Evaluation of Side Boundary Effects on Dynamic Numerical Modeling for Centrifugal Model Tests

2008 ◽  
Vol 12 (5) ◽  
pp. 760-778
Author(s):  
Chih-Wei Lu ◽  
Shing-Cheng Lai
Author(s):  
Donghwan Lee ◽  
Zhenjia (Jerry) Huang

Abstract For floating production platform such as FPSO and FLNG, it is important to use confidently estimated roll damping coefficients in the prediction of its motions in waves since in many cases the roll response is mainly contributed from resonance. Traditionally roll damping prediction was made through model tests or empirical formulas. As computing power and numerical modeling techniques have been improved during last a few decades, offshore industry starts to consider CFD as an alternative engineering and design tool complementary and/or supplementary to physical model tests. This paper presents our verification and validation work of modeling practices with commercially available CFD software for engineering applications for FPSO roll decay damping in calm water. The numerical modeling followed a recommended modeling practice developed by a Joint Development Project – TESK JDP [1].


2011 ◽  
Vol 368-373 ◽  
pp. 959-962
Author(s):  
Yong Zhi Wang ◽  
Xiao Ming Yuan ◽  
Rui Sun

By special advantages and progress of dynamic centrifugal model tests, construction and development of large scale centrifugal shakers are driven. As one subsystem of a large scale centrifugal shaker, the testing auxiliary system is used to data acquisition, image acquisition and model making. The perfect design and construction of a testing auxiliary system must give a guarantee for dynamic centrifugal model tests. This paper outlines the components and function of the testing auxiliary system of a large scale centrifugal shaker. The basic design requirements and critical techniques relevant to data acquisition systems, image acquisition systems and containers are analyzed according to the characteristics of dynamic centrifugal model tests on a large scale centrifugal shaker, meanwhile, some specific conception and design suggestions are proposed. The results can offer some references for design of the testing auxiliary system of a large scale centrifugal shaker.


2011 ◽  
Vol 2011 (0) ◽  
pp. _J192015-1-_J192015-5
Author(s):  
Daisuke INOUE ◽  
Yoshitaka YANAGIHARA ◽  
Hiroshi UENO ◽  
Shinichiro NISHIDA

2006 ◽  
Vol 59 (1) ◽  
pp. 33-49 ◽  
Author(s):  
Xin Zhang ◽  
Willem Toet ◽  
Jonathan Zerihan

We review the progress made during the last 30years on ground effect aerodynamics associated with race cars, in particular open wheel race cars. Ground effect aerodynamics of race cars is concerned with generating downforce, principally via low pressure on the surfaces nearest to the ground. The “ground effect” parts of an open wheeled car’s aerodynamics are the most aerodynamically efficient and contribute less drag than that associated with, for example, an upper rear wing. While drag reduction is an important part of the research, downforce generation plays a greater role in lap time reduction. Aerodynamics plays a vital role in determining speed and acceleration (including longitudinal acceleration but principally cornering acceleration), and thus performance. Attention is paid to wings and diffusers in ground effect and wheel aerodynamics. For the wings and diffusers in ground effect, major physical features are identified and force regimes classified, including the phenomena of downforce enhancement, maximum downforce, and downforce reduction. In particular the role played by force enhancement edge vortices is demonstrated. Apart from model tests, advances and problems in numerical modeling of ground effect aerodynamics are also reviewed and discussed. This review article cites 89 references.


2014 ◽  
Vol 1049-1050 ◽  
pp. 242-245
Author(s):  
Jun Ling Qiu ◽  
Jin Xing Lai

Centrifugal modeling technology has been applied to geotechnical engineering for more than half a century. It has been an important and indispensible means to simulate the geotechnical behavior because it has the same material, the similar boundary conditions and the same stress level. And it is also commonly used in tunnel-related research. Centrifugal tests of pipe-roof and small pipe grouting in tunnel were analyzed, the important effects of centrifugal tests on preliminary support of the tunnel were also emphasized. Problems often met in model tests of tunnelling were solved, such as structure model, modeling soil, preliminary support model and general programming of experiment proposal. The future development of centrifuges in tunnelling is also presented.


1978 ◽  
Vol 15 (1) ◽  
pp. 14-31 ◽  
Author(s):  
A. N. Schofield

Centrifugal model tests increase total stress levels in small models made of natural or reconstituted soil, and allow direct observation of repeated failures. A novel use of a basket centrifuge is described in which slopes can be tested without end effects. When a series of models at various overconsolidation ratios was tested to failure the error in the safety factor predicted by a total stress analysis increased with the overconsolidation ratio. Other centrifuges are discussed and the advantage of large machines with balanced arms and swinging carriages are explained. Soil material behaviour discussed includes heat transfer and leaching. The paper concludes with a review of the present availability of and prospects for centrifugal model tests.


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