Transient Simulations of the Fluid–Structure Interaction Response of a Partially Confined Pipe Under Axial Flows in Opposite Directions

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Konstantinos Kontzialis ◽  
Kyriakos Moditis ◽  
Michael P. Païdoussis
Keyword(s):  
Numerical Study ◽  
Critical Value ◽  
Flow Speed ◽  
Physical Parameters ◽  
Structure Interaction ◽  
Transient Simulations ◽  
Flow Induced Vibrations ◽  
The Stability ◽  
Insight Into ◽  
Good Agreement

This paper presents a numerical study of the dynamic response and stability of a partially confined cantilever pipe under simultaneous internal and external axial flows in opposite directions. The onset of flow-induced vibrations is predicted by the developed numerical model, and moreover, limit-cycle motion occurs as the flow speed becomes larger than a critical value. The numerical results are in good agreement with existing experimental results. The simulation gives control over many physical parameters and provides a better insight into the dynamics of the pipe. A parametric study regarding the stability of the system for varying confinement length is performed. The current results show that there is an increase in the susceptibility of the system to instability as the extent of confinement is increased.

On the Soil-Structure Interaction Numerical Study of Strengthening Design of Sluice within Mining Subsidence Areas

2010 ◽  
Vol 163-167 ◽  
pp. 3640-3644
Author(s):  
Hong Chang ◽  
Jun Wu Xia ◽  
Hong Fei Chang ◽  
Feng Jie Zhang
Keyword(s):  
High Pressure ◽  
Pile Foundation ◽  
Soil Structure ◽  
Numerical Study ◽  
Mining Subsidence ◽  
Soil Structure Interaction ◽  
Analysis Model ◽  
Structure Interaction ◽  
Jet Grouting ◽  
The Stability

Finite element models, established using ANSYS, given the soil - structure interaction phenomena produced at the interface between the reinforced concrete structure and the soil, have been used to perform a parametric study of the strengthening design of the foundation and the sluice chamber within mining subsidence area. High pressure jet grouting pile is adopted to reinforce the foundation, this analysis model is simplified by the transformation from the pile foundation to the solid foundation, which reflects the characteristic of pile foundation. The strengthening design of the sluice chamber is a renovation from open style to frame, to increase the integral property. It is indicated that, using high pressure jet grouting pile to reinforce the foundation can apparently improve the stability of sluice in mining area. Nevertheless, it can't improve the stability of sluice through reinforcing the sluice chamber.

Experimental Investigation of the Internal Tube Flow Effect on the Vibration Response of the Tubes in Shell and Tube Heat Exchanger

2020 ◽  
Author(s):  
Muhammad Nouman Ali ◽  
Shahab Khushnood ◽  
Luqman Ahmad Nizam ◽  
Shahid Bashir ◽  
Akmal Hafeez
Keyword(s):  
Tube Bundle ◽  
Internal Flow ◽  
Vibration Response ◽  
Tube Flow ◽  
Shell Side ◽  
Tube Heat Exchanger ◽  
Flow Induced Vibrations ◽  
Shell And Tube ◽  
The Stability ◽  
Insight Into

In shell and tube heat exchangers, tube bundles often fail due to the flow-induced vibrations. In the current study, vibration response of the tubes, placed in the first and third row of the tube bundle, has been examined having a normal triangular arrangement with pitch-to-diameter (P/D) ratio of 1.44. Each tube is tested for three different inside tube flow velocities of 0.85, 0.9 and 1 m/s and five shell side velocities ranging from 0.9 to 1.3 m/s with an increment of 0.1 m/s. This is the first experiment of its kind that offers insight into the tube vibration behavior made of glass material. The experimental analysis shows that tubes with internal flow vibrate with higher amplitudes than tubes without internal flow. Furthermore, the vibration amplitude of the tube tends to rise with increase in internal tube velocity even for the same shell side velocity. For the current range of shell and tube side velocity, with the internal flow from the tube, the hydrodynamic mass of the tube increases significantly with enhanced damping and contributes towards the stability of the tubes in crossflow, the stability threshold is delayed and higher shell side velocities are allowed to enhance the heat transfer rate.

Forces on Nets With Bending Stiffness: An Experimental Study on the Effects of Flow Speed and Angle of Attack

2012 ◽  
Author(s):  
L. C. Gansel ◽  
Ø. Jensen ◽  
E. Lien ◽  
P. C. Endresen
Keyword(s):  
Flow Direction ◽  
Angle Of Attack ◽  
Flow Speed ◽  
Bending Stiffness ◽  
Torque Sensor ◽  
Drag And Lift Coefficients ◽  
Flow Speeds ◽  
Drag And Lift ◽  
The Stability ◽  
Good Agreement

