Download or read book An Analytical Mechanics Framework for Flow Oscillator Modeling of Vortex Induced Bluff Body Oscillations written by Sohrob Mottaghi and published by . This book was released on 2020 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: This self-contained book provides an introduction to the flow-oscillator modeling of vortex-induced bluff-body oscillations. One of the great challenges in engineering science also happens to be one of engineering design - the modeling, analysis and design of vibrating structures driven by fluid motion. The literature on fluid-structure interaction is vast, and it can be said to comprise a large fraction of all papers published in the mechanical sciences. This book focuses on the vortex-induced oscillations of an immersed body, since, although the importance of the subject has long been known, it is only during the past fifty years that there have been concerted efforts to analytically model the general behavior of the coupling between vortex shedding and structural oscillations. At the same time, experimentalists have been gathering data on such interactions in order to help define the various regimes of behavior. This data is critical to our understanding and to those who develop analytical models, as can be seen in this book. The fundamental bases for the modeling developed in this book are the variational principles of analytical dynamics, in particular Hamilton's principle and Jourdain's principle, considered great intellectual achievements on par with Newton's laws of motion. Variational principles have been applied in numerous disciplines, including dynamics, optics and quantum mechanics. Here, we apply variational principles to the development of a framework for the modeling of flow-oscillator models of vortex-induced oscillations.
Download or read book An Analytical Mechanics Framework for Flow Oscillator Modeling of Vortex Induced Bluff Body Oscillations written by Sohrob Mottaghi and published by Springer. This book was released on 2019-08-08 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: This self-contained book provides an introduction to the flow-oscillator modeling of vortex-induced bluff-body oscillations. One of the great challenges in engineering science also happens to be one of engineering design – the modeling, analysis and design of vibrating structures driven by fluid motion. The literature on fluid–structure interaction is vast, and it can be said to comprise a large fraction of all papers published in the mechanical sciences. This book focuses on the vortex-induced oscillations of an immersed body, since, although the importance of the subject has long been known, it is only during the past fifty years that there have been concerted efforts to analytically model the general behavior of the coupling between vortex shedding and structural oscillations. At the same time, experimentalists have been gathering data on such interactions in order to help define the various regimes of behavior. This data is critical to our understanding and to those who develop analytical models, as can be seen in this book. The fundamental bases for the modeling developed in this book are the variational principles of analytical dynamics, in particular Hamilton’s principle and Jourdain’s principle, considered great intellectual achievements on par with Newton’s laws of motion. Variational principles have been applied in numerous disciplines, including dynamics, optics and quantum mechanics. Here, we apply variational principles to the development of a framework for the modeling of flow-oscillator models of vortex-induced oscillations.
Download or read book Mechanics of Flow Induced Vibration written by Rajeev Jaiman and published by Springer Nature. This book was released on 2023-06-10 with total page 1028 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses various passive and active techniques for controlling unsteady flow dynamics and associated coupled mechanics of fluid-structure interaction. Coupled multiphysics and multidomain simulations are emerging and challenging research areas, which have received significant attention during the past decade. One of the most common multiphysics and multidomain problems is fluid-structure interaction (FSI), i.e., the study of coupled physical systems involving fluid and a structure that have a mechanical influence on each other. Regardless of the application area, the investigation toward modeling of fluid-structure interaction and the underlying mechanisms in dealing with coupled fluid-structure instability with real-world applications remains a challenge to scientists and engineers. This book is designed for students and researchers who seek knowledge of computational modeling and control strategies for fluid-structure interaction. Specifically, this book provides a comprehensive review of the underlying unsteady physics and coupled mechanical aspects of the fluid-structure interaction of freely vibrating bluff bodies, the self-induced flapping of thin flexible structures, and aeroelasticity of shell structures. Understanding flow-induced loads and vibrations can lead to safer and cost-effective structures, especially for light and high-aspect ratio structures with increased flexibility and harsh environmental conditions. Using the body-fitted and moving mesh formulations, the physical insights associated with structure-to-fluid mass ratios, Reynolds number, nonlinear structural deformation, proximity interference, near-wall contacts, free-surface, and other interacting physical fields are covered in this book. In conjunction with the control techniques, data-driven model reduction approaches based on subspace projection and deep neural calculus are covered for low-dimensional modeling of unsteady fluid-structure interaction.
