Effects of Sway Motion and Flow-Induced Vibration on Vortex Structure Behind Flexible Rectangular Plate

2011 ◽  
Author(s):  
Masaki Yonekura ◽  
Kei Watanabe ◽  
Shunsuke Yamada ◽  
Hitoshi Ishikawa
Keyword(s):  
Rectangular Plate ◽  
Vortex Structure ◽  
Particle Image ◽  
Flow Induced Vibration ◽  
Structure Interaction ◽  
Piv Measurement ◽  
Image Velocimetry ◽  
Flexible Rectangular Plate ◽  
Interaction Problem ◽  
Sway Motion

Vortex structure behind a flexible rectangular plate with sway motion and flow-induced vibration was experimentally investigated by wind tunnel experiment by using Particle Image Velocimetry (PIV). The flexible rectangular plate, which was made of a polyurethane block, was cantilevered on a flat plate. On the opposite end, top free end showed a sway motion in the downstream direction. Increasing sway angle, the top free end involved the flow-induced in-line vibration which has a small amplitude. This is a typical example of fluid-structure interaction problem. However more experimental research for the effects of the sway motion and the flow-induced vibration on vortex structure behind the rectangular plate is required. In this paper, we focus attention on the phase-averaged vortex structure when the amplitude of vibration is the largest and smallest case. PIV measurement was conducted to clarify the phase-averaged and the instantaneous vortex structure behind the swaying plate. We discussed the effect of sway motion and flow-induced vibration on vortex structure.

Flow-Structure Interaction Problem of a Pitched Baseball Without Spin (Knuckleball)

2010 ◽  
Author(s):  
Hiroshi Higuchi ◽  
Toshiro Kiura
Keyword(s):  
Vector Fields ◽  
Particle Image ◽  
Three Dimensional ◽  
Boundary Layer Transition ◽  
Asymmetric Flow ◽  
Layer Transition ◽  
Structure Interaction ◽  
Image Velocimetry ◽  
Wake Patterns ◽  
Interaction Problem

The “knuckleball” effect is believed to be caused by asymmetric flow separation over the baseball, but little is known about its flow physics. The baseball is gripped with the knuckles in a certain position and is pitched in a way that introduces nearly no rotation, resulting in erratic flight paths which confuse batters. In the experiment described in this paper, the flow near the seams of the baseball is visualized thoroughly and the velocity vector fields near the surface and in the wake are obtained with Digital Particle Image Velocimetry. Depending on its position, the seam is found to trigger the boundary layer transition thus delaying the separation, or to cause separation itself. Three-dimensional wake patterns associated with specific ball orientations are identified and related to the force variations on the ball.

scholarly journals Particle Image Velocimetry (PIV) Measurement of Flow Establishment Time in a Bath Agitated by Plunging Jet

2001 ◽  
Vol 87 (9) ◽  
pp. 571-578 ◽  
Author(s):  
Tomoyuki SHIMIZU ◽  
Manabu IGUCHI ◽  
Norihisa TSUDA
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Piv Measurement ◽  
Image Velocimetry

A Method of Measuring Turbulent Flow Structures With Particle Image Velocimetry and Incorporating Into Boundary Conditions of Large Eddy Simulations

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Puxuan Li ◽  
Steve J. Eckels ◽  
Garrett W. Mann ◽  
Ning Zhang
Keyword(s):  
Particle Image Velocimetry ◽  
Large Eddy Simulation ◽  
Boundary Conditions ◽  
Particle Image ◽  
Advantages And Disadvantages ◽  
Eddy Simulation ◽  
Piv Measurement ◽  
Image Velocimetry ◽  
Large Eddy ◽  
Inlet Conditions

The setup of inlet conditions for a large eddy simulation (LES) is a complex and important problem. Normally, there are two methods to generate the inlet conditions for LES, i.e., synthesized turbulence methods and precursor simulation methods. This study presents a new method for determining inlet boundary conditions of LES using particle image velocimetry (PIV). LES shows sensitivity to inlet boundary conditions in the developing region, and this effect can even extend into the fully developed region of the flow. Two kinds of boundary conditions generated from PIV data, i.e., steady spatial distributed inlet (SSDI) and unsteady spatial distributed inlet (USDI), are studied. PIV provides valuable field measurement, but special care is needed to estimate turbulent kinetic energy and turbulent dissipation rate for SSDI. Correlation coefficients are used to analyze the autocorrelation of the PIV data. Different boundary conditions have different influences on LES, and their advantages and disadvantages for turbulence prediction and static pressure prediction are discussed in the paper. Two kinds of LES with different subgrid turbulence models are evaluated: namely dynamic Smagorinsky–Lilly model (Lilly model) and wall modeled large eddy simulation (WMLES model). The performances of these models for flow prediction in a square duct are presented. Furthermore, the LES results are compared with PIV measurement results and Reynolds-stress model (RSM) results at a downstream location for validation.