This study investigates the effects of changes in flow speed and angle of attack on drag and lift forces on nets with bending stiffness. Today most fish cage nets are made from nylon, but new cage materials are proposed in order to improve the stability of cages in currents and waves, to reduce biofouling, prevent escapes, and to secure fish from predator attacks. The use of some of these materials leads to nets with bending stiffness in at least one direction. However, not much is known about the performance of such nets in currents and waves. In this study three different nets with bending stiffness were tested together with nylon nets. Net panels were subjected to different flow speeds at different angles between flow direction and net plane, and the forces on the nets were measured with a multi-axis force/torque sensor system. Based on the experiments, drag and lift coefficients were determined for the different net materials and compared to existing theory [1,2]. The results are in reasonably good agreement with the existing theory for the nets with low solidity, however, for nets with higher solidity the results are significantly lower than the drag and lift coefficients provided by Aarsnes [1] and Løland [2].

scholarly journals On the stability for three-dimensional disturbances of viscous fluid flow between parallel walls

1933 ◽  
Vol 142 (847) ◽  
pp. 621-628 ◽  
Keyword(s):  
Reynolds Number ◽  
Three Dimensional ◽  
Finite Size ◽  
Critical Value ◽  
The Stability ◽  
The One ◽  
Von Mises ◽  
Shearing Motion ◽  
Determining Factor ◽  
Good Agreement

The turbulence problem is still unsolved, through a number of valuable papers have been published on it comparatively recently. But, since Hopf and von Mises proved that uniform shearing motion between two parallel planes was stable for infinitesimal disturbances but unstable for disturbances of a finite size has become more and more widely held. Von mises suggested that the reoughness of the walls might be the determining factor, but the experiments of Schiller have shown that the degree of roughness of the walls is of negligible influence on the critical value of Reynold's number. He concluded that the breakdown of laminar flow depended primarily on the size of the initial disturbance, in agreement eith Osborne Reynold's view. Important papers have been published by Noether and Tollmien, whose conclusions are in contradiction to one another. On the one hand, Noether, by a formal investigation of the asymptotic solutions of the equation governing the two-dimensional disturbances of flow between parallel walls, claims to have proved that all velocity profiles are stable for all values of Reynolds' number. On the other hand, Tollmien has determined a critical value of Reynolds' number for the flow past a flat plate placed edgeways to the stream. This value is in good agreement with the experimental results. There are, however, certain points in his analysis which are not clear and it would be useful to know if the method gave results in agreement with those derived more strictly.

A Numerical Study on Oil Leakage and Damaged Stability of Oil Carrier

2010 ◽  
Author(s):  
Liang-Yee Cheng ◽  
Diogo Vieira Gomes ◽  
Kazuo Nishimoto
Keyword(s):  
Numerical Study ◽  
Two Dimensional ◽  
Analysis Software ◽  
Scaled Model ◽  
Oil Leakage ◽  
Oil Water ◽  
Moving Particle ◽  
The Stability ◽  
Damaged Stability ◽  
Good Agreement

The objective of the present paper is to carry out a study on coupled transient process of the oil leakage and the damaged stability of a crude oil carrier. For this purpose, numerical simulations based on MPS (Moving particle Semi-Implicit) method are carried out considering a two dimensional small scaled model and the oil-water multiphase flow with free surface. The results are compared with that obtained by the stability analysis software SSTAB, which provides the final list angle in case of the damage, and show good agreement.

Numerical Study of Overdriven Detonation Phenomenon

2005 ◽  
Author(s):  
K. Mahmadi ◽  
M. Souli ◽  
N. Aquelet
Keyword(s):  
Numerical Study ◽  
Detonation Pressure ◽  
Explicit Finite Element ◽  
Structure Interaction ◽  
High Velocity Impacts ◽  
Detonation Process ◽  
Material Points ◽  
Overdriven Detonation ◽  
Detonation Phenomenon ◽  
Good Agreement

The overdriven detonation refers to detonation process in which the main detonation parameters, such as detonation pressure and propagating velocity, exceed the corresponding Chapman-Jouguet (C-J) values. This kind of detonation can be occurred when the flyer plate of high velocity impacts the explosive. So, in this work numerical simulation of overdriven detonation (following O.D.D.) phenomenon, which brings out higher detonation pressures than C-J pressure of an explosive is considered. The shock-structure interaction in this fast event is modeled by a penalty coupling, which permits to couple a Lagrangian mesh of the plate to material points of a multi-material Eulerian flow. This technique has been used successfully in many areas of applications, including automotive and industrial fields. By using an explicit finite element method, a good agreement between numerical and experimental results will valid penalty coupling capabilities to solve accurately O.D.D. phenomenon.

Forces on Nets With Bending Stiffness—An Experimental Study on the Effects of Flow Speed and Angle of Attack

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
L. C. Gansel ◽  
Ø. Jensen ◽  
E. Lien ◽  
P. C. Endresen
Keyword(s):  
Flow Direction ◽  
Angle Of Attack ◽  
Flow Speed ◽  
Bending Stiffness ◽  
Torque Sensor ◽  
Drag And Lift Coefficients ◽  
Flow Speeds ◽  
Drag And Lift ◽  
The Stability ◽  
Good Agreement

