H-Shaped Pontoon Deepwater Floating Production Semisubmersible

2007 ◽  
Author(s):  
Alaa M. Mansour ◽  
Edward W. Huang
Keyword(s):  
Vertical Motion ◽  
Numerical Results ◽  
Angular Motion ◽  
The Other ◽  
Hydrodynamic Performance ◽  
Horizontal Motion ◽  
Strength Design ◽  
Global Performance

This paper presents a new deepwater floating production semisubmersible concept, namely H-Pontoon Semi. The H-pontoon semi consists of an H-shaped pontoon structure which has a pair of parallel longer main pontoons and a pair of shorter secondary central pontoons disposed inwardly from the outer ends of the main pontoons and supported by the two main pontoons. The H-pontoon includes four columns placed at or inboard of the edge of main pontoons. The H-shaped pontoon structure improves the hydrodynamic performance of the platform as compared to conventional ring pontoon structures. The asymmetric pontoon spacing in the horizontal plan provides a reduced horizontal and angular motion in one direction over the other. Additionally, the inward position of the secondary central pontoons facilitates the support of SCR and allows a reduced vertical motion at the SCR fairlead locations. This reduced vertical and horizontal motion at the SCR fairlead help the SCR fatigue and strength design and consequently reduce the SCR associated cost. Numerical results for the global performance of the H-Pontoon platform are presented to illustrate the advantages of the newly developed H-Pontoon Semi concept over the conventional semisubmersible.

Induced Motion as a Function of the Speed of the Inducing Object, Measured by Means of Two Methods

Perception ◽  
1979 ◽  
Vol 8 (3) ◽  
pp. 255-262 ◽  
Author(s):  
Walter C Gogel
Keyword(s):  
Apparent Motion ◽  
Vertical Motion ◽  
The Other ◽  
Horizontal Motion ◽  
Horizontal Distance ◽  
Vector Addition ◽  
Stationary Disc ◽  
Induced Motion ◽  
Frame Motion

Induced motion is illustrated by the apparent motion imparted to a stationary disc by the horizontal motion of an enclosing frame. The present study examined the effect of frame speed, with a constant extent of frame motion, on the magnitude of induced motion for average frame speeds varying from 0·17 to 2·85 deg s−1. The induced motion was measured by two methods. (i) The observer adjusted the horizontal distance between comparison posts to indicate the extent of the horizontal induced motion in a physically stationary disc. (ii) The observer adjusted the slant of a comparison rod to indicate the apparent path of motion of the disc physically moving straight up and down in phase with the horizontal motion of the surrounding frame. The latter method requires the observer to integrate two apparent components of motion of the disc, one from its physical vertical motion and the other from its induced horizontal motion. The results from both methods show that substantial amounts of induction occurred at all of the frame speeds. The vector addition of apparent motions from real and from induced motion obtained from the second method, and the substantial amounts of induction found with the high frame speeds are interpreted to indicate that the processes underlying the perception of real and induced motion are essentially the same.

Granitoid complexes and the Archean tectonic record in the southern part of northwestern Ontario

1979 ◽  
Vol 16 (10) ◽  
pp. 1965-1977 ◽  
Author(s):  
W. M. Schwerdtner ◽  
D. Stone ◽  
K. Osadetz ◽  
J. Morgan ◽  
G. M. Stott
Keyword(s):  
Large Scale ◽  
Vertical Motion ◽  
Strike Slip ◽  
Horizontal Motion ◽  
Tectonic Deformation ◽  
Northwestern Ontario ◽  
Greenstone Belts ◽  
Second Period ◽  
Transcurrent Faults ◽  
Regional Compression

