scholarly journals Experimental study of hydrodynamic forces acting on ship bow during wave capture

2019 ◽  
pp. 146-152
Author(s):  
Pavel Burakovskiy
Keyword(s):  
Experimental Study ◽  
Test Data ◽  
Model Test ◽  
Hydrodynamic Forces ◽  
Hydrodynamic Loads ◽  
Test Tank ◽  
Head Waves ◽  
Negative Effect

This paper studies behavior of ship in head waves, when her bow dips under water, which leads to hydrodynamic forces and moments to be assessed. This paper presents model test data obtained in the test tank on the model of ship bow (hydrodynamic loads on forecastle deck during wave capture) as well as updates the coefficient of flow around the bow. The study also shows that bulwark has negative effect upon safety in these conditions because it significantly increases hydrodynamic loads on the deck.

Experimental Study on Inner Reinforced Concrete-Block Composite Shaft Lining

2010 ◽  
Vol 163-167 ◽  
pp. 1316-1320
Author(s):  
Hao Liang Jiang ◽  
Ri Hui Liu
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Test Data ◽  
Model Test ◽  
Deformation Characteristic ◽  
Concrete Block ◽  
Vertical Shaft ◽  
Composite Shaft ◽  
Shaft Sinking ◽  
Shaft Lining

Inner reinforced concrete-block composite shaft lining was widely used in vertical shaft sinking by vertical shaft sinking machine (VSM) and freezing shaft. In this paper, the deformation characteristic, failure Patten and the load Bering capacity of inner reinforced concrete-block composite shaft lining are presented ,based on the model test .and the test data are provide for the design and calculation of this kinds of composite shaft lining.

Joint High Speed Sealift (JHSS) Segmented Model Test Data Analysis and Validation of Numerical Simulations

2012 ◽  
Author(s):  
Dominic Piro ◽  
Kyle A. Brucker ◽  
Thomas T. O'Shea ◽  
Donald Wyatt ◽  
Douglas Dommermuth ◽  
...  
Keyword(s):  
Data Analysis ◽  
Numerical Simulations ◽  
Test Data ◽  
Model Test ◽  
High Speed ◽  
Segmented Model

Effects of ball properties on throwing in young team-handball beginners

2021 ◽  
pp. 174795412110236
Author(s):  
Frowin Fasold ◽  
Benjamin Noël ◽  
André Nicklas ◽  
Fabian Lukac ◽  
Stefanie Klatt
Keyword(s):  
Experimental Study ◽  
Movement Patterns ◽  
Team Handball ◽  
Throwing Accuracy ◽  
Different Types ◽  
Negative Effect ◽  
Study Participants

Throwing a ball is a primary skill in team-handball and can be directly influenced by the properties of different types of balls. Therefore, the use of different balls (i.e., methodic ball) recommended by the handball federations (e.g., IHF) and the education guidelines, are important in teaching throwing. Previous studies have shown that movement patterns and throwing velocity can be influenced by different ball types and sizes. However, the influence of these factors on throwing accuracy has not been investigated in detail yet. This study aims to replicate the findings of previous studies on increasing throwing velocity in children by comparing the use of a soft methodic ball with a size 0 handball. Furthermore, this study investigates the influence of these balls on throwing accuracy. In an experimental study, participants (10-years of age) threw a soft methodic ball and a size 0 ball at target areas in a handball goal. For all the throws, throwing velocity and accuracy were measured. Commensurate with previous research, throwing velocity was higher for the soft methodic ball compared to a size 0 ball. No difference was found in accuracy, although, it is worth mentioning that the participants were only experienced in throwing using the size 0 ball. Moreover, only one-third of the children favored throwing with a size 0 ball, which is what they are used to in training and competition. The results of our study, therefore, confirm that using soft methodic balls additionally, positively influences the throwing velocity and has no negative effect on the accuracy in throwing among young handball beginners.

Guidelines for CFD Simulations of Spar VIM

2013 ◽  
Author(s):  
Charles Lefevre ◽  
Yiannis Constantinides ◽  
Jang Whan Kim ◽  
Mike Henneke ◽  
Robert Gordon ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Test Data ◽  
Model Test ◽  
Model Tests ◽  
Full Scale ◽  
Mooring System ◽  
Time Step ◽  
Cfd Simulations ◽  
Scaled Model ◽  
Sway Motion

