Flow-Induced Transverse Vibration of a Cantilevered Prism and Vibration-Generated Power Using Magnetostrictive Material

2013 ◽  
Author(s):  
Takahiro Kiwata ◽  
Makoto Yamaguchi ◽  
Takaaki Kono ◽  
Toshiyuki Ueno
Keyword(s):  
Transverse Vibration ◽  
Flexural Rigidity ◽  
Flow Direction ◽  
Response Amplitude ◽  
Rectangular Prism ◽  
Magnetostrictive Material ◽  
Side Ratio ◽  
Damping Parameter ◽  
Increment Rate ◽  
Vibration Tests

Free-vibration tests of a cantilevered rectangular prism with a side ratio of less than D/H = 0.5 (D, depth of the rectangular prism in the flow direction; H, height of a rectangular prism) that experiences low-speed galloping at a lower reduced velocity than the resonant reduced velocity were conducted in a water tunnel. We also carried out a power generation experiment using an iron-gallium alloy, which is a magnetostrictive material, to investigate the possibility of harvesting energy from a flow-induced transverse vibration. The effects of the side ratio of the rectangular prism and the configuration of a fin that was fitted on the back of a rectangular prism to increase the flexural rigidity on the response amplitude were investigated. The vibration of a rectangular prism with D/H = 0.1 occurred at a lower reduced velocity than that of the other rectangular prisms. This prism has the largest increment rate of the non-dimensional response amplitude ηrms for reduced velocity Vr, and the vibration has an uniform amplitude for each reduced velocity. The reduced velocity at the 20% non-dimensional response amplitude of a rectangular prism Vr0.2 decreases linearly with decreasing side ratio D/H. The response amplitude of the rectangular prism with D/H = 0.2 is only slightly dampened for all values of the reduced mass-damping parameter Cn. The values of Vr0.2 of the rectangular prism with a fin increased as the depth ratio of the fin increased. The response amplitude of the rectangular prism with/without a fin was found to be related to the second moment of area of the prism. The energy harvester using magnetostrictive material and a rectangular prism with D/H = 0.2 generates a maximum electric power of 8.8 mW.

Transverse Vibration Characteristics of an Inclined Cantilevered Rectangular Prism in flow direction

2018 ◽  
Vol 2018 (0) ◽  
pp. S0510103
Author(s):  
Ryohei NAGASE ◽  
Takahiro KIWATA ◽  
Takaaki KONO ◽  
Barata La Ode ◽  
Toshiyuki UENO ◽  
...  
Keyword(s):  
Transverse Vibration ◽  
Flow Direction ◽  
Vibration Characteristics ◽  
Rectangular Prism

Transverse Vibration Characteristics of a Rectangular Prism with Small Side Ratio and Flow Field around the Prism

2017 ◽  
Vol 2017 (0) ◽  
pp. S0520506
Author(s):  
Shunichi MIZUKAMI ◽  
Takahiro KIWATA ◽  
Takaaki KONO ◽  
Barata La Ode ◽  
Toshiyuki UENO
Keyword(s):  
Flow Field ◽  
Transverse Vibration ◽  
Vibration Characteristics ◽  
Rectangular Prism ◽  
Side Ratio ◽  
Small Side

Flow-Induced Transverse Vibration of a Cantilevered Prism for Energy Harvesting

2014 ◽  
Author(s):  
Takahiro Kiwata ◽  
Makoto Yamaguchi ◽  
Aguri Nakajima ◽  
Takaaki Kono ◽  
Toshiyuki Ueno
Keyword(s):  
Power Generation ◽  
Cross Sections ◽  
Bluff Body ◽  
Flow Direction ◽  
Small Scale ◽  
Hydroelectric Power ◽  
Flow Induced Vibration ◽  
Magnetostrictive Material ◽  
Side Ratio ◽  
Transverse Galloping