scholarly journals Data assimilation method to de-noise and de-filter particle image velocimetry data

2019 ◽  
Vol 877 ◽  
pp. 196-213 ◽  
Author(s):  
Jurriaan J. J. Gillissen ◽  
Roland Bouffanais ◽  
Dick K. P. Yue
Keyword(s):  
Particle Image Velocimetry ◽  
Data Assimilation ◽  
Particle Image ◽  
Particle Image Velocimetry Data ◽  
Reconstruction Error ◽  
Integration Time ◽  
Piv Measurement ◽  
Image Velocimetry ◽  
The Difference ◽  
Filter Particle

We present a variational data assimilation method in order to improve the accuracy of velocity fields $\tilde{\boldsymbol{v}}$, that are measured using particle image velocimetry (PIV). The method minimises the space–time integral of the difference between the reconstruction $\boldsymbol{u}$ and $\tilde{\boldsymbol{v}}$, under the constraint, that $\boldsymbol{u}$ satisfies conservation of mass and momentum. We apply the method to synthetic velocimetry data, in a two-dimensional turbulent flow, where realistic PIV noise is generated by computationally mimicking the PIV measurement process. The method performs optimally when the assimilation integration time is of the order of the flow correlation time. We interpret these results by comparing them to one-dimensional diffusion and advection problems, for which we derive analytical expressions for the reconstruction error.

scholarly journals Development of the optical electronic setup for carrying out measurements by multicolor Particle Image Velocimetry

2021 ◽  
Vol 2127 (1) ◽  
pp. 012018
Author(s):  
S S Usmanova ◽  
N M Skornyakova ◽  
Yu S Belov ◽  
M V Sapronov ◽  
A V Kuchmenko ◽  
...  
Keyword(s):  
Experimental Data ◽  
Particle Image Velocimetry ◽  
Computer Model ◽  
Vortex Structure ◽  
Test Object ◽  
3D Model ◽  
Particle Image ◽  
Velocity Fields ◽  
Laboratory Sample ◽  
Image Velocimetry

Abstract The paper is devoted to development of the optical electronic setup for carrying out measurements by multicolor particle image velocimetry. The main advantage of this method is the ability to visualize vector velocity fields in several planes simultaneously. As a result a 3D model of a setup was developed, a laboratory sample was assembled and series of testing experiments were performed. As a test object, vortex structure formed by a chemical stirrer in a cuvette with liquid has been considered. The experimental data were compared with the computer model developed in SolidWorks and FlowVision software.

Particle Image Velocimetry (PIV) Measurement and Numerical Modeling of Flow Over Gravel Dune

2013 ◽  
pp. 535-543
Author(s):  
Artemis Motamedi ◽  
Hossein Afzalimehr ◽  
Gabriele Harb ◽  
Majid Galoie
Keyword(s):  
Numerical Modeling ◽  
Particle Image Velocimetry ◽  
Particle Image ◽  
Piv Measurement ◽  
Image Velocimetry

Two tandem cylinders of different diameters in cross-flow: flow-induced vibration

2017 ◽  
Vol 829 ◽  
pp. 621-658 ◽  
Author(s):  
Bin Qin ◽  
Md. Mahbub Alam ◽  
Yu Zhou
Keyword(s):  
Particle Image ◽  
Cross Flow ◽  
Careful Examination ◽  
Laser Vibrometer ◽  
Flow Induced Vibration ◽  
Frequency Responses ◽  
Tandem Cylinders ◽  
Image Velocimetry ◽  
Different Diameters ◽  
Fixed Cylinder

This paper presents a systematic study of the cross-flow-induced vibration on a spring-supported circular cylinder of diameter $D$ placed in the wake of a fixed cylinder of smaller diameter $d$. The ratios $d/D$ and $L/d$ are varied from 0.2 to 1.0 and from 1.0 to 5.5, respectively, where $L$ is the distance between the centre of the upstream cylinder to the forward stagnation point of the downstream cylinder. Extensive measurements are conducted to capture the cylinder vibration and frequency responses, surface pressure, shedding frequencies and flow fields using laser vibrometer, hot-wire, pressure scanner and particle image velocimetry techniques. Six distinct flow regimes are identified. It has been found that a violent vibration may erupt for the spring-supported cylinder, and its dependence on $d/D$ and $L/d$ is documented. A careful examination and analysis of the flow structure, along with the simultaneously captured pressure distribution around and vibration of the downstream cylinder, cast light upon the mechanisms behind this vibration and its sustainability. The roles of added mass, flow-induced damping and physical aspects in the process of initiating the vibration are discussed in detail.

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