This study investigates the effects of changes in flow speed and angle of attack on drag and lift forces on nets with bending stiffness. Today most fish cage nets are made from nylon, but new cage materials are proposed in order to improve the stability of cages in currents and waves, to reduce biofouling, prevent escapes, and to secure fish from predator attacks. The use of some of these materials leads to nets with bending stiffness in at least one direction. However, not much is known about the performance of such nets in currents and waves. In this study, three different nets with bending stiffness were tested together with nylon nets. Net panels were subjected to different flow speeds at different angles between flow direction and net plane, and the forces on the nets were measured with a multi-axis force/torque sensor system. Based on the experiments, drag, and lift coefficients were determined for the different net materials and compared to existing theory with which they are in reasonably good agreement for the nets with low solidity. However, for nets with higher solidity the results are significantly lower than the drag and lift coefficients provided other authors. Also, the change of drag coefficient with changing flow speed and angle of attack was different for a monofilament and a multifilament net with similar solidity and aperture form and size. These differences may partly be due to differences in twine structures and net construction between the monofilament and multifilament net and between nets used by other authors and in the present study.

scholarly journals Oscillatory Kelvin–Helmholtz instability. Part 1. A viscous theory

2011 ◽  
Vol 675 ◽  
pp. 223-248 ◽  
Author(s):  
HARUNORI N. YOSHIKAWA ◽  
JOSÉ EDUARDO WESFREID
Keyword(s):  
Asymptotic Theory ◽  
Oscillation Amplitude ◽  
Critical Value ◽  
Linear Perturbation ◽  
Relative Importance ◽  
Helmholtz Instability ◽  
Dynamical Regimes ◽  
Validity Condition ◽  
The Stability ◽  
Good Agreement

The stability of oscillatory two-layer flows is investigated with a linear perturbation analysis. An asymptotic case is considered where the oscillation amplitude is small when compared to the perturbation wavelength. The focus of the analysis is on the influence of viscosity and its contrast at the interface. The flows are unstable when the relative velocity of the layers is larger than a critical value. Depending on the oscillation frequency, the flows are in different dynamical regimes, which are characterized by the relative importance of the capillary wavelength and the thicknesses of the Stokes boundary layers developed on the interface. A particular regime is found in which instability occurs at a substantially lower critical velocity. The mechanism behind the instability is studied by identifying the velocity- and shear-induced components in the disturbance growth rate. They interchange dominance depending on the frequency and the viscosity contrast. Results of the analysis are compared with the experiments in the literature. Good agreement is found with the experiments that have a small oscillation amplitude. The validity condition of the asymptotic theory is estimated.

Numerical and Qualitative Analysis of a Single Particle Behavior in a Shear Driven Flow in Equilateral Triangular Cavity

2013 ◽  
Vol 465-466 ◽  
pp. 557-561
Author(s):  
Muhammad Ammar Nik Mutasim ◽  
Nasir Ali ◽  
M.S. Idris ◽  
Ahmed N. Oumer
Keyword(s):  
Fluid Flow ◽  
Numerical Study ◽  
Flow Speed ◽  
Numerical Results ◽  
Driven Cavity ◽  
The Past ◽  
Particle Flows ◽  
Equivalent Time ◽  
Surrounding Fluid ◽  
Good Agreement

Intesive research works have been done on solid particle flows for the past decades. However, prediction of accurate relationship between the particle and the surrounding fluid is still challenging. This study focuses on the experimental and numerical study of behavior of a particle flow in a lid-driven cavity of equilateral triangular shape. Numerical analysis was done using Finite Difference Method (FDM) with stream function vorticity approach. The center location of the fluid flow was treated assumed to be the particle motion. To check the validaty of the numerical results, experiment was done. The particle and fluid used for the experiment were water and silk, respectively. The particle is considered to be slightly buoyant towards water. In the experiment the fluid flow was based on horizontal translating motion where the particle was initially at rest at the bottom wall of the cavity. The fluid flow speed is set to laminar flow with Reynolds Number, Re = 0 to 1000. It was found that the silk particle moved to the preferential path of the primary vortex at equivalent time of 13 seconds. Generally, the experimetal and numerical results for the streamlines were in good agreement.

Numerical study on ice fragmentation by impact based on non-ordinary state-based peridynamics

2019 ◽  
Vol 04 (01) ◽  
pp. 1850006 ◽  
Author(s):  
Ying Song ◽  
Haicheng Yu ◽  
Zhuang Kang
Keyword(s):  
Experimental Data ◽  
Numerical Study ◽  
Plastic Material ◽  
Impact Loads ◽  
Plasticity Model ◽  
Continuous Contact ◽  
Contact Algorithm ◽  
Structure Interaction ◽  
Discontinuous Problems ◽  
Good Agreement

Ice-structure interaction is currently one of the hot topics in engineering fields and has not been addressed. Traditional numerical methods derived from classical continuum mechanics have difficulties in solving such discontinuous problems of ice fragmentations. In the present paper, a non-ordinary state-based peridynamics formulation is presented to simulate the behavior of the ice under impact loads applied by a rigid ball. Ice is assumed as a viscoelastic-plastic material and simulated by the modified Drucker–Prager plasticity model. The failure criterion of ice is defined based on fracture toughness. A continuous contact algorithm is adopted to detect the contact between the rigid ball and ice particles. It is shown that numerical results are in good agreement with experimental data from open-literatures, and the non-ordinary state-based peridynamics model can capture the detail fragmentation features of ice under impact loads.

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