Various types of hydroelectric power generators have been developed, and small-scale hydroelectric power generation is expected to provide an independent, dispersed power supply for harnessing hydro-energy of small-sized rivers and agricultural waterways. In order to investigate the effects of the geometric shape of a bluff body’s cross section on the flow-induced transverse-galloping vibration, we performed free-vibration tests of a cantilevered prism with three kinds of cross sections, i.e., rectangular, D-section, and triangular prisms. The effects of the side ratio D/H (where D: depth of a bluff body in the flow direction, H: height of a bluff body normal to the flow direction) and the turbulence intensity of the free stream on the flow-induced vibration were also investigated. It was found that the vibrations of the thin rectangular, D-section, and triangular prisms occur at lower reduced velocity than that of the thick prisms. We also carried out a power-generation experiment using iron-gallium alloy that is a kind of magnetostrictive material to investigate a possibility of harvesting energy from the transverse-galloping vibration in a water flow. The energy harvester using magnetostrictive material and a rectangular prism with D/H = 0.2 generated a maximum electric power of 0.35 W at a reduced velocity of Vr = 4.4.

Damping Characteristics of Fluidic Pressure-fed Mechanism for Positioning Applications

2021 ◽  
Author(s):  
Heebum Chun ◽  
Jungsub Kim ◽  
Hyoyoung Kim ◽  
ChaBum Lee
Keyword(s):  
Tracking Error ◽  
Open Loop ◽  
Pressure Level ◽  
Fluidic Channel ◽  
Positioning Control ◽  
Damping Characteristics ◽  
Novel Approach ◽  
Damping Parameter ◽  
Vibration Tests ◽  
Metal Additive

Abstract This paper represents a novel approach capable of in-process damping parameter control for nanopositioning systems by implementing a fluidic pressure-fed mechanism (FPFM). The designed internal fluidic channels inside the nanopositioning stage fabricated by a metal additive manufacturing process can be filled with various fluids such as air, water, and oil and pneumatically or hydraulically pressurized. The damping was experimentally characterized with respect to fluids and corresponding pressure level (80 psi) through free-vibration tests, hammering test, and sine input sweeping test in open-loop and closed-loop positioning control conditions. As a result, the FPFM revealed the following characteristics: (1) damping may increase when the internal fluidic channels filled with fluids and pressure level at 80 psi, (2) the dynamic system showed the highest damping when the water exists in internal channels, (3) the existence of fluids and certain pressure in the fluidic channel does not have a significant influence on the motion quality and positioning control, but tracking error was reduced by FPFM. It is expected that the FPFM method will be utilized for vibration and noise control applications for high precision dynamic systems.

Research on the Vibration of Sheet Metal near the Zinc Pot Area in Continuous Hot-Dip Galvanizing Line

2011 ◽  
Vol 141 ◽  
pp. 471-477 ◽  
Author(s):  
Pei Min Xu ◽  
Biao Wang ◽  
Jin Jie Ye ◽  
Hai Juan Zhang ◽  
Zhi Lai Huang ◽  
...  
Keyword(s):  
Sheet Metal ◽  
Transverse Vibration ◽  
Cooling Tower ◽  
The Other ◽  
Control Parameters ◽  
Main Factors ◽  
Axially Moving ◽  
Vibration Tests ◽  
Air Knife ◽  
Excited Resonance

Large vibration of the sheet metal near the air knife is one of the main factors controlling the accuracy of thickness of the cladding zinc in continuous hot-dip galvanizing line. Lots of vibration tests are carried out on the strip and main equipments in the zinc pot area of a galvanizing line during downtime and operation in order to diagnose causes of the large vibration of the strip near the air knife. Theoretic foundation of adjustment of control parameters to suppress the strip vibration is established. Main mechanisms of large vibration of the strip are found by the theory of the transverse vibration of axially moving continua. The first one is the resonance of forced vibration induced by support movement aroused by passive rollers’ sloshing in the zinc pot, and the other is the parametrically excited resonance of the strip induced by tension fluctuation enlarged by local structural resonances of the cooling tower.