Vortex-Induced Motion (VIM), which occurs as a consequence of exposure to strong current such as Loop Current eddies in the Gulf of Mexico, is one of the critical factors in the design of the mooring and riser systems for deepwater offshore structures such as Spars and multi-column Deep Draft Floaters (DDFs). The VIM response can have a significant impact on the fatigue life of mooring and riser components. In particular, Steel Catenary Risers (SCRs) suspended from the floater can be sensitive to VIM-induced fatigue at their mudline touchdown points. Industry currently relies on scaled model testing to determine VIM for design. However, scaled model tests are limited in their ability to represent VIM for the full scale structure since they are generally not able to represent the full scale Reynolds number and also cannot fully represent waves effects, nonlinear mooring system behavior or sheared and unsteady currents. The use of Computational Fluid Dynamics (CFD) to simulate VIM can more realistically represent the full scale Reynolds number, waves effects, mooring system, and ocean currents than scaled physical model tests. This paper describes a set of VIM CFD simulations for a Spar hard tank with appurtenances and their comparison against a high quality scaled model test. The test data showed considerable sensitivity to heading angle relative to the incident flow as well as to reduced velocity. The simulated VIM-induced sway motion was compared against the model test data for different reduced velocities (Vm) and Spar headings. Agreement between CFD and model test VIM-induced sway motion was within 9% over the full range of Vm and headings. Use of the Improved Delayed Detached Eddy Simulation (IDDES, Shur et al 2008) turbulence model gives the best agreement with the model test measurements. Guidelines are provided for meshing and time step/solver setting selection.

A Joint-Industry Effort to Develop and Verify CFD Modeling Practice for Vortex-Induced Motion of a Deep-Draft Semi-Submersible

2021 ◽  
Author(s):  
Hyunchul Jang ◽  
Dae-Hyun Kim ◽  
Madhusuden Agrawal ◽  
Sebastien Loubeyre ◽  
Dongwhan Lee ◽  
...  
Keyword(s):  
Test Data ◽  
Model Test ◽  
Working Group ◽  
Cfd Modeling ◽  
Physical Model Test ◽  
Mooring Lines ◽  
Cfd Models ◽  
Induced Motion ◽  
Modeling Practice ◽  
Decay Tests

Abstract Platform Vortex Induced Motion (VIM) is an important cause of fatigue damage on risers and mooring lines connected to deep-draft semi-submersible floating platforms. The VIM design criteria have been typically obtained from towing tank model testing. Recently, computational fluid dynamics (CFD) analysis has been used to assess the VIM response and to augment the understanding of physical model test results. A joint industry effort has been conducted for developing and verifying a CFD modeling practice for the semi-submersible VIM through a working group of the Reproducible Offshore CFD JIP. The objectives of the working group are to write a CFD modeling practice document based on existing practices validated for model test data, and to verify the written practice by blind calculations with five CFD practitioners acting as verifiers. This paper presents the working group’s verification process, consisting of two stages. In the initial verification stage, the verifiers independently performed free-decay tests for 3-DOF motions (surge, sway, yaw) to check if the mechanical system in the CFD model is the same as in the benchmark test. Additionally, VIM simulations were conducted at two current headings with a reduced velocity within the lock-in range, where large sway motion responses are expected,. In the final verification stage, the verifiers performed a complete set of test cases with small revisions of their CFD models based on the results from the initial verification. The VIM responses from these blind calculations are presented, showing close agreement with the model test data.

‘Asymmetric revelation’ effect: The influence of an increased number of photos on mental imagery and behavioural responses depending on target market

2018 ◽  
Vol 33 (3) ◽  
pp. 31-60
Author(s):  
Fabrice Larceneux ◽  
Marjolaine Bezançon ◽  
Thomas Lefebvre
Keyword(s):  
Experimental Study ◽  
Real Estate ◽  
Field Study ◽  
Mental Imagery ◽  
Target Market ◽  
Property Market ◽  
Lower Range ◽  
Revelation Effect ◽  
Behavioural Responses ◽  
Negative Effect

There has been little research exploring the effect of the number of photographs used to present a product, and the studies that have been carried out relate to experiments with a reduced number of non-informative photos. This article provides a first field study conducted on 3,658 real estate ads and shows that an increase in the number of photos decreases favourable behavioural responses for lower range properties, but has no effect in the case of higher range properties. This result is replicated and explained in an experimental study: for lower range properties, the addition of photos deteriorates the valence of mental images, decreases mental self-imagery and increases perceived worry. These variables explain the negative effect of the number of photos on behavioural responses. However, for higher range properties, the addition of photos – informative or not – does not improve behavioural responses. This ‘asymmetric revelation’ effect depending on the segment of the property market being targeted is discussed.

Analysis of Turam model test data

1971 ◽  
Vol 9 (2-3) ◽  
pp. 160
Author(s):  
J.P. Williams
Keyword(s):  
Test Data ◽  
Model Test

The Choice of the Propeller

1966 ◽  
Vol 3 (02) ◽  
pp. 158-171
Author(s):  
J. D. van Manen
Keyword(s):  
Test Data ◽  
Model Test ◽  
Testing Technique ◽  
Full Size ◽  
Cavitation Inception ◽  
Different Types

In this paper the four main requirements for a propeller are dealt with. These requirements concern efficiency, cavitation, propeller-excited forces and stopping abilities. In a propeller diagram the characteristic efficiency curves for different conditions are explained. A comparison of the optimum efficiencies for various types of propulsors is given, and the applications on a 130,000-dwt tanker are considered. Cavitation-inception curves both for a specific propeller and for systematic propeller series are discussed. Predicted torque and thrust fluctuations, based on model-test data, and the results of measurements on the full-size ship are compared. Finally a quasi-steady testing technique, developed to analyze different types of stopping maneuvers, is described.

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