Coupling Effect of Vortex-Induced Vibration of a Submarine Pipeline and Local Scour Under Steady Current

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Qi Zhang ◽  
Xiang-Lian Zhou ◽  
Xiao-He Xia ◽  
Wan-Ling Li ◽  
Shuo Zhang
Keyword(s):  
Moving Objects ◽  
Coupling Effect ◽  
Diameter Ratio ◽  
Local Scour ◽  
Submarine Pipeline ◽  
Steady Current ◽  
Pipeline Vibration ◽  
Gmo Model ◽  
Fully Coupled ◽  
Good Agreement

The dynamic interaction between pipeline vibration and local scour is investigated numerically. The sediment scour model is adopted to calculate the local scour below pipeline. The general moving objects (GMO) model fully coupled with the fluids is established to simulate the pipeline vibration. The present results are consistent with the previous experimental results and show good agreement. The scour depth and scour hole scale are closely related to the amplitude of pipeline vibration. The effects of initial gap-to-diameter ratio, reduced velocity, and pipeline diameter on the local scour and pipeline vibration are investigated.

A non-local implicit gradient-enhanced model for thermomechanical behavior of shape memory alloys

2018 ◽  
Vol 29 (9) ◽  
pp. 1818-1834 ◽  
Author(s):  
Hojjat Badnava ◽  
Mohammad Mashayekhi ◽  
Mahmoud Kadkhodaei ◽  
Ahmad Amiri-Rad
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Coupling Effect ◽  
Three Dimensional ◽  
Finite Element Software ◽  
Non Local ◽  
Niti Shape Memory Alloys ◽  
Temperature Responses ◽  
Fully Coupled ◽  
Good Agreement

A three-dimensional, implicit gradient-enhanced, fully coupled thermomechanical constitutive model is developed within the framework of thermodynamic principles for NiTi shape memory alloys. This work focuses on unstable behaviors of NiTi samples under different thermomechanical loading conditions. Temperature variation and its coupling effect on non-local behavior of a shape memory alloy during a loading–unloading cycle at different strain rates are considered. The proposed constitutive equations are implemented into the finite element software ABAQUS, and the numerical investigations indicate that the used procedure is an effective computational tool for simulation of several behaviors of NiTi samples including phase front nucleation and propagation, stress–strain–temperature responses, and transformation-induced stress relaxation. The obtained results are shown to be in a good agreement with available experimental and numerical findings in the literature. The effectiveness of the model in removing mesh sensitivity is evaluated by investigating the mesh-dependence issue for the low strain rate problems through numerical examples.

Local scour around two pipelines in tandem in steady current

2015 ◽  
Vol 98 ◽  
pp. 1-15 ◽  
Author(s):  
Ming Zhao ◽  
Shailesh Vaidya ◽  
Qin Zhang ◽  
Liang Cheng
Keyword(s):  
Local Scour ◽  
Steady Current

Axial Load on the Submarine Pipeline Suspended Law of Vortex Induced Vibration

2011 ◽  
Vol 94-96 ◽  
pp. 1511-1514
Author(s):  
Yi Fei Yan
Keyword(s):  
Natural Frequency ◽  
Axial Force ◽  
Scientific Basis ◽  
Oil Field ◽  
Span Length ◽  
Submarine Pipeline ◽  
Vortex Induced Vibration ◽  
Vibration Effect ◽  
Pipeline Vibration ◽  
The Impact

The study is about submarine pipeline. Considering the impact of different axial force, The reduced velocity is introduced as the pipeline vibration effect of vortex trail releasing. The vibration parameters of the span pipeline are analyzed and vibration control formula is built. The natural span length of the submarine pipeline is calculated according to the DNV-OS-F101 rule. The natural frequency of the span pipeline and the allowable span length are solved. The case study of submarine pipeline in Chengdao oil field is made and the variation law of natural frequency of span pipeline is got. The stream reduced velocity decreases as the axial force increase. The theory analysis of the vortex induced vibration can provide the scientific basis for the safety design of offshore submarine pipeline.

A Reinforcement Design Method Based on Analysis of Large Openings in Cylindrical Pressure Vessels

1996 ◽  
Vol 118 (4) ◽  
pp. 502-506 ◽  
Author(s):  
M. D. Xue ◽  
K. C. Hwang ◽  
W. Lu¨ ◽  
W. Chen
Keyword(s):  
Fourier Series ◽  
Present Method ◽  
Fourier Coefficients ◽  
Design Method ◽  
Large Diameter ◽  
Pressure Vessels ◽  
Diameter Ratio ◽  
Cylindrical Coordinates ◽  
Reinforcement Design ◽  
Good Agreement

The analytical solution is given for two orthogonally intersecting cylindrical shells with large diameter ratio d/D subjected to internal pressure. The modified Morley equation is used for the shell with cutout and the Love equation for the tube with nonplanar end. The continuity conditions of forces and displacements at the intersection are expressed in 3-D cylindrical coordinates (ρ, θ, z), and are expanded in Fourier series of θ. The Fourier coefficients are obtained by numerical quadrature. The present results are in good agreement with those obtained by tests and by FEM for ρ0 = d/D ≤ 0.8. The typical curves of SCF versus t/T and d/DT and reinforcement coefficients g, h versus D/T0 for each ρ0 are given on the present method.