Download or read book Study of Reduced Order Models for Vortex induced Vibration and Comparison with CFD Results written by Christopher W. Olenek and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Vortex-induced vibration (VIV) is a dynamic phenomenon that can occur when there is fluid flow past a bluff body with flexibility. Over time, VIV can cause fatigue damage, so it may be desirable to suppress these vibrations. It is important to understand how the system behaves when trying to control vibrations; a reduced order model may be an effective way to study the system dynamics. Developing a data driven model from simulation and/or experimental results can be difficult, but there are existing phenomenological models that attempt to describe VIV, several of which will be explored in this thesis. These models consist of a structural equation representing a simple sprung bluff body coupled to a wake equation representing the effects of the surrounding fluid on the oscillator; the latter is generally a nonlinear oscillator exhibiting limit cycle behavior. The coupling, structural equation, and type of nonlinearity in the wake equation vary between different models, and the effects of these differences will be explored. The parameters of these equations must be identified, and then results from these models will be compared with the results obtained from a high fidelity CFD simulation to determine the relative quality of each reduced order model. The deficiencies of each model and the effects they produce will also be explored. Finally, the most important traits of each reduced order model will be identified, and, finally, the best reduced order model, with specific parameter values, will be presented.
Download or read book A Discrete Vortex Model for Bluff Bodies in Oscillatory Flow written by Peter John Naylor and published by . This book was released on 1983 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling of Vortex Induced Oscillations Based on Indicial Response Approach written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-05 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The indicial response approach, a modeling approach originally used for studying nonlinear problems in flight dynamics is applied to the study of vortex-induced oscillations phenomena. The indicial response of the velocity field is derived for the problem studied with emphasis on physical postulates involved. A full account of fluid dynamics effects is taken by considering the incompressible Navier-Stokes equations. The theory is applied to the particular case of flow past a cylinder in periodically forced motion to derive some salient features. The indicial response approach is shown to be equivalent to a currently popular approach based on the use of the amplitude equation. Jump and hysteresis phenomena that experiments indicate occur within the lock-in regime (where the velocity field oscillates at the forcing frequency) are captured by the approach. Truong, Khiem Van Unspecified Center NCC2-634...
Download or read book Piezoelectric Energy Harvesting written by Alper Erturk and published by John Wiley & Sons. This book was released on 2011-04-04 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transformation of vibrations into electric energy through the use of piezoelectric devices is an exciting and rapidly developing area of research with a widening range of applications constantly materialising. With Piezoelectric Energy Harvesting, world-leading researchers provide a timely and comprehensive coverage of the electromechanical modelling and applications of piezoelectric energy harvesters. They present principal modelling approaches, synthesizing fundamental material related to mechanical, aerospace, civil, electrical and materials engineering disciplines for vibration-based energy harvesting using piezoelectric transduction. Piezoelectric Energy Harvesting provides the first comprehensive treatment of distributed-parameter electromechanical modelling for piezoelectric energy harvesting with extensive case studies including experimental validations, and is the first book to address modelling of various forms of excitation in piezoelectric energy harvesting, ranging from airflow excitation to moving loads, thus ensuring its relevance to engineers in fields as disparate as aerospace engineering and civil engineering. Coverage includes: Analytical and approximate analytical distributed-parameter electromechanical models with illustrative theoretical case studies as well as extensive experimental validations Several problems of piezoelectric energy harvesting ranging from simple harmonic excitation to random vibrations Details of introducing and modelling piezoelectric coupling for various problems Modelling and exploiting nonlinear dynamics for performance enhancement, supported with experimental verifications Applications ranging from moving load excitation of slender bridges to airflow excitation of aeroelastic sections A review of standard nonlinear energy harvesting circuits with modelling aspects.
Download or read book Vortex Induced Vibrations written by Vijay Matheswaran and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vortex shedding and Vortex Induced Vibrations (VIV) of bluff bodies is a fundamental problem in fluid mechanics. The ubiquity of vortex shedding and VIV in several engineering fields has meant that a significant amount of research has centered on this subject. Recent studies have focused on the extraction of energy from steady flow using bodies undergoing VIV. In this dissertation, a new model for flow around a circular cylinder called the Hybrid Potential Flow (HPF) model is presented. The HPF model incorporates potential flow methods, experimental data and von Karman’s representation of the vortex wake to construct a complete solution for flow around a circular cylinder in the sub-critical Reynolds number regime $300 \leq Re \leq 1.5 x 10^5).$ Shedding frequencies and forces due to vortex shedding are calculated and compared to published results. The HPF model is extended to other bluff body geometries using conformal mapping. A composition of Karman-Trefftz transformations and Fornberg’s method is used to construct a conformal map between the physical domain and the circle plane. The combination of the HPF model and conformal mapping can thus be used to quickly calculate vortex shedding behavior for various bluff bodies. Validation of theoretical results is done through experimental methods. A flow visualization technique to view the time-averaged wake behind bluff bodies is developed and presented. Wind tunnel tests are done to validate predicted shedding frequencies for various bluff body geometries. A proof-of-concept prototype of a device that extracts energy from steady flow using VIV is developed. Emphasis is laid on the device being of low cost and complexity. Finally, principal conclusions of this dissertation and recommendations for future work are presented.
