Download or read book Adjoint based Aeroacoustic Control written by and published by . This book was released on 2006 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: A technique for controlling complex unsteady high-speed flows is being developed. Our approach uses numerical solutions of the adjoint of the compressible flow equations to circumvent the complexity of the flow and directly determine the sensitivity of a specified control objective to changes in actuation. Since this method requires a complete physical description of a turbulent flow which is only currently available from direct numerical simulations, the immediate objective obviously is not to develop a practical control scheme. Instead, the method's utility is in its ability to study flow control in applications like jet noise reduction where a practical prediction capability is lacking. It provides working controls which can be generalized and at the same time provides unique full-fidelity simulation databases of a noisy and its corresponding quieted flow, which can be compared to study the subtle mechanisms of sound generation. The key result of the previous funding period was the development of the adjoint-based formulation in two-dimensions and its (remarkably) successful demonstration on a two-dimensional mixing layer. That was the first time a non-trial-and-error methodology successfully reduced noise from a free shear flow to The summary of our accomplishments of this funding period.
Download or read book Towards Adjoint based Methods for Aeroacoustic Control written by S. Scott Collis and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optimal Control of Complex Structures written by K.-H. Hoffmann and published by Birkhäuser. This book was released on 2012-12-06 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interest in the area of control of systems defined by partial differential Equations has increased strongly in recent years. A major reason has been the requirement of these systems for sensible continuum mechanical modelling and optimization or control techniques which account for typical physical phenomena. Particular examples of problems on which substantial progress has been made are the control and stabilization of mechatronic structures, the control of growth of thin films and crystals, the control of Laser and semi-conductor devices, and shape optimization problems for turbomachine blades, shells, smart materials and microdiffractive optics. This volume contains original articles by world reknowned experts in the fields of optimal control of partial differential equations, shape optimization, numerical methods for partial differential equations and fluid dynamics, all of whom have contributed to the analysis and solution of many of the problems discussed. The collection provides a state-of-the-art overview of the most challenging and exciting recent developments in the field. It is geared towards postgraduate students and researchers dealing with the theoretical and practical aspects of a wide variety of high technology problems in applied mathematics, fluid control, optimal design, and computer modelling.
Download or read book Adjoint based control and optimization of aerodynamic flows written by Mattias Chevalier and published by . This book was released on 2002 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Perspectives in Flow Control and Optimization written by Max D. Gunzburger and published by SIAM. This book was released on 2003-01-01 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduces several approaches for solving flow control and optimization problems through the use of modern methods.
Download or read book Semismooth Newton Methods for Variational Inequalities and Constrained Optimization Problems in Function Spaces written by Michael Ulbrich and published by SIAM. This book was released on 2011-01-01 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semismooth Newton methods are a modern class of remarkably powerful and versatile algorithms for solving constrained optimization problems with partial differential equations (PDEs), variational inequalities, and related problems. This book provides a comprehensive presentation of these methods in function spaces, striking a balance between thoroughly developed theory and numerical applications. Although largely self-contained, the book also covers recent developments in the field, such as state-constrained problems, and offers new material on topics such as improved mesh independence results. The theory and methods are applied to a range of practically important problems, including: optimal control of nonlinear elliptic differential equations, obstacle problems, and flow control of instationary Navier-Stokes fluids. In addition, the author covers adjoint-based derivative computation and the efficient solution of Newton systems by multigrid and preconditioned iterative methods.
