Advanced Methods for Dynamic Aeroelastic Analysis of Rotors PDF Download
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Author: Nicolas Reveles
Publisher:
ISBN:
Category : Aeroelasticity
Languages : en
Pages :
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Book Description
Simulations play an integral role in the understanding and development of rotor- craft aeromechanics. Computational Fluid Dynamics coupled with Computational Structural Dynamics (CFD/CSD) offers an excellent approach to analyzing rotors. These methods have been traditionally "loosely-coupled" where data are exchanged periodically, motion is prescribed for CFD, and the updated loads have a static component for CSD. Loosely-coupled CFD/CSD assumes the solution to be periodic, which may not be true for some simulations. "Tightly-coupled" CFD/CSD, where loads and motion are exchanged at each time step, does not make this periodic assumption and opens up new avenues of simulation to research. A major drawback to tightly-coupled CFD/CSD is an increase in computational cost. Different approaches are explored to reduce this cost as well as examine numerical implications in solutions from tightly and loosely-coupled CFD/CSD. A trim methodology optimized for tightly-coupled simulations is developed and found to bring trim costs within parity of loosely-coupled CFD/CSD simulations. Aerodynamic loading is found to be nearly similar for fixed controls. However, the lead-lag blade motion is determined to contain a harmonic in the tightly-coupled analysis that is not an integer multiple of the rotor speed. A hybrid CFD/CSD methodology employing the use of a free-wake code to model the far-field effects of the rotor wake is developed to aid in computational cost reduction. Investigation of this approach reveals that computational costs may be reduced while preserving solution accuracy. This work's contributions to the community include the development of a trim algorithm appropriate for use in tightly-coupled CFD/CSD simulations along with a detailed examination of the physics predicted by loose and tight coupling for quasi-steady level flight conditions. The influence of the wake in such cases is directly examined using a modular hybrid coupling to a free-wake code that is capable of reduced cost computations.
Author: Nicolas Reveles
Publisher:
ISBN:
Category : Aeroelasticity
Languages : en
Pages :
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Book Description
Simulations play an integral role in the understanding and development of rotor- craft aeromechanics. Computational Fluid Dynamics coupled with Computational Structural Dynamics (CFD/CSD) offers an excellent approach to analyzing rotors. These methods have been traditionally "loosely-coupled" where data are exchanged periodically, motion is prescribed for CFD, and the updated loads have a static component for CSD. Loosely-coupled CFD/CSD assumes the solution to be periodic, which may not be true for some simulations. "Tightly-coupled" CFD/CSD, where loads and motion are exchanged at each time step, does not make this periodic assumption and opens up new avenues of simulation to research. A major drawback to tightly-coupled CFD/CSD is an increase in computational cost. Different approaches are explored to reduce this cost as well as examine numerical implications in solutions from tightly and loosely-coupled CFD/CSD. A trim methodology optimized for tightly-coupled simulations is developed and found to bring trim costs within parity of loosely-coupled CFD/CSD simulations. Aerodynamic loading is found to be nearly similar for fixed controls. However, the lead-lag blade motion is determined to contain a harmonic in the tightly-coupled analysis that is not an integer multiple of the rotor speed. A hybrid CFD/CSD methodology employing the use of a free-wake code to model the far-field effects of the rotor wake is developed to aid in computational cost reduction. Investigation of this approach reveals that computational costs may be reduced while preserving solution accuracy. This work's contributions to the community include the development of a trim algorithm appropriate for use in tightly-coupled CFD/CSD simulations along with a detailed examination of the physics predicted by loose and tight coupling for quasi-steady level flight conditions. The influence of the wake in such cases is directly examined using a modular hybrid coupling to a free-wake code that is capable of reduced cost computations.
Author: Arne Vollan
Publisher: CRC Press
ISBN: 1439847703
Category : Science
Languages : en
Pages : 299
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Book Description
For more than a century, we have had a firm grasp on rotor dynamics involving rigid bodies with regular shapes, such as cylinders and shafts. However, to achieve an equally solid understanding of the rotational behavior of flexible bodies—especially those with irregular shapes, such as propeller and turbine blades—we require more modern tools and methods. Computational Techniques of Rotor Dynamics with the Finite Element Method explores the application of practical finite element method (FEM)-based computational techniques and state-of-the-art engineering software. These are used to simulate behavior of rotational structures that enable the function of various types of machinery—from generators and wind turbines to airplane engines and propellers. The book’s first section focuses on the theoretical foundation of rotor dynamics, and the second concentrates on the engineering analysis of rotating structures. The authors explain techniques used in the modeling and computation of the forces involved in the rotational phenomenon. They then demonstrate how to interpret and apply the results to improve fidelity and performance. Coverage includes: Use of FEM to achieve the most accurate computational simulation of all gyroscopic forces occurring in rotational structures Details of highly efficient and accurate computational and numerical techniques for dynamic simulations Interpretation of computational results, which is instrumental to developing stable rotating machinery Practical application examples of rotational structures’ dynamic response to external and internal excitations An FEM case study that illustrates the computational complexities associated with modeling and computation of forces of rotor dynamics Assessment of propellers and turbines that are critical to the transportation and energy industries Useful to practicing engineers and graduate-level students alike, this self-contained volume also serves as an invaluable reference for researchers and instructors in this field. CRC Press Authors Speak Louis Komzsik introduces you to two books that share a common mathematical foundation, the finite element analysis technique. Watch the video.