Download or read book Proceedings of the 5th International Symposium on Fluid Structure Interaction Aeroelasticity Flow Induced Vibration and Noise written by M. P. Paidoussis and published by . This book was released on 2002 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the 5th International Symposium on Fluid Structure Interactions Aeroelasticity Flow Induced Vibration and Noise written by M. P. Paidoussis and published by . This book was released on 2002 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Fluid Oscillator Model for Vortex induced Oscillation of Circular Cross sections in Uniform Flow written by Mahmud Khomami Javadi and published by . This book was released on 1989 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Petroleum Abstracts written by and published by . This book was released on 1992 with total page 1716 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1994 with total page 1036 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Critical Review of the Intrinsic Nature of Vortex Induced Vibrations written by Turgut Sarpkaya and published by . This book was released on 2003 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a concise and comprehensive review of the progress made during the past two decades on vortex induced vibration (VIV) of mostly circular cylindrical structures subjected to steady uniform flow. The critical elements of the evolution of the ideas, theoretical insights, experimental methods, and numerical models are traced systematically; the strengths and weaknesses of the current state of the understanding of the complex fluid/structure interaction are discussed in some detail. Finally, some suggestions are made for further research on VIV. The organization of the paper is given at the end of the next section.
Download or read book An Examination of Wake Oscillator Models for Vortex Induced Vibrations written by and published by . This book was released on 2001 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental results for vortex-induced vibrations of both pivoted and non-pivoted cylinders in a crossflow are presented in this report. Simplified models involving two ordinary differential equations are reviewed and shown to exhibit many of the features of the experimental results. Results of perturbation analysis of the simplified model are presented and used to explain some qualitative features, such as resonant frequency locking and hysteresis, in terms of bifurcations in the slow flow.
Download or read book Mathematical Model for Vortex induced Oscillation written by Francis Ngai-Ho Lee and published by . This book was released on 1974 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling Vortex induced Fluid structure Interaction Using an Extension of Jourdain s Principle written by Sohrob Mottaghi and published by . This book was released on 2015 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: A first-principles variational approach is proposed for reduced-order order modeling of fluid-structure interaction systems, specifically vortex-induced vibration. Fluid-structure interaction has to be taken into account in design and analysis of a large portion of engineering applications, yet a comprehensive theoretical development where analytical equations are derived from first principles is nonexistent. Not only does there exist much ambiguity concerning the general behavior of such systems, but the nature of the Lagrangian-Eulerian transformation is yet to be fully understood. Also, a general variational principle that is purely defined in a Eulerian description is nonexistent. Consequently, the use of variational methods for fluid-structure interaction problems has been relatively successful only for simple problems. Moreover, a review of the literature suggests that the Navier-Stokes (N-S) equations could not be obtained using a variational principle. This can be avoided by using Jourdain's principle (JP). Therefore, we have modified Jourdain's principle and obtained the first purely Eulerian variational formulation. Subsequently, by extending the JP for systems of changing mass, we have shown that the N-S equations can be obtained via a variational approach. Moreover, having shown that conservative terms of the N-S equations do not commute with the Eulerian variational operator, a correction term is obtained that must be added to the classical energy equation in integral form for Newtonian incompressible viscous fluids. Regarding vortex-induced vibration, an elastically supported, inverted pendulum that is immersed in a flow is considered as a study system. The pendulum is allowed to move transversely to the flow direction. This problem has generally been used as a test bed of vortex-induced vibration models, as it provides a simple geometry, yet possesses the nonlinearity of these phenomena. It is shown that the reduced-order modeling can be done without any ad hoc assumptions regarding the fluid forcing function. There exists no reduced-order model in the literature that does not make such assumptions. Based on the theoretical results as well as the reduced-order model, we conclude that the first principles development herein is a viable framework for the modeling of complex fluid-structure interaction problems such as vortex-induced oscillations.