Download or read book Advanced Computational Methods and Design for Greener Aviation written by Tero Tuovinen and published by Springer Nature. This book was released on with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 3rd Theoretical Fluid Mechanics Meeting written by and published by . This book was released on 2002 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2008 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acoustics written by Allan D. Pierce and published by Springer. This book was released on 2019-06-22 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt: This corrected version of the landmark 1981 textbook introduces the physical principles and theoretical basis of acoustics with deep mathematical rigor, concentrating on concepts and points of view that have proven useful in applications such as noise control, underwater sound, architectural acoustics, audio engineering, nondestructive testing, remote sensing, and medical ultrasonics. Since its publication, this text has been used as part of numerous acoustics-related courses across the world, and continues to be used widely today. During its writing, the book was fine-tuned according to insights gleaned from a broad range of classroom settings. Its careful design supports students in their pursuit of a firm foundation while allowing flexibility in course structure. The book can easily be used in single-term or full-year graduate courses and includes problems and answers. This rigorous and essential text is a must-have for any practicing or aspiring acoustician.
Download or read book Multi model Simulation for Optimal Control of Aeroacoustics written by and published by . This book was released on 2005 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flow-generated noise, especially rotorcraft noise has been a serious concern for bothcommercial and military applications. A particular important noise source for rotor-craft is Blade-Vortex-Interaction (BVI)noise, a high amplitude, impulsive sound thatoften dominates other rotorcraft noise sources. Usually BVI noise is caused by theunsteady flow changes around various rotor blades due to interactions with vorticespreviously shed by the blades. A promising approach for reducing the BVI noise isto use on-blade controls, such as suction/blowing, micro-flaps/jets, and smart struc-tures. Because the design and implementation of such experiments to evaluate suchsystems are very expensive, efficient computational tools coupled with optimal con-trol systems are required to explore the relevant physics and evaluate the feasibilityof using various micro-fluidic devices before committing to hardware. In this thesis the research is to formulate and implement efficient computationaltools for the development and study of optimal control and design strategies for com-plex flow and acoustic systems with emphasis on rotorcraft applications, especiallyBVI noise control problem. The main purpose of aeroacoustic computations is todetermine the sound intensity and directivity far away from the noise source. How-ever, the computational cost of using a high-fidelity flow-physics model across thefull domain is usually prohibitive and itmight also be less accurate because of thenumerical diffusion and other problems. Taking advantage of the multi-physics andmulti-scale structure of this aeroacoustic problem, we develop a multi-model, multi-domain (near-field/far-field) method based on a discontinuous Galerkin discretiza-tion. In this approach the coupling of multi-domains and multi-models is achievedby weakly enforcing continuity of normal fluxes across a coupling surface. For ourinterested aeroacoustics control problem, the adjoint equations that determine thesensitivity of the cost functional to changes in control are also solved with same ap-proach by weakly enforcing continuity ofnormal fluxes across a coupling surface. Such formulations have been validated extensively for several aeroacoustics state andcontrol problems. A multi-model based optimal control framework has been constructed and ap-plied to our interested BVI noise control problem. This model problem consists ofthe interaction of a compressible vortex with Bell AH-1 rotor blade with wall-normal3 velocity used as control on the rotor blade surface. The computational domain isdecomposed into the near-field and far-field. The near-field is obtained by numericalsolution of the Navier-Stokes equations while far away from the noise source, wherethe effect of nonlinearities is negligible, the linearized Euler equations are used tomodel the acoustic wave propagation. The BVI wave packet is targeted by definingan objective function that measures the square amplitude of pressure fluctuations inan observation region, at a time interval encompassing the dominant leading edgecompressibility waves. Our control results show that a 12dB reduction in the ob-servation region is obtained. Interestingly, the control mechanism focuses on theobservation region and only minimize the sound level in that region at the expense ofother regions. The vortex strength and trajectory get barely changed. However, theoptimal control does alter the interaction of the vortical and potential fields, whichis the source of BVI noise. While this results in a slight increase in drag, there is asignificant reduction in the temporal gradient of lift leading to a reduction in BVIsound levels. 4.
Download or read book Fluid Structure Sound Interactions and Control written by Marianna Braza and published by Springer Nature. This book was released on 2021-05-05 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains a thorough and unique record of recent advances in the important scientific fields fluid–structure interaction, acoustics and control of priority interest in the academic community and also in an industrial context regarding new engineering designs. It updates advances in these fields by presenting state-of-the-art developments and achievements since the previous Book published by Springer in 2018 after the 4th FSSIC Symposium. This book is unique within the related literature investigating advances in these fields because it addresses them in a complementary way and thereby enhances cross-fertilization between them, whereas other books treat these fields separately.
