Download or read book A Study of Suppression and Control of Vortex induced Vibrations Using Shape Memory Alloy Springs in a Portable Device written by Jorge A. Garza Correa and published by . This book was released on 2008 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Study on Passive Methods of Vortex Induced Vibrations Suppression written by Richardo A. Galvao and published by . This book was released on 2008 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: A number of engineering systems, including those found in offshore operations, are often affected by vortex-induced vibrations (VIV). This phenomenon is caused by the interaction between a structure and shed vortices which can result in large amplitude vibrations of the structure that may lead to severe damage over time. Repairs to these systems are costly and time-consuming. Significant effort has been expended to develop a means of eliminating the need of repairs from vibrations. An investigation was undertaken to find a method of suppressing vortex-induced vibrations of a cylinder in a fluid flow. Passive methods of altering the flow behavior around the structure to mitigate the hydrodynamic forces that cause VIV were considered. Structural enhancements to a cylinder were attempted to accomplish this goal. The study also aimed to reduce drag below that encountered for a bare cylinder in comparable flow in addition to reducing flow induced vibrations. A number of approaches attempted succeeded in accomplishing this goal.

Download or read book A Performance Evaluation of Vortex induced Vibration Suppression Devices for Marine Applications written by Junghan Lee and published by . This book was released on 1987 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Suppression of Vortex induced Vibrations written by R. J. Curran and published by . This book was released on 2004 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vortex induced Vibration Characteristics and Suppression Device Performance on a Low Mass Ratio Flexible Cylinder written by Kee Quen Lee and published by . This book was released on 2014 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigating Phenomena in Vortex induced Vibration of a Cylinder Using Controlled Vibration written by Timothy Lester Morse and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, we use controlled vibration, where we oscillate a rigid cylinder with a prescribed motion, in a fluid flow, in order to provide insight into aspects of vortex-induced vibration. We make extensive measurements of the fluid forces on a cylinder that oscillates sinusoidally, transverse to a free stream, at both Re = 4,000 and Re = 12,000, and generate high resolution contour plots of various fluid forcing quantities in the plane of normalized amplitude and wavelength. With such resolution, we are able to discover discontinuities in the force and phase contours, which enable us to clearly identify boundaries separating different fluid forcing regimes. These boundaries appear remarkably similar to boundaries separating different vortex formation modes in the Williamson & Roshko (1988) map of regimes. Wake vorticity measurements (using DPIV) exhibit the 2S, 2P, and P+S modes, as well as a regime where the vortex formation is not synchronized with the cylinder oscillation. A further new discovery is the existence of a region where two vortex formation regimes overlap. Associated with this overlap region, we identify a distinct mode of vortex formation where two pairs of vortices are shed per cycle of oscillation (similar to the 2P mode) but the secondary vortex is much weaker, which we have termed '2POVERLAP ', or simply the '2PO ' mode. This '2PO ' mode is of particular importance, as it is responsible for generating the peak resonant response of the body. By examining the energy transfer from fluid to body motion we predict the response of an elastically mounted cylinder that agrees remarkably well with measured free vibration responses. We introduce the concept of an "energy portrait", which allows us to identify stable and unstable amplitude response solutions and thus to predict clearly the hysteretic and intermittent switching mode transitions, both of which correspond with such phenomena measured from free vibration. In addition to predicting steady state (sinusoidal) behavior, we develop a quasi-steady model which allows us to predict the dynamics of a freely oscillating cylinder having transient or unsteady behavior. Using this model, we find a regime of normalized flow velocity where steady state vortex-induced vibrations cannot occur, and the cylinder can only oscillate with unsteady motion. Further studies include the effect of Reynolds number on the critical mass for an oscillating body, below which a structure will vibrate up to infinite normalized velocity. Finally, we measure the effect of spanwise end conditions on a free vibration response.