Reynolds Number Effect on Vortex-Induced Vibration on a Two-Dimensional Circular Cylinder With Low Mass-Damping Parameter

2011 ◽  
Author(s):  
Juan B. V. Wanderley ◽  
Luiz F. Soares ◽  
Marcelo Vitola ◽  
Sergio H. Sphaier ◽  
Carlos Levi
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Lift Coefficient ◽  
The Body ◽  
Response Amplitude ◽  
Curvilinear Coordinates ◽  
Number Range ◽  
Vortex Induced Vibration ◽  
Damping Parameter ◽  
Low Mass

The vortex induced vibration (VIV) on a circular cylinder with low mass-damping parameter and low Reynolds number is investigated numerically as basis for applications on dynamics of risers used in the offshore oil and gas industry and as a first step before tackling the harder high Reynolds number problem. The cylinder is supported by a spring and a damper and free to vibrate in the transverse direction. The numerical solution of the Reynolds average Navier-Stokes equations written in curvilinear coordinates is obtained using an upwind and Total Variation Diminishing conservative scheme and the k-ε turbulence model is used to simulate the turbulent flow in the wake of the body. Results were obtained for the phase angle, response amplitude, frequency, and lift coefficient for a variation of reduced velocity from 2 to 12 and three different proportional variations of Reynolds number, 2000–6000, 2000–12000, and 2000–24000. The numerical results indicate the strong effect of the Reynolds number range on the response amplitude, lift coefficient, and frequency of oscillation for a low mass-damping parameter.

Modulus of Elasticity of Schizolobium amazonicum Wood Evaluated by Transversal Vibration Technique

2014 ◽  
Vol 912-914 ◽  
pp. 247-250 ◽  
Author(s):  
Diego Henrique de Almeida ◽  
Raquel Schmitt Cavalheiro ◽  
Fabiane Salles Ferro ◽  
Tiago Hendrigo de Almeida ◽  
André Luis Christoforo ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Specific Gravity ◽  
Moisture Content ◽  
Transverse Vibration ◽  
Modulus Of Elasticity ◽  
Low Density ◽  
Average Value ◽  
Vibration Technique ◽  
Small Incidence ◽  
Vibration Tests

Schizolobium amazonicum is being much used in Brazil for several purposes because, besides being a native Brazilian wood specie, has important features such as low density and small incidence of natural defects. At this point, researches with the purpose of obtaining further knowledge of their properties are being conducted to better targeting their use. The aim of this research is to evaluate the modulus of elasticity of structural size pieces of Schizolobium amazonicum wood using the technique of transverse vibration. Tests were carried out using 30 pieces (standard moisture content 12%) with sizes of 3 cm x 15 cm x 2.5 m. The average value of elastic modulus determined for lumber of Schizolobium amazonicum was interesting to its low specific gravity.

Transverse Vibration of Two Axially Moving Beams Connected by an Elastic Foundation

2005 ◽  
Author(s):  
Mohamed Gaith ◽  
Sinan Mu¨ftu¨
Keyword(s):  
Elastic Foundation ◽  
Transverse Vibration ◽  
Natural Frequencies ◽  
Flexural Rigidity ◽  
Beam Theory ◽  
Mode Shapes ◽  
Winkler Elastic Foundation ◽  
Canonical State ◽  
Axially Moving Beams ◽  
Axially Moving

Transverse vibration of two axially moving beams connected by a Winkler elastic foundation is analyzed analytically. The system is a model of paper and paper-cloth (wire-screen) used in paper making. The two beams are tensioned, translating axially with a common constant velocity, simply supported at their ends, and of different materials and geometry. Due to the effect of translation, the dynamics of the system displays gyroscopic motion. The Euler-Bernoulli beam theory is used to model the deflections, and the governing equations are expressed in the canonical state form. The natural frequencies and associated mode shapes are obtained. It is found that the natural frequencies of the system are composed of two infinite sets describing in-phase and out-of-phase vibrations. In case the beams are identical, these modes become synchronous and asynchronous, respectively. Divergence instability occurs at the critical velocity; and, the frequency-velocity relationship is similar to that of a single traveling beam. The effects of the mass, flexural rigidity, and axial tension ratios of the two beams, as well as the effects of the elastic foundation stiffness are investigated.

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