Direct Computations Of A Synthetic Jet Actuator

DOWNLOAD

Download Direct Computations Of A Synthetic Jet Actuator PDF/ePub or read online books in Mobi eBooks. Click Download or Read Online button to get Direct Computations Of A Synthetic Jet Actuator book now. This website allows unlimited access to, at the time of writing, more than 1.5 million titles, including hundreds of thousands of titles in various foreign languages. If the content not found or just blank you must refresh this page

Direct Computations Of A Synthetic Jet Actuator

DOWNLOAD
Author : Declan Hayes-McCoy
language : en
Publisher:
Release Date : 2012

Direct Computations Of A Synthetic Jet Actuator written by Declan Hayes-McCoy and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.

Synthetic jet actuators have previously been defined as having potential use in both internal and external aerodynamic applications. The formation of a jet flow perpendicular to the surface of an aerofoil or in a duct of diffuser has a range of potential flow control benefits. These benefits can include both laminar to turbulent transition control, which is associated with a drag reduction in aerodynamic applications. The formation and development of zero-net-mass-flux synthetic jets are investigated using highly accurate numerical methods associated with the methodology of Direct Numerical Simulation (DNS). Jet formation is characterised by an oscillating streamwise jet centreline velocity, showing net momentum flux away from the jet orifice. This momentum flux away from the orifice takes the form of a series of vortex structures, often referred to as a vortex train. Numerical simulations of the synthetic jet actuator consist of a modified oscillating velocity profile applied to a wall boundary. The Reynolds numbers used vary from 85 ≤ Re ≤ 300. A complete numerical study of both axisymmetric and fully three-dimensional jet flow is performed. A parametric axisymmetric simulation is carried out in order to study the formation criterion and evolution of zero-net-mass-flux synthetic jets under variations in actuator input parameters. From the results of these simulations the conditions necessary for the formation of the synthetic jet along with the input parameters that provide an optimal jet output are deduced. Jet optimisation is defined by the mass flow, vortex strength and longevity of the vortex train as it travels downstream. Further investigations are carried out on a fully three-dimensional DNS version of the optimised axisymmetric case. Comparisons between the jet evolution and flow-field structures present in both the axisymmetric and three-dimensional configurations are made. This thesis examines the vortex structures, the jet centreline velocities along with time dependent and time averaged results in order to deduce and visualise the effects of the input parameters on the jet formation and performance. The results attained on altering the oscillation frequency of the jet actuator indicated that synthetic jets with zero mean velocity at the inflow behave significantly differently from jets with non-zero mean velocity at the inflow. A study into the evolution and formation of the train of vortex structures associated with the formation of a synthetic jet is performed. This study is accompanied with a series of time averaged results showing time dependent flow-field trends. The time history of the jet centreline velocity, showing the net momentum flux of the fluid away from the orifice of a fully developed synthetic jet, is analysed for both axisymmetric and three-dimensional cases. Differences in the fluid dynamics between the idealised axisymmetric configuration and the three-dimensional case have been identified, where three-dimensional effects are found to be important in the region near the jet nozzle exit. The effect of a disturbance introduced into the three-dimensional simulation in order to break its inherent symmetry around the jet centreline is examined by altering the input frequency of the disturbance. It was found that the effect of this relatively minor disturbance had a major effect on the jet flow field in the region adjacent to the orifice. The effect of which was deemed to be caused by discontinuities in the surface of the jet orifice due to manufacturing tolerances. Although the effects of these disturbances on the jet flow-field are large, they seem to have been neglected from numerical simulations to date. The effect of a synthetic jet on an imposed cross-streamwise velocity profile was examined. It was found that the synthetic jet flow-field resulted in a deformation of the velocity profile in the region downstream of the synthetic jet. It is suggested that this region of deformed flow could interact with coherent structures in a transitional boundary layer in order to delay flow transition to turbulence. The effect of varying the Strouhal number of a synthetic jet in a cross-flow is also analysed. It is clear from the results presented that, in the presence of a cross-flow velocity the Strouhal number effect on the synthetic jet flow field evolution, while dominant in a quiescent fluid is surpassed by the effect of the cross-flow.

Time Accurate Computations Of Free Flight Aerodynamics Of A Spinning Projectile With And Without Flow Control

DOWNLOAD
Author : Jabaraj Sahu
language : en
Publisher:
Release Date : 2006

Time Accurate Computations Of Free Flight Aerodynamics Of A Spinning Projectile With And Without Flow Control written by Jabaraj Sahu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with Aerodynamics categories.

This report describes a new multi-disciplinary computational study undertaken to compute the flight trajectories and simultaneously predict the unsteady free flight aerodynamics of a spinning projectile configuration with and without aerodynamic flow control. Actual flight trajectories are computed with an advanced coupled computational fluid dynamics (CFD)-rigid body dynamics (RBD) technique. An advanced time-accurate Navier-Stokes computational technique has been used in CFD to compute the unsteady aerodynamics associated with the free flight of the spinning projectile at subsonic speeds. Computed positions and orientations of the projectile have been compared with actual data measured from free flight tests and are found to be generally in good agreement. The same advanced coupled procedure has been used to compute the aerodynamics of the spinning projectile with flow control with the use of a synthetic microjet. Unsteady numerical results obtained from the coupled method show the flow field, the aerodynamic forces and moments, and the flight trajectories of the projectile.

Direct And Large Eddy Simulation Vi

DOWNLOAD
Author : E. Lamballais
language : en
Publisher: Springer Science & Business Media
Release Date : 2006-10-19

Direct And Large Eddy Simulation Vi written by E. Lamballais and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006-10-19 with Technology & Engineering categories.

The sixth ERCOFTAC Workshop on ‘Direct and Large-Eddy Simulation’ (DLES-6) was held at the University of Poitiers from September 12-14, 2005. Following the tradition of previous workshops in the DLES-series, this edition has reflected the state-of-the-art of numerical simulation of transitional and turbulent flows and provided an active forum for discussion of recent developments in simulation techniques and understanding of flow physics.

Parallel Computational Fluid Dynamics 2006

DOWNLOAD
Author : Jang-Hyuk Kwon
language : en
Publisher: Elsevier
Release Date : 2007-09-12

Parallel Computational Fluid Dynamics 2006 written by Jang-Hyuk Kwon and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007-09-12 with Computers categories.

The proceedings from Parallel CFD 2006 covers all aspects of parallel computings and its applications. Although CFD is one of basic tools for design procedures to produce machineries, such as automobiles, ships, aircrafts, etc., large scale parallel computing has been realized very recently, especially for the manufactures. Various applications in many areas could be experienced including acoustics, weather prediction and ocean modeling, flow control, turbine flow, fluid-structure interaction, optimization, heat transfer, hydrodynamics.- Report on current research in the field in an area which is rapidly changing - Subject is important to all interested in solving large fluid dynamics problems - Interdisciplinary activity. Contributions include scientists with a variety of backgrounds

The Proceedings Of 2023 4th International Symposium On Insulation And Discharge Computation For Power Equipment Idcompu2023

DOWNLOAD
Author : Xuzhu Dong
language : en
Publisher: Springer Nature
Release Date : 2024-01-19

The Proceedings Of 2023 4th International Symposium On Insulation And Discharge Computation For Power Equipment Idcompu2023 written by Xuzhu Dong and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024-01-19 with Technology & Engineering categories.

This book includes original, peer-reviewed research papers from the 2023 4th International Symposium on Insulation and Discharge Computation for Power Equipment (IDCOMPU2023), held in Wuhan, China. The topics covered include but are not limited to: insulation, discharge computations, electric power equipment, and electrical materials. The papers share the latest findings in the field of insulation and discharge computations of electric power equipment, making the book a valuable asset for researchers, engineers, university students, etc.

Vortex Rings And Jets

DOWNLOAD
Author : Daniel T. H. New
language : en
Publisher: Springer
Release Date : 2015-03-26

Vortex Rings And Jets written by Daniel T. H. New and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015-03-26 with Technology & Engineering categories.

In this book, recent developments in our understanding of fundamental vortex ring and jet dynamics will be discussed, with a view to shed light upon their near-field behaviour which underpins much of their far-field characteristics. The chapters provide up-to-date research findings by their respective experts and seek to link near-field flow physics of vortex ring and jet flows with end-applications in mind. Over the past decade, our knowledge on vortex ring and jet flows has grown by leaps and bounds, thanks to increasing use of high-fidelity, high-accuracy experimental techniques and numerical simulations. As such, we now have a much better appreciation and understanding on the initiation and near-field developments of vortex ring and jet flows under many varied initial and boundary conditions. Chapter 1 outlines the vortex ring pinch-off phenomenon and how it relates to the initial stages of jet formations and subsequent jet behaviour, while Chapter 2 takes a closer look at the behaviour resulting from vortex ring impingement upon solid boundaries and how the use of a porous surface alters the impingement process. Chapters 3 and 4 focus upon the formation of synthetic jets from vortex ring structures experimentally and numerically, the challenges in understanding the relationships between their generation parameters and how they can be utilized in flow separation control problems. Chapter 5 looks at the use of imposing selected nozzle trailing-edge modifications to effect changes upon the near-field dynamics associated with circular, noncircular and coaxial jets, with a view to control their mixing behaviour. And last but not least, Chapter 6 details the use of unique impinging jet configurations and how they may lend themselves towards greater understanding and operating efficacies in heat transfer problems. This book will be useful to postgraduate students and researchers alike who wish to get up to speed regarding the latest developments in vortex ring and jet flow behaviour and how their interesting flow dynamics may be put into good use in their intended applications.

30th Aiaa Fluid Dynamics Conference

DOWNLOAD
Author :
language : en
Publisher:
Release Date : 1999

30th Aiaa Fluid Dynamics Conference written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1999 with Fluid dynamics categories.

Synthetic Jets

DOWNLOAD
Author : Kamran Mohseni
language : en
Publisher: CRC Press
Release Date : 2014-09-17

Synthetic Jets written by Kamran Mohseni and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-09-17 with Science categories.

Compiles Information from a Multitude of SourcesSynthetic jets have been used in numerous applications, and are part of an emergent field. Accumulating information from hundreds of journal articles and conference papers, Synthetic Jets: Fundamentals and Applications brings together in one book the fundamentals and applications of fluidic actuators.

Adaptive Compensation Of Nonlinear Actuators For Flight Control Applications

DOWNLOAD
Author : Dipankar Deb
language : en
Publisher: Springer Nature
Release Date : 2021-07-22

Adaptive Compensation Of Nonlinear Actuators For Flight Control Applications written by Dipankar Deb and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-07-22 with Technology & Engineering categories.

This book provides a basic understanding of adaptive control and its applications in Flight control. It discusses the designing of an adaptive feedback control system and analyzes this for flight control of linear and nonlinear aircraft models using synthetic jet actuators. It also discusses control methodologies and the application of control techniques which will help practicing flight control and active flow control researchers. It also covers modelling and control designs which will also benefit researchers from the background of fluid mechanics and health management of actuation systems. The unique feature of this book is characterization of synthetic jet actuator nonlinearities over a wide range of angles of attack, an adaptive compensation scheme for such nonlinearities, and a systematic framework for feedback control of aircraft dynamics with synthetic jet actuators.

Unsteady Numerical Simulations Of Subsonic Flow Over A Projectile With Jet Interaction

DOWNLOAD
Author : Jabaraj Sahu
language : en
Publisher:
Release Date : 2003

Unsteady Numerical Simulations Of Subsonic Flow Over A Projectile With Jet Interaction written by Jabaraj Sahu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with Aerodynamics categories.

This report describes a computational study undertaken to consider the aerodynamic effect of synthetic jets as a means to provide the control authority needed to maneuver a projectile at low subsonic speeds. The time-accurate Navier-Stokes computational technique has been used to obtain numerical solutions for the unsteady jet interaction flow field for a projectile at a subsonic speed, Mach = 0.11, and several angles of attack from O deg to 4 deg. Qualitative flow field features show the interaction of the time dependent jet with the free stream flow. Numerical results show the effect of the jet on the flow field, surface pressures and aerodynamic coefficients. Unsteady numerical results have been obtained for a two-dimensional jet flow and compared with experimental data for validation. The same unsteady jet modeling technique has been applied to a subsonic projectile. These numerical results are being assessed to determine if synthetic jets can be used to provide the control authority needed for maneuvering munitions to hit the targets with precision.