scholarly journals Numerical Analysis of Hydrodynamic Characteristics for Various Types of Jack-up Legs

2014 ◽  
Vol 28 (5) ◽  
pp. 371-377 ◽  
Author(s):  
Ji-Seok Kim ◽  
Min-Su Park ◽  
Weoncheol Koo
2013 ◽  
Vol 339 ◽  
pp. 628-631
Author(s):  
Jian Zhang ◽  
Wen Xian Tang ◽  
Wen Long Qin ◽  
Chao Gao

Quasi-static numerical model of jack-up spudcan penetration in layered sandy soil was presented in this paper, based on explicit procedure. Three different methods, such as Lagrangian analysis, Lagrangian analysis with distortion control and Lagrangian-Eulerian analysis, were used to control soil negative element volumes or other excessive distortion. The results showed that, reasonable and stable numerical results could be solved by Lagrangian-Eulerian analysis. The magnitude of plastic strain, however, decreases at first and then increases to the maximum.


2015 ◽  
Vol 775 ◽  
pp. 247-251
Author(s):  
Sang Hwan Heo ◽  
Weon Cheol Koo ◽  
Min Su Park ◽  
Sung Jae Kim

In this study, the hydrodynamic characteristics of an X-braced-type jack-up leg with pile-soil foundation were investigated. Using the modified Morison equation and substructure method, wave excitation forces with effects of soil-structure interaction were calculated. The natural period and mode vector of the structure were obtained by using modal analysis. Newmark-beta time-integration method was used to predict the dynamic responses of the structure in the time domain. The maximum displacement and bending stress of the structure were analyzed under various soil conditions.


2020 ◽  
Author(s):  
Bendaoud Nadia ◽  
Mehala Kadda

Hydrodynamic bearing are components that provide the guiding in rotation of rotating machines, such as turbines, the reactors. This equipment works under very severe operating conditions: high rotational speed and high radial load. In order to improve the hydrodynamic performance of these rotating machines, the industrialists specialized in the manufacture of hydrodynamic journal bearings, have designed a bearing model with its textured interior surface. The present work is a numerical analysis, carried out to observe the effect of a turbulent fluid flow in a non-textured and textured plain bearing and to thus to see the improvement of the hydrodynamic and tribological performances to a non- textured and textured surface of the plain bearing, under severe operating parameters. The rotational velocity varies from 11,000 to 21,000 rpm and radial load ranging from 2000 N to 9000 N. The numerical analysis is performed by solving the continuity equation of Navier-Stocks, using the finite volume method. The numerical results show that the most important hydrodynamic characteristics such as pressure, flow velocity of the fluid, friction torque, are significant for the textured plain bearing under rotational velocity of 21,000 rpm and radial load 10,000 N compared to obtained for a non-textured plain bearing.


2003 ◽  
Vol 19 (2-3) ◽  
pp. 152-159 ◽  
Author(s):  
X. M. Tang ◽  
J. Li ◽  
C. Lu ◽  
Q. H. Cheng
Keyword(s):  

Author(s):  
Bendaoud Nadia ◽  
Mehala Kadda

Hydrodynamic plain bearings are components that provide the guiding in rotation of rotating machines, such as turbines, the reactors. This equipment works under very severe operating conditions. In order to improve the hydrodynamic performance of these rotating machines, the industrialists specialized in the manufacture of hydrodynamic bearings have designed a bearing model with its textured interior surface. The numerical analysis is carried out to study the for both plain bearings types with a textured a non-textured surface thus to see the improvement of the plain bearing hydrodynamic performances, as well as the fluid flow behavior in motion. The analysis is performed by solving the continuity equation of Navier-Stokes, by the finite volume method, using CFD code. The numerical results show that the most important hydrodynamic characteristics such as pressure, minimal film thickness, friction torque, leakage flow, are significant for the textured plain bearing under rotational velocity of 6000rpm and radial load 10000N compared to obtained for a non-textured plain bearing.


Author(s):  
Zhaode Zhang ◽  
Yuhong Wang

The motion response of a mat-support jack-up during positioning is studied in this paper using numerical analysis software SESAM. In the process of jack-up positioning, the square bottom mat is gradually lowered and the floating jack-up, secured by anchor chains, moves in six degrees of freedom in response to the dynamic loading of wave, current and wind combined. Numerical simulations are carried out to solve motion responses of the floating structure with mat at different depths. The sensitivity of motion responses to wave periods and directions are analyzed. The maximum motion amplitudes under the design environmental conditions and the risk of the mat crashing with the seafloor are evaluated.


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