Computation of flow past a rotating cylinder with an energy-dissipation model of turbulence

AIAA Journal ◽  
1977 ◽  
Vol 15 (2) ◽  
pp. 271-274 ◽  
Author(s):  
B. I. Sharma
Keyword(s):  
Energy Dissipation ◽  
Rotating Cylinder ◽  
Flow Past ◽  
Dissipation Model

scholarly journals Flow-induced vibrations of a rotating cylinder in an arbitrary direction

2018 ◽  
Vol 860 ◽  
pp. 739-766 ◽  
Author(s):  
Rémi Bourguet
Keyword(s):  
Three Dimensional ◽  
Rotating Cylinder ◽  
The Body ◽  
Arbitrary Direction ◽  
Fast Rotation ◽  
Flow Past ◽  
Symmetrical Configuration ◽  
Wide Range ◽  
Flow Induced Vibrations ◽  
The Impact

The flow-induced vibrations of an elastically mounted circular cylinder, free to oscillate in an arbitrary direction and forced to rotate about its axis, are examined via two- and three-dimensional simulations, at a Reynolds number equal to 100, based on the body diameter and inflow velocity. The behaviour of the flow–structure system is investigated over the entire range of vibration directions, defined by the angle $\unicode[STIX]{x1D703}$ between the direction of the current and the direction of motion, a wide range of values of the reduced velocity $U^{\star }$ (inverse of the oscillator natural frequency) and three values of the rotation rate (ratio between the cylinder surface and inflow velocities), $\unicode[STIX]{x1D6FC}\in \{0,1,3\}$, in order to cover the reference non-rotating cylinder case, as well as typical slow and fast rotation cases. The oscillations of the non-rotating cylinder ($\unicode[STIX]{x1D6FC}=0$) develop under wake-body synchronization or lock-in, and their amplitude exhibits a bell-shaped evolution, typical of vortex-induced vibrations (VIV), as a function of $U^{\star }$. When $\unicode[STIX]{x1D703}$ is increased from $0^{\circ }$ to $90^{\circ }$ (or decreased from $180^{\circ }$ to $90^{\circ }$), the bell-shaped curve tends to monotonically increase in width and magnitude. For all angles, the flow past the non-rotating body is two-dimensional with formation of two counter-rotating spanwise vortices per cycle. The behaviour of the system remains globally the same for $\unicode[STIX]{x1D6FC}=1$. The principal effects of the slow rotation are a slight amplification of the VIV-like responses and widening of the vibration windows, as well as a limited asymmetry of the responses and forces about the symmetrical configuration $\unicode[STIX]{x1D703}=90^{\circ }$. The impact of the fast rotation ($\unicode[STIX]{x1D6FC}=3$) is more pronounced: VIV-like responses persist over a range of $\unicode[STIX]{x1D703}$ but, outside this range, the system is found to undergo a transition towards galloping-like oscillations characterised by amplitudes growing unboundedly with $U^{\star }$. A quasi-steady modelling of fluid forcing predicts the emergence of galloping-like responses as $\unicode[STIX]{x1D703}$ is varied, which suggests that they could be mainly driven by the mean flow. It, however, appears that flow unsteadiness and body motion remain synchronised in this vibration regime where a variety of multi-vortex wake patterns are uncovered. The interaction with flow dynamics results in deviations from the quasi-steady prediction. The successive steps in the evolution of the vibration amplitude versus $U^{\star }$, linked to wake pattern switch, are not captured by the quasi-steady approach. The flow past the rapidly-rotating, vibrating cylinder becomes three-dimensional over an interval of $\unicode[STIX]{x1D703}$ including the in-line oscillation configuration, with only a minor effect on the system behaviour.

High-Speed Rarefied Flow Past a Rotating Cylinder: The Inverse Magnus Effect

AIAA Journal ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 1670-1681 ◽  
Author(s):  
Benzi John ◽  
Xiao-Jun Gu ◽  
Robert W. Barber ◽  
David R. Emerson
Keyword(s):  
High Speed ◽  
Rotating Cylinder ◽  
Rarefied Flow ◽  
Flow Past ◽  
Magnus Effect

scholarly journals Energy Dissipation Characteristics and Parameter Identification of Symmetrically Coated Damping Structure of Pipelines under Different Temperature Environment

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1283
Author(s):  
Feng Jiang ◽  
Zheyu Ding ◽  
Yiwan Wu ◽  
Hongbai Bai ◽  
Yichuan Shao ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Hysteresis Loop ◽  
Least Square Method ◽  
Least Square ◽  
Test Results ◽  
Restoring Force ◽  
Dissipation Model ◽  
Effects Of Temperature ◽  
Dissipation Test ◽  
Metal Wires

In this paper, a symmetrically coated damping structure for entangled metallic wire materials (EMWM) of pipelines was designed to reduce the vibration of high temperature (300 °C) pipeline. A series of energy dissipation tests were carried out on the symmetrically coated damping structure at 20–300 °C. Based on the energy dissipation test results, the hysteresis loop was drawn. The effects of temperature, vibration amplitude, frequency, and density of EMWM on the energy dissipation characteristics of coated damping structures were investigated. A nonlinear energy dissipation model of the symmetrically coated damping structure with temperature parameters was established through the accurate decomposition of the hysteresis loop. The parameters of the nonlinear model were identified by the least square method. The energy dissipation test results show that the symmetrically coated damping structure for EMWM of pipelines had excellent and stable damping properties, and the established model could well describe the changing law of the restoring force and displacement of the symmetrically coated damping structure with amplitude, frequency, density, and ambient temperature. It is possible to reduce the vibration of pipelines in a wider temperature range by replacing different metal wires.

The Effects of Energy Dissipation of the Closure Bolted Joints Under Vibration Behavior

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Qiang Cheng ◽  
Wenxiang Xu ◽  
Zhifeng Liu ◽  
Congbin Yang ◽  
Ying Li
Keyword(s):  
Energy Dissipation ◽  
Vibration Frequency ◽  
Cyclic Load ◽  
Fractal Theory ◽  
Operator Method ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Modal Shape ◽  
Factors Affecting ◽  
Dissipation Model

Abstract Bolted joints are widely used in mechanical construction due to their ease of disassembly. When the bolting member is subjected to the alternating load, the pretightening force is gradually reduced, which may cause the interface contact performance to decrease, and the surface may be microslipped. Preload relaxation of threaded fasteners is the main factor that influences the joint failure under normal cyclic loading, but it is difficult to monitor the energy dissipation between the interface of the bolted joint. This paper presents an energy dissipation model for the bolted joint based on two-degree-of-freedom vibration differential mathematical model. The parameters of the model is calculated by using the fractal theory and differential operator method. The efficiency of the proposed model is verified by experiments. The results show that the experimental modal shape agrees well with the theoretical modal shape. According to the change of cyclic load and vibration frequency, the vibration response and the law of energy dissipation under different factors can be obtained. The results show that the vibration frequency and cyclic load are the main factors affecting the energy dissipation between interfaces. The energy dissipation of the contact surface of the bolted joints account for the main part of the energy dissipation of the bolted structure. The results provide a theoretical basis for reducing the looseness of the bolt connection and ensuring the reliability of the equipment.

Flow past a rotating cylinder translating at different gap heights along a wall

2015 ◽  
Vol 57 ◽  
pp. 314-330 ◽  
Author(s):  
A. Rao ◽  
M.C. Thompson ◽  
T. Leweke ◽  
K. Hourigan
Keyword(s):  
Rotating Cylinder ◽  
Flow Past
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