Wave-soil-pipe coupling effect on submarine pipeline on-bottom stability

2001 ◽  
Vol 17 (1) ◽  
pp. 86-96 ◽  
Author(s):  
Gu Xiaoyun ◽  
Gao Fuping ◽  
Pu Qun
Keyword(s):  
Coupling Effect ◽  
Submarine Pipeline ◽  
Pipe Coupling ◽  
Soil Pipe

Numerical modeling of local scour and forces for submarine pipeline under surface waves

2016 ◽  
Vol 116 ◽  
pp. 275-288 ◽  
Author(s):  
Ming-ming Liu ◽  
Lin Lu ◽  
Bin Teng ◽  
Ming Zhao ◽  
Guo-qiang Tang
Keyword(s):  
Numerical Modeling ◽  
Surface Waves ◽  
Local Scour ◽  
Submarine Pipeline

Effect of Reynolds Number on Local Scour Around a Monopile in Steady Current

2019 ◽  
Author(s):  
Xiaofan Lou ◽  
Kaibing Zhang ◽  
Zhenhong Chen
Keyword(s):  
Reynolds Number ◽  
Time Scale ◽  
Time History ◽  
Local Scour ◽  
Circular Cylinders ◽  
Scour Depth ◽  
Clear Water ◽  
Number Range ◽  
Steady Current ◽  
Equilibrium Scour Depth

Abstract The effect of Reynolds number (Re) on the local scour around a monopile encountering steady current was investigated experimentally in a water flume. The experiment was performed using circular cylinders with different diameters under two different freestream velocities, covering both clear-water and live-bed scours and a Reynolds number range of approximately 9,000–60,000. The time-series of the scour depth was recorded during the whole scour process and the scour pit was scanned after the scour process reached equilibrium. Results are presented in terms of the equilibrium scour depth, the time-scale of the scour process and the three-dimensional scour profile at different Reynolds numbers. For both clear-water and live-bed scours, the time history of the scour process indicate that the time-scale becomes larger as Re increases. It is also found that the normalized equilibrium scour depth, as well as the normalized scour radius, decrease with the increasing Re. An empirical equation of the equilibrium scour depth is derived as a function of Reynolds number based on the experimental results so as to better account for Re effect in the scour design.

Modeling and Simulation of Dynamic Mass Capture by Robot Manipulators Considering Structural Flexiblity

1998 ◽  
Author(s):  
J. Kövecses ◽  
W. L. Cleghorn ◽  
R. G. Fenton
Keyword(s):  
Degrees Of Freedom ◽  
Moving Objects ◽  
Second Phase ◽  
Finite Motion ◽  
Dynamic Mass ◽  
Mass Capture ◽  
Alternative Approach ◽  
Impulsive Constraints ◽  
Simulation Results ◽  
Good Agreement

Abstract In this paper we investigate the dynamics of the process when a robot intercepts and captures a moving object. This operation is called dynamic mass capture. The effects of structural flexibility of the robot is taken into consideration. In terms of time the analysis is divided into three phases: before interception (finite motion), at the vicinity of interception and capture (impulsive motion), and after interception (finite motion). Special attention is paid to the modeling of the second phase when the robot intercepts and captures a target and it becomes part of the end effector, thus, the system’s degrees of freedom and topology suddenly change. To describe this event, an alternative approach is proposed. This is based on the use of a class of impulsive constraints, the so-called inert constraints. Jourdain’s principle is employed to derive the dynamic equations for both finite and impulsive motions. Based on the proposed approach, simulation results are presented for a flexible slewing link capturing a moving target. These results are compared with the observations of an experiment. Good agreement is found between the experimental and simulation results, which suggests that the analysis presented in this paper can be used with confidence in investigations of robots intercepting and capturing moving objects.

The unsteady pressure field of a ducted impeller

1979 ◽  
Vol 90 (2) ◽  
pp. 209-226 ◽  
Author(s):  
Dac Q. Dang ◽  
D. H. Norrie
Keyword(s):  
Pressure Field ◽  
Three Dimensional ◽  
Diameter Ratio ◽  
Governing Equations ◽  
General Constraint ◽  
Unsteady Pressure ◽  
Ducted Propeller ◽  
Harmonic Components ◽  
Phase Angles ◽  
Good Agreement

Analyses based on a three-dimensional vortex-filament model are presented for the unsteady pressure field generated by a ducted propeller. An oscillating part is identified in the kernels and absolute terms of the governing equations for the harmonic components, allowing two methods to be developed for the solution of the higher harmonics. The first method is exact and is applicable to ducted propellers with practical configurations (small chord-to-diameter ratio) while the second is approximate but more suitable for ducted systems with large chord-to-diameter ratios. The second method was applied to a configuration for which experimental data were available and good agreement was obtained for pressure harmonic amplitudes downstream of the propeller and for phase angles upstream of the propeller.Special consideration was given to the Kutta-Joukowski condition at the duct trailing edge and a general constraint developed for the doubly coupled governing integral equations.

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