Comprehensive insight into cuttings motion characteristics in deviated and horizontal wells considering various factors via CFD simulation

2021 ◽  
pp. 109490
Author(s):  
Like Ma ◽  
Jianqing Lai ◽  
Xinxin Zhang ◽  
Zhanghui Wu ◽  
Lubo Tang
Keyword(s):  
Cfd Simulation ◽  
Horizontal Wells ◽  
Motion Characteristics ◽  
Insight Into

Higher-order Taylor approximation of finite motions in mechanisms

Robotica ◽  
2018 ◽  
Vol 37 (7) ◽  
pp. 1190-1201 ◽  
Author(s):  
J. J. de Jong ◽  
A. Müller ◽  
J. L. Herder
Keyword(s):  
Screw Theory ◽  
Recursive Algorithm ◽  
Higher Order ◽  
Parallel Mechanisms ◽  
Lie Group Theory ◽  
Loop Closure ◽  
Matrix Operations ◽  
Motion Characteristics ◽  
Derivatives Of ◽  
Insight Into

SUMMARYHigher-order derivatives of kinematic mappings give insight into the motion characteristics of complex mechanisms. Screw theory and its associated Lie group theory have been used to find these derivatives of loop closure equations up to an arbitrary order. In this paper, this is extended to the higher-order derivatives of the solution to these loop closure equations to provide an approximation of the finite motion of serial and parallel mechanisms. This recursive algorithm, consisting solely of matrix operations, relies on a simplified representation of the higher-order derivatives of open chains. The method is applied to a serial, a multi-DOF parallel, and an overconstrained mechanism. In all cases, adequate approximation is obtained over a large portion of the workspace.

scholarly journals Heave and Pitch Motions of a Towed Ship in Waves Incorporated with an Asymmetrical Bridle Towline Model

2019 ◽  
Vol 2 (1) ◽  
pp. 34-40
Author(s):  
Ahmad Fitriadhy ◽  
Nurul Aqilah Mansor ◽  
Nur Adlina Aldin
Keyword(s):  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Wave Condition ◽  
Pitch Motion ◽  
Calm Water ◽  
Motion Characteristic ◽  
Motion Characteristics ◽  
Sufficient Reduction ◽  
Sway Motion ◽  
Motion Amplitude

Investigation of a ship towing system performance in waves incorporated with an asymmetrical towline configuration is necessarily to be studied to ensure a towing safety of navigation. To achieve the objective, this paper presents the ship towing motion performance in waves using Computational Fluid Dynamic (CFD) approach. Here, the heave and pitch motions of the towed ship so-called barge has been analysed, where several effects of the towing angle and towing speeds have been taken into account. In the calm water condition, the results revealed that the increase of tow angle was proportional with the sufficient reduction of the sway amplitude motion and inversely proportional to her yaw motion. The increase of the asymmetrical tow angle, however, has led to increase her sway motion amplitude in wave condition and conversely reduced the tow speed increased. In addition to the pitch motion characteristic, it subsequently increased by 12.1% as the tow angle raised from 25° to 35°; meanwhile the pitch motion of barge has by 10.2% as the tow speed increased from 0.655 m/s to 0.728 m/s. This CFD simulation is very useful as the preliminary prediction on the heave and pitch motion characteristics ensure a safety navigation of a towed ship in waves.

CFD Simulation Research on Flow Characteristics of Fluidized Beds

2014 ◽  
Vol 881-883 ◽  
pp. 1809-1813
Author(s):  
Li Ning Han ◽  
Lu Min Wang
Keyword(s):  
Particle Size ◽  
Pressure Drop ◽  
Fluidized Bed ◽  
Fluidized Beds ◽  
Particle Distribution ◽  
Cfd Simulation ◽  
Fluid Model ◽  
Flow Characteristics ◽  
Fluidization Velocity ◽  
Motion Characteristics

The Euler-Euler two-fluid model incorporating the kinetic theory of granular flow was applied to simulate the gas-solid flow in fluidized beds. The pressure drop, particle distribution and motion characteristics were studied in this paper. In order to investigate the effect of structure of the fluidized bed on flow characteristics, fluidized beds with different diameters and structures were applied. User defined functions (UDF) were applied to study the flow characteristics when the particle size and mass changed over time. The results showed that with the increase of particle size, higher minimum fluidization velocity was required, but lower pressure drop was obtained. For a certain fluidizing medium, the bed critical fluidization velocity depended only on the size and nature of the particles. The structure of a fluidized bed had an influence on the particle distribution and motion characteristics.

Direct CFD Simulation and Experimental Study on Coupled Motion Characteristics of Ship and Tank Sloshing in Waves

2021 ◽  
Author(s):  
Weigang Huang ◽  
Tao He ◽  
Jiawei Yu ◽  
Qing Wang ◽  
Xianzhou Wang
Keyword(s):  
Degrees Of Freedom ◽  
Cfd Simulation ◽  
Experimental Results ◽  
Body Motion ◽  
Ship Motions ◽  
Rans Equations ◽  
Coupling Motion ◽  
Motion Characteristics ◽  
Cfd Method ◽  
Tank Sloshing

Abstract It is of great significance to study the tank sloshing, especially the coupling motion between tank sloshing and ship in waves with strong non-linearity and randomness. In this study, the response of the ship with/without tank in regular wave is studied by EFD method and CFD method. All the simulations are carried out by in-house CFD code HUST-Ship (hydrodynamic unsteady simulation technology of ship) to solve RANS equations coupled with six degrees of freedom solid body motion equations. RANS equations are solved by finite difference method and PISO algorithm. A two-equation Shear Stress Transport (SST) k-w turbulence model is used. The simulation results are in good agreement with the experimental results, which also indicates that the result of the tank sloshing simulated by in-house CFD code is reliable. The influence of sloshing on ship motions is estimated by comparing the experimental results between the ship with/without tank in different wave conditions. The coupling motion characteristics between the liquid in the tank and the ship is further studied by the CFD method. The study shows that the influence of tank sloshing on ship motion is different under the action of different regular waves.

scholarly journals CFD ANALYSIS ON VERTICAL MOTION OF A FULL-SCALE FLOATING JETTY

2020 ◽  
Vol 15 (6) ◽  
pp. 100-110
Author(s):  
AHMAD FITRIADHY ◽  
◽  
AMIRA ADAM
Keyword(s):  
Cfd Simulation ◽  
Vertical Motion ◽  
Cfd Analysis ◽  
Subsequent Increase ◽  
Pitch Motion ◽  
Motion Responses ◽  
Harsh Environmental Condition ◽  
Computational Fluid Dynamics Cfd ◽  
Response Amplitude Operators ◽  
Motion Characteristics

A floating jetty often experiences several vertical motions i.e., heave and pitch motion responses due to harsh environmental condition. This inherently makes discomfort to everyone during berthing on a floating; and even it potentially leads to loss of life due to falling down into the sea. A preliminary analysis using Computational Fluid Dynamics (CFD) simulation is necessary to be conducted to ensure user’s safety. The CFD analysis focused on the interaction between wave motions and the floating jetty and its effects on the vertical motions. The vertical motions of floating jetty were quantified by the Response Amplitude Operators (RAO). Several effects due to variation of wavelength (λ/L) have been studied. The CFD results revealed that the lower wavelength (λ/L<2.25) resulted in the increase of the heave and pitch motion amplitudes proportionally. However, the subsequent increase of wavelength (2.25>λ/L) has given results to less heave and pitch motion amplitudes. In general, it is shown that the vertical motion characteristics of the floating jetty predominantly depend on wave properties.

CFD Performance Analysis of a Flowmaker

2006 ◽  
Author(s):  
Lasse A. Rosendahl ◽  
Xiaopeng Wang ◽  
Christian B. Jacobsen
Keyword(s):  
Cfd Simulation ◽  
Laser Doppler Anemometry ◽  
Near Field ◽  
Proximity Effects ◽  
Scale Model ◽  
Valuable Insight ◽  
Mean Flow ◽  
Multiple Frame ◽  
Wall Proximity ◽  
Insight Into

In the present work, the mean flow field in a stirred tank equipped with a scale model of a commercially available Grundfos AFG.40.230.35 flowmaker is investigated using CFD simulation and Laser Doppler Anemometry (LDA), in order to provide information on the interaction between flow, propeller and wall proximity. The propeller is placed at a specified location in the tank, and measurements are taken at various locations in the tank to provide as detailed a representation of the resulting flow as possible as well as insight into the near-field of the flowmaker. The simulation, carried out with Ansys CFX 10, used a multiple frame of reference (MFR) approach to include a full representation of the flowmaker blade and motor geometry, to fully include the effects of the blade shape and variable pitch. The reported results are based on a k-e model using a second order discretization scheme. The results show good agreement on downstream axial velocities immediately after the flowmaker, although the numerical results exhibit symmetry to a greater extent than the experimental data, which is believed to be due to a combination of wall proximity effects in the latter and the turbulence model in the latter. However, the results provide valuable insight into the performance of CFD analysis on this type of flow maker, and highlight aspects for future work.

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