Two principal, possibly overlapping, periods of tectonic deformation can be distinguished in the Archean of northwestern Ontario, a period of dominantly vertical-motion tectonics and a period of dominantly horizontal-motion tectonics. Gigantic diapirs of foliated to gneissic tonalite–granodiorite developed during the first period and appear to be responsible for the gross structure of, and the major folds within, the metavolcanic–metasedimentary masses ("greenstone belts"). These diapirs are most likely due to mechanical remobilization of early tabular batholiths which originally intruded the oldest supracrustal rocks presently exposed. Later massive to foliated, dioritic to granitic plutons that vary from concordant, crescentic plutons to partly discordant plutons of various shapes and sizes were emplaced into the diapirs.The second period of tectonic deformation is characterized by large-scale dextral shearing and the development of major transcurrent faults under northwesterly regional compression. The strike-slip motions of this period outlasted the late plutonism, and led to the development of mylonitic zones which cut all Archean granitoid plutons.

Observations Regarding Numerical Results Obtained by the Floquet-Method

2013 ◽  
Author(s):  
Till J. Kniffka ◽  
Horst Ecker
Keyword(s):  
Numerical Methods ◽  
Monodromy Matrix ◽  
Mathieu Equation ◽  
Numerical Results ◽  
The Other ◽  
Benchmark Problem ◽  
Stability Studies ◽  
Floquet Method ◽  
System Equations ◽  
Time Periodic

Stability studies of parametrically excited systems are frequently carried out by numerical methods. Especially for LTP-systems, several such methods are known and in practical use. This study investigates and compares two methods that are both based on Floquet’s theorem. As an introductary benchmark problem a 1-dof system is employed, which is basically a mechanical representation of the damped Mathieu-equation. The second problem to be studied in this contribution is a time-periodic 2-dof vibrational system. The system equations are transformed into a modal representation to facilitate the application and interpretation of the results obtained by different methods. Both numerical methods are similar in the sense that a monodromy matrix for the LTP-system is calculated numerically. However, one method uses the period of the parametric excitation as the interval for establishing that matrix. The other method is based on the period of the solution, which is not known exactly. Numerical results are computed by both methods and compared in order to work out how they can be applied efficiently.

Motion Characteristics of Composite-Type Sea Cage under Pure Wave

2012 ◽  
Vol 490-495 ◽  
pp. 3405-3409
Author(s):  
Chun Liu Li ◽  
Yun Peng Zhao
Keyword(s):  
Experimental Data ◽  
Wave Height ◽  
Vertical Motion ◽  
Data Acquisition System ◽  
Horizontal Motion ◽  
Wave Condition ◽  
Composite Type ◽  
Motion Range ◽  
Motion Characteristics ◽  
Sea Cage

To study motion range changes with wave condition and motion relationship between cages, physical model experiments were carried out. The authors designed 2 models of composite-type sea cages. Experimental data obtained by the CCD data acquisition system. The experiment results showed that 1.in the same period, horizontal motion range,vertical motion range and inclination changes of float collar increase with wave height; 2.In the same wave height, horizontal motion range of the float collar increases with period; 3.The laws between vertical motion and period are not obvious 4.The laws between inclination changes and period are not obvious 5.Motion range of the first cage along the direction of waves is less than other cages.

Impact of Innovative Capital on the Global Performance of the European Union

2021 ◽  
pp. 90-124
Author(s):  
Cristina Raluca Gh. Popescu
Keyword(s):  
The Other ◽  
Free Access ◽  
The European Union ◽  
Dynamic Component ◽  
Successful Model ◽  
Global Performance ◽  
Potential Factors ◽  
And Performance ◽  
The One ◽  
Access Data

With the main objective of determining the essential factors that incorporate or enhance innovative capital, the present study, based, on the one hand, on the evaluation of the literature, allowed identifying ten potential factors and centered, on the other hand, on the analysis represented by the linear regression facilitated displaying the interdependencies between these factors and performance, thus determining the overall meaning and intensity of their contribution. In order to identify general and essential trends, to eliminate the cyclical influences of innovative capital, the present study was conducted on the basis of public and free access data contained by Eurostat, the transparency and accessibility of information being very important criteria in defining a simple and successful model, applicable for assessing the contribution of intellectual capital, in general, and its most dynamic component of innovative capital to increasing the performance of organizations.