Download or read book Tremor Suppression with Shape Memory Alloy Vibration Absorber written by Pushkar Deshpande and published by . This book was released on 2016 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vortex Induced Vibration Universal Phenomena in Diverse Systems written by and published by . This book was released on 2007 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The long-term goals of the research under this award have been to discover and understand generic phenomena in a whole class of vortex-induced vibration systems. We discover, using novel controlled damping, that the immense scatter in the classical Griffin plot (peak amplitude versus mass-damping) over 3 decades, can now be collapsed beautifully if one renormalises the axes, taking into account the effect of Reynolds number, which was previously not considered. We find, from controlled vibration of a cylinder, using extremely high-resolution variation of parameters, that, for the first time, accurate prediction of vortex-induced vibration is possible by searching for stable solutions with positive excitation. We discover that rising bodies do not vibrate unless their mass falls below a special value, which coincides with critical mass found in VIV studies of elastically mounted bodies. Similar response branches are found for a wide set of VlV systems, and in all studies we find the existence of a critical mass. Our work has formed the basis of a number of comprehensive papers in Journal of Fluid Mechanics and other journals, and has led to an invited review of VlV in Annual Review of Fluid Mechanics (2004). The P.1. has founded and chained a series of international conferences on Bluff Body Wakes and Vortex-Induced Vibrations (USA in 1998, France in 2000, Australia in 2002, Greece in 2005, Brazil in 2007).

Download or read book A Computer Model of a Shape Memory Spring in a Cam Mechanism written by Bryes Arden Hornish and published by . This book was released on 2005 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Cam mechanisms are often used in high speed applications where dynamics can dominate the motion of the device. The manufacturing of these mechanisms can be expensive in small quantities, but fortunately mathematical representation can be used to predict high speed behavior. Because usage is seen in a large number of applications, it is important for a designer to have an array of tools to achieve a desired response. Damping is one such tool, however, conventional damping techniques may be unsuitable for many cam mechanisms. Recently, researchers have investigated using the damping properties of shape memory alloys for mechanical vibration control. Experimentation has proved much usefulness in vibration isolation applications, therefore, it is reasonable to assume that shape memory materials may also benefit can mechanisms. In this thesis a mathematical model, capable of incorporating shape memory alloy components, was created to study the affect of these materials on the dynamic response of cam mechanisms. In particular three variations of mechanisms, using both conventional and shape memory components, were analyzed and the results discussed"--P. iii.

Download or read book A Study of the Hydroelastic Vibrations of Spring supported Cylinders in a Steady Fluid Stream Due to Vortex Shedding written by Robert J. Glass and published by . This book was released on 1970 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: The steady state amplitude and frequency response for the vortex-induced transverse vibrations of a circular cylinder mounted on linear springs in a steady fluid stream was considered. The tests were conducted in water and the range of variations were: aspect ratio 16.5 to 29.9; the ratio of cylinder density to fluid density 0.718 to 8.67; Reynolds number: 1727 to 4317. The nondimensional frequency response was found to be a strong function of the cylinder-to-fluid density ratio. The nondimensional frequency response was found to be a strong function of the cylinder-to-fluid density ratio. The nondimensional amplitude response was found to be a function of cylinder-to-fluid density ratio, Reynolds number, and the dimensionless ratio of the free stream velocity divided by the product of natural frequency and cylinder diameter. The maximum nondimensional amplitude response was analyzed for the form of dependency and empirical equations were developed. (Author).

Download or read book Variable Structure Control of Vortex induced Vibration written by Nagy M. Hussein and published by . This book was released on 1994 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vortex induced Vibrations of a Pivoted Circular Cylinder and Their Control Using a Tuned mass Damper written by Sina Kheirkhah and published by . This book was released on 2011 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vortex-induced vibrations of a pivoted circular cylinder and control of these vibrations were investigated experimentally.

Download or read book Preliminary Tests on a Novel Device to Reduce Vortex Induced Vibrations written by M. J. Every and published by . This book was released on 1980 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanical Vibration Control Using Smart Material written by Rajkumar Velu and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vortex induced Vibration Absense of Lock in and Fluid Force Deduction written by Mohammad Reza Gharib and published by . This book was released on 1999 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Investigation of Vortex induced Vibration of a Circular Cylinder written by Asif Khalak and published by . This book was released on 1996 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laboratory scale Investigation of the Ventilated Trousers Device Acting as a Suppressor of Vortex induced Vibrations written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: