Jet noise physics and modeling using firstprinciples simulations

Jet noise physics and modeling using firstprinciples simulations PDF Author:
Publisher: DIANE Publishing
ISBN: 1428995218
Category :
Languages : en
Pages : 47

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Jet noise physics and modeling using firstprinciples simulations

Jet noise physics and modeling using firstprinciples simulations PDF Author:
Publisher: DIANE Publishing
ISBN: 1428995218
Category :
Languages : en
Pages : 47

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Book Description


Jet Noise Physics and Modeling Using First-Principles Simulations

Jet Noise Physics and Modeling Using First-Principles Simulations PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 50

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Jet Noise Physics and Modeling Using First-Principles Simulations

Jet Noise Physics and Modeling Using First-Principles Simulations PDF Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781720606628
Category :
Languages : en
Pages : 48

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Book Description
An extensive analysis of our jet DNS database has provided for the first time the complex correlations that are the core of many statistical jet noise models, including MGBK. We have also for the first time explicitly computed the noise from different components of a commonly used noise source as proposed in many modeling approaches. Key findings are: (1) While two-point (space and time) velocity statistics are well-fitted by decaying exponentials, even for our low-Reynolds-number jet, spatially integrated fourth-order space/retarded-time correlations, which constitute the noise "source" in MGBK, are instead well-fitted by Gaussians. The width of these Gaussians depends (by a factor of 2) on which components are considered. This is counter to current modeling practice, (2) A standard decomposition of the Lighthill source is shown by direct evaluation to be somewhat artificial since the noise from these nominally separate components is in fact highly correlated. We anticipate that the same will be the case for the Lilley source, and (3) The far-field sound is computed in a way that explicitly includes all quadrupole cancellations, yet evaluating the Lighthill integral for only a small part of the jet yields a far-field noise far louder than that from the whole jet due to missing nonquadrupole cancellations. Details of this study are discussed in a draft of a paper included as appendix A.Freund, Jonathan B.Glenn Research CenterDIRECT NUMERICAL SIMULATION; JET AIRCRAFT NOISE; MATHEMATICAL MODELS; AEROACOUSTICS; FLOW DISTRIBUTION; COMPUTATIONAL FLUID DYNAMICS; LOW REYNOLDS NUMBER; FAR FIELDS; QUADRUPOLES; NOZZLE DESIGN; NOISE PREDICTION (AIRCRAFT); TURBULENT FLOW; RANDOM NOISE

Unsteady Computational Fluid Dynamics in Aeronautics

Unsteady Computational Fluid Dynamics in Aeronautics PDF Author: P.G. Tucker
Publisher: Springer Science & Business Media
ISBN: 9400770499
Category : Technology & Engineering
Languages : en
Pages : 432

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Book Description
The field of Large Eddy Simulation (LES) and hybrids is a vibrant research area. This book runs through all the potential unsteady modelling fidelity ranges, from low-order to LES. The latter is probably the highest fidelity for practical aerospace systems modelling. Cutting edge new frontiers are defined. One example of a pressing environmental concern is noise. For the accurate prediction of this, unsteady modelling is needed. Hence computational aeroacoustics is explored. It is also emerging that there is a critical need for coupled simulations. Hence, this area is also considered and the tensions of utilizing such simulations with the already expensive LES. This work has relevance to the general field of CFD and LES and to a wide variety of non-aerospace aerodynamic systems (e.g. cars, submarines, ships, electronics, buildings). Topics treated include unsteady flow techniques; LES and hybrids; general numerical methods; computational aeroacoustics; computational aeroelasticity; coupled simulations and turbulence and its modelling (LES, RANS, transition, VLES, URANS). The volume concludes by pointing forward to future horizons and in particular the industrial use of LES. The writing style is accessible and useful to both academics and industrial practitioners. From the reviews: "Tucker's volume provides a very welcome, concise discussion of current capabilities for simulating and modellng unsteady aerodynamic flows. It covers the various pos sible numerical techniques in good, clear detail and presents a very wide range of practical applications; beautifully illustrated in many cases. This book thus provides a valuable text for practicing engineers, a rich source of background information for students and those new to this area of Research & Development, and an excellent state-of-the-art review for others. A great achievement." Mark Savill FHEA, FRAeS, C.Eng, Professor of Computational Aerodynamics Design & Head of Power & Propulsion Sciences, Department of Power & Propulsion, School of Engineering, Cranfield University, Bedfordshire, U.K. "This is a very useful book with a wide coverage of many aspects in unsteady aerodynamics method development and applications for internal and external flows." L. He, Rolls-Royce/RAEng Chair of Computational Aerothermal Engineering, Oxford University, U.K. "This comprehensive book ranges from classical concepts in both numerical methods and turbulence modelling approaches for the beginner to latest state-of-the-art for the advanced practitioner and constitutes an extremely valuable contribution to the specific Computational Fluid Dynamics literature in Aeronautics. Student and expert alike will benefit greatly by reading it from cover to cover." Sébastien Deck, Onera, Meudon, France

Control of Jet Noise Through Mixing Enhancement

Control of Jet Noise Through Mixing Enhancement PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 18

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Aerodynamic Design of Transport Aircraft

Aerodynamic Design of Transport Aircraft PDF Author: E. Obert
Publisher: IOS Press
ISBN: 1607504073
Category : Science
Languages : en
Pages : 656

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Book Description
The origin of Aerodynamic Design of Transport Aircraft stems from the time when the author was appointed part-time professor in the Aerospace Faculty of Delft University of Technology. At the time his main activities were those of leading the departments of Aerodynamics, Performance and Preliminary Design at Fokker Aircraft Company. The groundwork for this book started in 1987 as a series of lecture notes consisting mainly of pictorial material with a minimum of English explanatory text. After the demise of Fokker in 1996 one feared that interest in aeronautical engineering would strongly diminish. As a result of this, the course was discontinued and the relationship between the author and the faculty came to an end. Two years later the situation was reappraised, and the interest in aeronautical engineering remained, so the course was reinstated with a former Fokker colleague Ronald Slingerland as lecturer. The lecture notes from these courses form the foundation of this publication.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 692

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Proceedings of the ... ASME/JSME Joint Fluids Engineering Conference

Proceedings of the ... ASME/JSME Joint Fluids Engineering Conference PDF Author:
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 776

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Complex Effects in Large Eddy Simulations

Complex Effects in Large Eddy Simulations PDF Author: Stavros Kassinos
Publisher: Springer Science & Business Media
ISBN: 3540342346
Category : Technology & Engineering
Languages : en
Pages : 440

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Book Description
The field of Large Eddy Simulations is reaching a level of maturity that brings this approach to the mainstream of engineering computations, while it opens opportunities and challenges. The main objective of this volume is to bring together leading experts in presenting the state-of-the-art and emerging approaches for treating complex effects in LES. A common theme throughout is the role of LES in the context of multiscale modeling and simulation.

Knowledge Guided Machine Learning

Knowledge Guided Machine Learning PDF Author: Anuj Karpatne
Publisher: CRC Press
ISBN: 1000598101
Category : Business & Economics
Languages : en
Pages : 442

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Book Description
Given their tremendous success in commercial applications, machine learning (ML) models are increasingly being considered as alternatives to science-based models in many disciplines. Yet, these "black-box" ML models have found limited success due to their inability to work well in the presence of limited training data and generalize to unseen scenarios. As a result, there is a growing interest in the scientific community on creating a new generation of methods that integrate scientific knowledge in ML frameworks. This emerging field, called scientific knowledge-guided ML (KGML), seeks a distinct departure from existing "data-only" or "scientific knowledge-only" methods to use knowledge and data at an equal footing. Indeed, KGML involves diverse scientific and ML communities, where researchers and practitioners from various backgrounds and application domains are continually adding richness to the problem formulations and research methods in this emerging field. Knowledge Guided Machine Learning: Accelerating Discovery using Scientific Knowledge and Data provides an introduction to this rapidly growing field by discussing some of the common themes of research in KGML using illustrative examples, case studies, and reviews from diverse application domains and research communities as book chapters by leading researchers. KEY FEATURES First-of-its-kind book in an emerging area of research that is gaining widespread attention in the scientific and data science fields Accessible to a broad audience in data science and scientific and engineering fields Provides a coherent organizational structure to the problem formulations and research methods in the emerging field of KGML using illustrative examples from diverse application domains Contains chapters by leading researchers, which illustrate the cutting-edge research trends, opportunities, and challenges in KGML research from multiple perspectives Enables cross-pollination of KGML problem formulations and research methods across disciplines Highlights critical gaps that require further investigation by the broader community of researchers and practitioners to realize the full potential of KGML