scholarly journals Computational study on the aerodynamics of a long-shrouded contra-rotating rotor in hover

2019 ◽  
Vol 11 ◽  
pp. 175682931983368
Author(s):  
Chao Huo ◽  
Peng Lv ◽  
Anbang Sun
Keyword(s):  
Flow Field ◽  
Opposite Direction ◽  
Computational Study ◽  
Flow Characteristics ◽  
The Other ◽  
Complex Flow ◽  
Sliding Mesh ◽  
Global Performance ◽  
Mesh Method ◽  
Downstream Flow

This paper aims to investigate the aerodynamics including the global performance and flow characteristics of a long-shrouded contra-rotating rotor by developing a full 3D RANS computation. Through validations by current experiments on the same shrouded contra-rotating rotor, the computation using sliding mesh method and the computational zone with an extended nozzle downstream flow field effectively works; the time-averaged solution of the unsteady computation reveals that more uniform flow presents after the downstream rotor, which implies that the rear rotor rotating at opposite direction greatly compensates and reduces the wake; the unsteady computations further explore the flow field throughout the whole system, along the span and around blade tips. Complex flow patterns including the vortices and their interactions are indicated around the blade roots and tips. For further identifying rotor configurations, the rotor–rotor distance and switching two rotor speeds were studied. The computation reveals that setting the second rotor backwards decreases the wake scale but increases its intensity in the downstream nozzle zone. However, for the effect of switching speeds, computations cannot precisely solve the flow when the rear rotor under the windmill because of the upstream rotor rotating much faster than the other one. All the phenomena from computations well implement the experimental observations.

scholarly journals Numerical Analysis on the Effect of Artificial Ventilated Pipe Diameter on Hydrodynamic Performance of a Surface-Piercing Propeller

2019 ◽  
Vol 7 (8) ◽  
pp. 240
Author(s):  
Gao ◽  
Yang ◽  
Li ◽  
Dong
Keyword(s):  
High Speed ◽  
Water Immersion ◽  
Active Role ◽  
Numerical Results ◽  
Hydrodynamic Performance ◽  
Pipe Diameter ◽  
Pressure Area ◽  
Cfd Method ◽  
Thrust And Torque ◽  
Surface Piercing Propeller

Under the condition of large water immersion, surface-piercing propellers are inclined to be heavy loaded. In order to improve the hydrodynamic performance of the surface-piercing propeller, the installation of a vent pipe in front of a propeller disc is more widely used in the propulsion device of high speed planning crafts. Based on computational fluid dynamics (CFD) method, this paper studied the influence of diverse vent pipe diameters on hydrodynamic performance of the surface-piercing propeller under full water immersion conditions. The numerical results show that, with the increase of vent pipe diameters, the thrust and torque of the surface-piercing propeller decrease after ventilation, and the efficiency of the propeller increases rapidly; the low pressure area near the back root of the blade becomes smaller and smaller gradually; and the peak of periodic vibration of thrust and torque can be effectively reduced. The numerical results demonstrate that the installation of artificial vent pipe effectively improves the hydrodynamic performance of surface piercing propeller in the field of high speed crafts, and the increase of artificial vent pipe diameter plays an active role in the propulsion efficiency of the surface-piercing propeller.

scholarly journals Quadrotor Formation Strategies Based on Distributed Consensus and Model Predictive Controls

2018 ◽  
Vol 8 (11) ◽  
pp. 2246 ◽  
Author(s):  
Chia-Wei Chang ◽  
Jaw-Kuen Shiau
Keyword(s):  
Formation Control ◽  
Vertical Motion ◽  
Formation Flight ◽  
Horizontal Motion ◽  
Motion Simulation ◽  
Linear Quadratic ◽  
Distributed Consensus ◽  
Consensus Control ◽  
Formation Pattern ◽  
The Given

