration in Shaft-Disk-Blade Systems

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Hassan Heydari ◽  
Amir Khorram ◽  
Laya Afzalipour
Keyword(s):  
Aspect Ratio ◽  
Natural Frequencies ◽  
Thickness Ratio ◽  
Lagrangian Approach ◽  
Coupling Vibration ◽  
Flexible Shaft ◽  
Blade Thickness ◽  
Out Of Plane ◽  
Coupling Pattern ◽  
Stagger Angle

Abstract The influences of stagger angle (α) and pretwist angle (βL) of blades on the coupling vibration among shaft bending and blade bending in a shaft-disk-blade (SDB) system are investigated using a Lagrangian approach in combination with the assumed modes method (AMM). The disk is rigid, and the flexible shaft is supported with two rigid bearings. It is shown that α and βL have variable effects on the coupling vibration because their influences can be increased, reduced, or even completely eliminated for different values of disk location (λ), blade thickness ratio (δ), and blade aspect ratio (γ). To study the coupling vibration in an SDB system, consideration of λ, δ, and γ are very important because those can alter the coupling magnitude, the coupling pattern as well as the predominant modes. Nevertheless, previous researches rarely take into account these parameters. Moreover, in the present work, to investigate the natural frequencies and critical speeds versus λ, δ, and γ, new diagrams are introduced. Also, the relation between the in-plane and out-of-plane motions of the blades with the coupling vibration is precisely analyzed.

On the Integration of Remote and Virtual Experiments Into a Comprehensive Student Laboratory Experience

2006 ◽  
Author(s):  
El-Sayed S. Aziz ◽  
Constantin Chassapis ◽  
Sven K. Esche
Keyword(s):  
Experimental System ◽  
Asynchronous Learning ◽  
Web Based ◽  
Educational Benefits ◽  
Laboratory Experience ◽  
Virtual Experiments ◽  
Laboratory Education ◽  
Stevens Institute ◽  
Student Laboratory ◽  
Institute Of Technology

Student laboratories have always played a key role in the engineering education at Stevens Institute of Technology (SIT). Recently, SIT has designed and implemented several innovative Web-based tools for engineering laboratory education and evaluated their learning effectiveness in pilot deployments in various engineering courses. These Web-based tools include both remotely operated experiments based on actual experimental devices as well as virtual experiments representing software simulations. These tools facilitate the development of learning environments, which - possibly in conjunction with traditional hands-on experiments - allow the expansion of the scope of the students' laboratory experience well beyond the confines of what would be feasible in the context of traditional laboratories. This becomes possible because of the scalability of resources that are shared through the Web and the flexibility of software simulations in varying the characteristic parameters of the experimental system under investigation. Further educational benefits of the proposed laboratory approach are that asynchronous learning modes are supported and discovery-based self-learning, of the students is promoted. This paper will present the details of the approach taken at SIT in integrating these Web-based tools into a comprehensive student laboratory experience. As an example for the implementation of such Web-based experiments, an Industrial-Emulator/Servo-Trainer System will be described, which is used at SIT in a junior-level course on mechanisms and machine dynamics.

Numerical Simulation on the Mechanical Performance of the Wind Generator Latticed Concrete-Filled Steel Tubular Tower

2014 ◽  
Vol 578-579 ◽  
pp. 751-756
Author(s):  
Bin Li ◽  
Qun Hui Zhang ◽  
Chun Yan Gao
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Bearing Capacity ◽  
Failure Mode ◽  
Mechanical Performance ◽  
Great Influence ◽  
Local Buckling ◽  
Ultimate Bearing Capacity ◽  
Thickness Ratio ◽  
Stiffness Ratio

Nonlinear finite element parameters analysis on the lattice type steel pipe concrete wind turbine tower, it shows the entire process of load bearing, failure mode and ultimate bearing capacity, researches on the influence law of aspect ratio, form of tower webs, tower diameter to thickness ratio and web member stiffness to tower column stiffness ratio on the ultimate bearing capacity and tower failure mode. The finite element analysis results shows that the tower aspect ratio λ, the diameter-thickness ratio γ of tower columns and the increase of stiffness ratio β between web members and tower columns has great influence on ultimate bearing capacity and failure mode, while the form of webs has small influence on that. with the increase of tower aspect ratio λ, the decrease of diameter-thickness ratio γ of tower columns and the increase of stiffness ratio β between web members and tower columns, the ultimate bearing capacity of this kind of latticed towers increase, the failure mode changed from Web local buckling to The combined damage of Web local buckling and the tension tower yield. This paper suggests that in the design of wind turbulent generator tower, the tower aspect ratio λ should be best controlled at 1/9, the bottom layers of this kind of tower should best use the re-divided web members, and other web member forms used on above layers, the diameter-thickness ratio γ of tower column should be taken less than 30, and the stiffness ratio β between webs and columns should be controlled less than 0.05 in order to avoid damage occurring on the tower columns earlier than the webs. The results can provide evidence for the engineering design.

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