Instabilities and sensitivities in a flow over a rotationally flexible cylinder with a rigid splitter plate

2021 ◽  
Vol 928 ◽  
Author(s):  
R.L.G. Basso ◽  
Y. Hwang ◽  
G.R.S. Assi ◽  
S.J. Sherwin
Keyword(s):  
Symmetry Breaking ◽  
Recirculation Zone ◽  
Splitter Plate ◽  
Flexible Plate ◽  
Instability Mode ◽  
Flexible Cylinder ◽  
Sensitivity Problem ◽  
Consistent Treatment ◽  
Physical Features ◽  
And Control

This paper investigates the origin of flow-induced instabilities and their sensitivities in a flow over a rotationally flexible circular cylinder with a rigid splitter plate. A linear stability and sensitivity problem is formulated in the Eulerian frame by considering the geometric nonlinearity arising from the rotational motion of the cylinder which is not present in the stationary or purely translating stability methodology. This nonlinearity needs careful and consistent treatment in the linearised problem particularly when considering the Eulerian frame or reference adopted in this study that is not so widely considered. Two types of instabilities arising from the fluid–structure interaction are found. The first type of instabilities is the stationary symmetry breaking mode, which was well reported in previous studies. This instability exhibits a strong correlation with the length of the recirculation zone. A detailed analysis of the instability mode and its sensitivity reveals the importance of the flow near the tip region of the plate for the generation and control of this instability mode. The second type is an oscillatory torsional flapping mode, which has not been well reported. This instability typically emerges when the length of the splitter plate is sufficiently long. Unlike the symmetry breaking mode, it is not so closely correlated with the length of the recirculation zone. The sensitivity analysis however also reveals the crucial role played by the flow near the tip region in this instability. Finally, it is found that many physical features of this instability are reminiscent of those of the flapping (or flutter instability) observed in a flow over a flexible plate or a flag, suggesting that these instabilities share the same physical origin.

MODELING AND CONTROL OF HORIZONTAL FLEXIBLE PLATE USING PID-CS CONTROLLER

2019 ◽  
Vol 42 (4) ◽  
pp. 138-142
Author(s):  
Mohammed Jawad Mohammed ◽  
Majida Khalil Ahmed ◽  
Basma Abdullah Abbas
Keyword(s):  
Flexible Plate ◽  
Modeling And Control ◽  
And Control

Displacement Estimation and Control of Water Hydraulic Flexible Cylinder

2020 ◽  
Vol 2020.58 (0) ◽  
pp. 11c2
Author(s):  
Wataru KOBAYASHI ◽  
Syujiro DOHTA ◽  
Tetsuya AKAGI ◽  
Shinsaku FUJIMOTO ◽  
Yusuke MIYAMOTO
Keyword(s):  
Flexible Cylinder ◽  
Displacement Estimation ◽  
Water Hydraulic ◽  
Estimation And Control ◽  
And Control

Symmetry Breaking and Nonlinear Electric Transport in van der Waals Nanostructures

2021 ◽  
Vol 12 (1) ◽  
pp. 201-223
Author(s):  
Toshiya Ideue ◽  
Yoshihiro Iwasa
Keyword(s):  
Symmetry Breaking ◽  
Electrical Transport ◽  
Second Harmonic ◽  
Photovoltaic Effect ◽  
Van Der Waals ◽  
Physical Property ◽  
Electric Transport ◽  
Nonlinear Transport ◽  
Nano Structure ◽  
And Control

The recent development of artificially fabricated van der Waals nanostructures makes it possible to design and control the symmetry of solids and to find novel physical properties and related functionalities. A characteristic physical property reflecting such symmetry breaking is the nonlinear response, which is typically studied as the second harmonic generation of light, although studies have recently expanded to include various transport phenomena. An important aspect of nonlinear transport for modern condensed matter physics is that it is not only a unique functionality of noncentrosymmetric systems but also an emergent property reflecting underlying physics such as spin–orbit interaction, superconductivity, magnetism, and band geometry/topology. In this article, we review the nonlinear electrical transport in noncentrosymmetric van der Waals nanostructures obtained by exfoliation, nano-structure fabrication, or the application of an electric field, in particular, nonreciprocal transport resulting from inversion symmetry breaking and the bulk photovoltaic effect in nanomaterials without conventional p- n junctions.

scholarly journals Study of Vortex-Shedding-Induced Vibration of a Flexible Splitter Plate Behind a Cylinder