Author: Andrew D. Dimarogonas
Publisher: Springer Science & Business Media
ISBN: 9400759053
Category : Technology & Engineering
Languages : en
Pages : 280
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Book Description
The design and construction of rotating machinery operating at supercritical speeds was, in the 1920s, an event of revolutionary importance for the then new branch of dynamics known as rotor dynamics. In the 1960s, another revolution occurred: In less than a decade, imposed by operational and economic needs, an increase in the power of turbomachinery by one order of magnitude took place. Dynamic analysis of complex rotor forms became a necessity, while the importance of approximate methods for dynamic analysis was stressed. Finally, the emergence of fracture mechanics, as a new branch of applied mechanics, provided analytical tools to investigate crack influence on the dynamic behavior of rotors. The scope of this book is based on all these developments. No topics related to the well-known classical problems are included, rather the book deals exclusively with modern high-power turbomachinery.
Author: Richard L. Bielawa
Publisher: Amer Inst of Aeronautics &
ISBN: 9781563470318
Category : Aeroelasticity.
Languages : en
Pages : 562
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Book Description
Drawing on his extensive experience as a practicing engineer, designer, educator, and researcher in rotorcraft, the author presents a comprehensive account of the fundamental concepts of structural dynamics and aeroelasticity for conventional rotary wing aircraft, as well as for the newly emerging tilt-rotor and tilt-wing concepts. Intended for use in graduate-level courses and by practicing engineers, the volume covers all of the important topics needed for the complete understanding of rotorcraft structural dynamics and aeroelasticity, including basic analysis tools, rotating beams, gyroscopic phenomena, drive system dynamics, fuselage vibrations, methods for controlling vibrations, dynamic test procedures, stability analysis, mechanical and aeromechanical instabilities of rotors and rotor-pylon assemblies, unsteady aerodynamics and flutter of rotors, and model testing. The text is further enhanced by the inclusion of problems in each chapter.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 46
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Book Description
Author: T. S. R. Reddy
Publisher:
ISBN:
Category : Computer programs
Languages : en
Pages : 32
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Book Description
Author: Ho, J. C. C
Publisher:
ISBN:
Category :
Languages : en
Pages : 40
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Book Description
Author: J. S. Rao
Publisher: New Age International
ISBN: 9788122409772
Category : Rotors
Languages : en
Pages : 460
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Book Description
The Third Revised And Enlarged Edition Of The Book Presents An In-Depth Study Of The Dynamic Behaviour Of Rotating And Reciprocating Machinery. It Evolved Out Of Lectures Delivered At Different Universities Over The Last Two Decades. The Book Deals With Torsional And Bending Vibrations Of Rotors, Stability Aspects, Balancing And Condition Monitoring. Closed Form Solutions Are Given Wherever Possible And Parametric Studies Presented To Give A Clear Understanding Of The Subject. Transfer Matrix Methods Is Extensively Used For General Class Of Rotors For Both Bending And Torsional Vibrations.Special Attentions Are Given To Transient Analysis Of The Rotors Which Is Becoming An Essential Part Of The Design Of High Speed Machinery. Systems With Fluid Film Bearings, Cracked Rotors And Two Spool Rotors Are Also Presented.A First Course On Theory Of Vibration Is A Prerequisite To This Study. Analysis Used Is Fairly Simple, But Sufficiently Advanced To The Requisite Level Of Predicting Practical Observations. As Far As Possible, Practical Examples Are Illustrated, So That The Book Is Also Useful To Practising Engineers.A Special Feature Of This Book Is Diagnostics Of Rotating Machinery Using Vibration Signature Analysis And Application Of Expert Systems To A Field Engineer In Trouble Shooting Work.
Author: Robert Clark
Publisher: Springer Science & Business Media
ISBN: 1402021062
Category : Technology & Engineering
Languages : en
Pages : 770
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Book Description
In this new edition, the fundamental material on classical linear aeroelasticity has been revised. Also new material has been added describing recent results on the research frontiers dealing with nonlinear aeroelasticity as well as major advances in the modelling of unsteady aerodynamic flows using the methods of computational fluid dynamics and reduced order modeling techniques. New chapters on aeroelasticity in turbomachinery and aeroelasticity and the latter chapters for a more advanced course, a graduate seminar or as a reference source for an entrée to the research literature.
Author: Guang Fan Li
Publisher: Trans Tech Publications Ltd
ISBN: 3038139726
Category : Technology & Engineering
Languages : en
Pages : 2926
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Book Description
Volume is indexed by Thomson Reuters CPCI-S (WoS). The collection of peer reviewed papers covers all aspects of mechanics and materials: theoretical, experimental, and computational. Specific topics of interest include: mechanics of materials, rock and soil mechanics, fluid and heat mechanics, machine parts and mechanisms, composites, micro/nano materials, steel and alloys, and building materials and other related topics.