In this study, the distributed consensus control and model predictive control (MPC)-based formation strategies for quadrotors are proposed. First, the formation-control problem is decoupled into horizontal and vertical motions. The distributed consensus control and MPC-based formation strategy are implemented in the follower’s horizontal formation control. In the horizontal motion, the leader tracks the given waypoints by simply using the MPC, and generates the desired formation trajectory for each follower based on its flight information, predicted trajectory, and the given formation pattern. On the other hand, the followers carry out the formation flight based on the proposed horizontal formation strategy and the desired formation trajectories generated by the leader. In the vertical motion, formation control is carried out using only the MPC for both the leader and the follower. Likewise, the leader tracks the desired altitude/climb rate and generates the desired formation trajectories for the followers, and the followers track the desired formation trajectories generated by the leader using the MPC. The optimization problem considered in the MPC differs for the horizontal and vertical motions. The problem is formulated as a quadratic programming (QP) problem for the horizontal motion, and as a linear quadratic tracker (LQT) for the vertical motion. Simulation of a comprehensive maneuver was carried out under a Matlab/Simulink environment to examine the performance of the proposed formation strategies.

Re-entry guidance method based on decoupling control variables and waypoint

2019 ◽  
Vol 123 (1262) ◽  
pp. 523-535 ◽  
Author(s):  
Z. Li ◽  
T. Yang ◽  
Z. Feng
Keyword(s):  
Vertical Motion ◽  
Decoupling Control ◽  
Horizontal Motion ◽  
Motion Model ◽  
Control Variables ◽  
The Earth ◽  
Entry Guidance ◽  
Trajectory Guidance ◽  
Loss Of Motion ◽  
Control Accuracy

ABSTRACTGenerally, earth rotating and non-spherical perturbation of the earth in re-entry motion model are simplified using the standard trajectory guidance method. The re-entry motion is also simplified to horizontal motion and vertical motion and controlled, respectively. The simplification of re-entry motion model will lead to loss of motion accuracy and location accuracy. The direct decomposition will lead to the reduction of control accuracy because the horizontal motion and the vertical motion are coupled in re-entry. To improve the standard trajectory guidance method, the standard trajectory guidance method based on decoupling control variables and waypoint is proposed in this paper. The proposed guidance method will not simplify earth rotating and non-spherical perturbation of the earth in motion equation or decompose the re-entry motion to horizontal motion and vertical motion. Trajectory waypoint is adopted to reduce the change frequency of tracking states, because tracking states change frequently if the entire standard trajectory is tracked in real time.

Numerical Simulation on the Electrophoretic Motion of Multiple Particles in Microchannels

2004 ◽  
Author(s):  
Chunzhen Ye ◽  
Dongqing Li
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Electric Field ◽  
Particle Motion ◽  
Outer Region ◽  
Numerical Results ◽  
The Other ◽  
Double Layers ◽  
Rectangular Microchannel ◽  
Moving Particle

This paper considers the electrophoretic motion of multiple spheres in an aqueous electrolyte solution in a straight rectangular microchannel, where the size of the channel is close to that of the particles. This is a complicated 3-D transient process where the electric field, the flow field and the particle motion are coupled together. The objective is to numerically investigate how one particle influences the electric field and the flow field surrounding the other particle and the particle moving velocity. It is also aimed to investigate and demonstrate that the effects of particle size and electrokinetic properties on particle moving velocity. Under the assumption of thin electrical double layers, the electroosmotic flow velocity is used to describe the flow in the inner region. The model governing the electric field and the flow field in the outer region and the particle motion is developed. A direct numerical simulation method using the finite element method is adopted to solve the model. The numerical results show that the presence of one particle influences the electric field and the flow field adjacent to the other particle and the particle motion, and that this influences weaken when the separation distance becomes bigger. The particle motion is dependent on its size, with the smaller particle moving a little faster. In addition, the zeta potential of particle has an effective influence on the particle motion. For a faster particle moving from behind a slower one, numerical results show that the faster moving particle will climb and then pass the slower moving particle then two particles’ centers are not located on a line parallel to the electric field.

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