2012 ◽  
Author(s):  
Jinmo Lee ◽  
Donghyun You
Keyword(s):  
Vortex Shedding ◽  
Splitter Plate ◽  
Flexible Plate ◽  
Stress Distributions ◽  
Computational Structural Dynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Vortex Shedding Frequency ◽  
Shedding Frequency ◽  
Drag And Lift ◽  
Rear Stagnation Point

Integrated computational fluid dynamics (CFD) and computational structural dynamics (CSD) simulations of flow over a cylinder with a flexible splitter plate attached to the rear stagnation point, are performed. Flow over a cylinder produces vortex shedding, which causes unsteady pressure and shear stress distributions over a flexible splitter plate. As a result, the flexible splitter plate vibrates with distinct frequencies, which are different from the vortex-shedding frequency and natural frequencies of the plate. A systematic and detailed analysis of the effects of the flexible plate on fluid-structure dynamics and on the drag and lift of the cylinder, is presented.

scholarly journals An exact analysis of unsteady MHD free convection flow of some nanofluids with ramped wall velocity and ramped wall temperature accounting heat radiation and injection/consumption

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Talha Anwar ◽  
Poom Kumam ◽  
Wiboonsak Watthayu
Keyword(s):  
Wall Temperature ◽  
Heat Radiation ◽  
Convection Flow ◽  
Wall Velocity ◽  
Mass And Heat Transfer ◽  
Isothermal Wall ◽  
Close Form ◽  
Physical Features ◽  
Heat Injection ◽  
And Control

Abstract This article investigates the influence of ramped wall velocity and ramped wall temperature on time dependent, magnetohydrodynamic (MHD) natural convection flow of some nanofluids close to an infinitely long vertical plate nested in porous medium. Combination of water as base fluid and three types of nanoparticles named as copper, titanium dioxide and aluminum oxide is taken into account. Impacts of non linear thermal radiation flux and heat injection/consumption are also evaluated. The solutions of principal equations of mass and heat transfer are computed in close form by applying Laplace transform. The physical features of connected parameters are discussed and elucidated with the assistance of graphs. The expressions for Nusselt number and skin friction are also calculated and control of pertinent parameters on both phenomenons is presented in tables. A comparative study is performed for ramped wall and isothermal wall to evaluate the application extent of both boundary conditions.

scholarly journals Spontaneous Symmetry-Breaking in the Corrosion Transformation of Ancient Bronzes

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 656
Author(s):  
Yanpeng Yang ◽  
Xiaojuan Cao ◽  
Yang Li ◽  
Zhongchi Wang ◽  
Bingjie Li ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Crystal Lattice ◽  
Spontaneous Symmetry Breaking ◽  
Energy Dispersive Spectrometer ◽  
Optical Microscope ◽  
Corrosion Products ◽  
High Symmetry ◽  
Lattice Type ◽  
General Law ◽  
And Control

In general, during long-term museum conservation, ancient bronzes will generate new corrosion products also called the “secondary corrosion” on the surface of the unearthed “primary corrosion” products due to various environmental conditions. In this paper, the corrosion stages of several ancient Chinese bronzes are characterized by using optical microscope (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and Raman spectrometer (Raman). It is found that there exist phase transformation relationships in between the “primary corrosion” and the “secondary corrosion” stages (i.e., (1) the crystal lattice type tends to transform from a high symmetry system to a low symmetry system; (2) in case of the same crystal lattice type, the corrosions exhibit an inter-transformation or symbiosis). It is interesting to note that these transformation rules are very consistent with the well-known physical law of “spontaneous symmetry-breaking”, which won the 2008 Nobel Prize in Physics and also has been considered to be general law of nature, in addition to the principle of Gibbs free energy reduction. The significance of this discovery allows us to achieve the predictability and controllability of the bronze corrosion products (i.e., to predict the corrosive trends in advance and control the “second corrosion” by adjusting the conservation conditions. This research provides a novel conservation concept of ancient bronzes.

Numerical Simulation and Control of the Flow Over a Backward Facing Ramp

2014 ◽  
Author(s):  
Charles-Henri Bruneau ◽  
Meriem Jedouaa ◽  
Khodor Khadra ◽  
Iraj Mortazavi
Keyword(s):  
Numerical Simulation ◽  
Recirculation Zone ◽  
Flow Behavior ◽  
Synthetic Jets ◽  
Direct Numerical Simulations ◽  
The Body ◽  
Two Dimensional ◽  
Rear Window ◽  
Simulation And Control ◽  
And Control

A two-dimensional backward facing ramp is used to represent a car simplified rear window. Direct numerical simulations are performed to describe the flow behavior over the ramp. Constant blowing jets and synthetic jets are applied on the body to control the flow. The results presented in this work show a significant reduction of the recirculation zone.

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