Download or read book Advances in Evolutionary and Deterministic Methods for Design Optimization and Control in Engineering and Sciences written by António Gaspar-Cunha and published by Springer Nature. This book was released on 2020-11-23 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents improved and extended versions of selected papers from EUROGEN 2019, a conference with interest on developing or applying evolutionary and deterministic methods in optimization of design and emphasizing on industrial and societal applications.
Download or read book Advances in Evolutionary and Deterministic Methods for Design Optimization and Control in Engineering and Sciences written by David Greiner and published by Springer. This book was released on 2014-11-14 with total page 511 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains state-of-the-art contributions in the field of evolutionary and deterministic methods for design, optimization and control in engineering and sciences. Specialists have written each of the 34 chapters as extended versions of selected papers presented at the International Conference on Evolutionary and Deterministic Methods for Design, Optimization and Control with Applications to Industrial and Societal Problems (EUROGEN 2013). The conference was one of the Thematic Conferences of the European Community on Computational Methods in Applied Sciences (ECCOMAS). Topics treated in the various chapters are classified in the following sections: theoretical and numerical methods and tools for optimization (theoretical methods and tools; numerical methods and tools) and engineering design and societal applications (turbo machinery; structures, materials and civil engineering; aeronautics and astronautics; societal applications; electrical and electronics applications), focused particularly on intelligent systems for multidisciplinary design optimization (mdo) problems based on multi-hybridized software, adjoint-based and one-shot methods, uncertainty quantification and optimization, multidisciplinary design optimization, applications of game theory to industrial optimization problems, applications in structural and civil engineering optimum design and surrogate models based optimization methods in aerodynamic design.
Download or read book Aeroacoustic Measurements written by T. J. Mueller and published by Springer Science & Business Media. This book was released on 2002-08-07 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book describes recent developments in aeroacoustic measurements in wind tunnels and the interpretation of the resulting data. The reader will find the latest measurement techniques described along with examples of the results.
Download or read book Computational Aeroacoustics written by Jay C. Hardin and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 525 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational aeroacoustics is rapidly emerging as an essential element in the study of aerodynamic sound. As with all emerging technologies, it is paramount that we assess the various opportuni ties and establish achievable goals for this new technology. Essential to this process is the identification and prioritization of fundamental aeroacoustics problems which are amenable to direct numerical siIn ulation. Questions, ranging from the role numerical methods play in the classical theoretical approaches to aeroacoustics, to the correct specification of well-posed numerical problems, need to be answered. These issues provided the impetus for the Workshop on Computa tional Aeroacoustics sponsored by ICASE and the Acoustics Division of NASA LaRC on April 6-9, 1992. The participants of the Work shop were leading aeroacousticians, computational fluid dynamicists and applied mathematicians. The Workshop started with the open ing remarks by M. Y. Hussaini and the welcome address by Kristin Hessenius who introduced the keynote speaker, Sir James Lighthill. The keynote address set the stage for the Workshop. It was both an authoritative and up-to-date discussion of the state-of-the-art in aeroacoustics. The presentations at the Workshop were divided into five sessions - i) Classical Theoretical Approaches (William Zorumski, Chairman), ii) Mathematical Aspects of Acoustics (Rodolfo Rosales, Chairman), iii) Validation Methodology (Allan Pierce, Chairman), iv) Direct Numerical Simulation (Michael Myers, Chairman), and v) Unsteady Compressible Flow Computa tional Methods (Douglas Dwoyer, Chairman).
Download or read book Optimal Control of Salinity in the Sacramento San Joaquin Delta written by Eli Sava Ateljevich and published by . This book was released on 2001 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:
