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Experimental And Numerical Investigation Of Vortex Shedding Of A Representative Ucav Configuration For Vortex Flow Control
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Book Synopsis Experimental and Numerical Investigation of Vortex Shedding of a Representative UCAV Configuration for Vortex Flow Control by :
Download or read book Experimental and Numerical Investigation of Vortex Shedding of a Representative UCAV Configuration for Vortex Flow Control written by and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: On vehicles with swept wings, leading edge vortices are created at off-design conditions, Ref. 1. The leading edge vortex generally has a beneficial effect in the form of increased lift. By controlling the location of the shed vortex or vortices, vehicle roll and pitch control may be possible. Uninhabited Combat Air Vehicles (UCAV) that utilize stealth to avoid detection suffer a radar signature increase when control surfaces are deflected. Thus, there is an advantage to be gained by limiting flap deflection by utilizing vortex flow control to change vehicle attitude. In view of this, an experimental and numerical investigation was conducted on a representative UCAV configuration to define the flowfield and investigate methods to control vortex location, and ultimately, vehicle attitude. In view of this, a test program was carried out to identify the flow features of a representative UCAV configuration and utilize a simple blowing jet near the nose of the vehicle to attempt vortex flow control.
Book Synopsis Experimental and Numerical Investigation of Vortex Shedding by : Abubaker Awidat Salem
Download or read book Experimental and Numerical Investigation of Vortex Shedding written by Abubaker Awidat Salem and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental and Numerical Investigation of Vortex Flow Over a 76/60-deg Double-delta Wing by : J. E. J. Maseland
Download or read book Experimental and Numerical Investigation of Vortex Flow Over a 76/60-deg Double-delta Wing written by J. E. J. Maseland and published by . This book was released on 1992 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental Investigation of Vortex Shedding in High Reynolds Number Flow Over Compressor Blades in Cascade by : Choon P. Lim
Download or read book Experimental Investigation of Vortex Shedding in High Reynolds Number Flow Over Compressor Blades in Cascade written by Choon P. Lim and published by . This book was released on 2003-03 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation of vortex shedding downstream of a cascade of compressor stator blades, at off-design inlet-flow angles of 35, 33 and 31 degrees and Reynolds numbers, based on chord length, of 625,000, 750,000 and 800,000 is reported. The objective of the study was to characterize the flow and vortex shedding through blade surface pressure measurements and hot-wire anemometry. Vortex shedding was determined to be a leading edge phenomenon as periodic shedding was only detected on the pressure side of the wake, The relationship between vortex shedding frequency and Reynolds number was nearly linear. The vortex shedding frequency at three incidence angles was observed to be quite similar at lower Reynolds number (i.e. 450,000 and below) but developed into a larger scatter at higher Reynolds number. Similarly, the Strouhal numbers were observed to be fairly consistent (0.22 to 0.24) at low Reynolds number and more scattered (0.18 to 0.25) with increasing Reynolds number. The result obtained was comparable to the experimental results obtained by Roshko Ref. 14, for vortex shedding behind a circular cylinder.
Book Synopsis Experimental and Numerical Investigation of the Flow in the Core of a Leading Edge Vortex by : Nick G. Verhaagen
Download or read book Experimental and Numerical Investigation of the Flow in the Core of a Leading Edge Vortex written by Nick G. Verhaagen and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental and Numerical Studies of Vortex Shedding Flow Over a Circular Cylinder Near a Wall by : Chengwang Lei
Download or read book Experimental and Numerical Studies of Vortex Shedding Flow Over a Circular Cylinder Near a Wall written by Chengwang Lei and published by . This book was released on 2000 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 02-3155 - 02-3346 written by and published by . This book was released on 2002 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental Investigation of Vortex Shedding in Flow Over Second- Generation, Controlled-Diffusion, Compressor Blades in Cascade by : Peter J. Brown
Download or read book Experimental Investigation of Vortex Shedding in Flow Over Second- Generation, Controlled-Diffusion, Compressor Blades in Cascade written by Peter J. Brown and published by . This book was released on 2002-03 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation of vortex shedding downstream of a cascade of second-generation, controlled-diffusion, compressor stator blades, at off-design inlet-flow angles of 31, 33 and 35 degrees and Reynolds numbers, based on chord length, of 280,000, 380,000 and 640,000 is reported. The objective of the study was to characterize the flow and shedding through various complementary methods. Blade surface pressure measurements were taken from a fully instrumented blade, and distributions of pressure coefficients were determined. Five-hole probe wake surveys were performed at midspan, and the total pressure loss coefficients and axial velocity ratios were calculated. Upstream inlet-flow angle was set, and further characterized through two-component laser- Doppler velocimetry (LDV). Hot-wire anemometry measurements were performed at midspan, in the wake, and the reduced data were compared with two-component LDV surveys of the same regions. Plots of hot-wire vs. LDV turbulence data are reported in addition to power spectra documenting the shedding events. Vortex shedding was determined to be a leading edge phenomenon as periodic shedding was only detected on the pressure side of the wake. The frequency and magnitude of shedding were found to be independent of incidence angle, and to increase with Reynolds number at constant incidence angle. The Strouhal number, based on leading edge diameter, was found to be in the range of 0.23-0.26, which is comparable to that of vortex shedding behind a circular cylinder in the Reynolds number range tested.
Book Synopsis Vortex Flows and Related Numerical Methods by : J.T. Beale
Download or read book Vortex Flows and Related Numerical Methods written by J.T. Beale and published by Springer Science & Business Media. This book was released on 2013-04-18 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many important phenomena in fluid motion are evident in vortex flow, i.e., flows in which vortical structures are significant in determining the whole flow. This book, which consists of lectures given at a NATO ARW held in Grenoble (France) in June 1992, provides an up-to-date account of current research in the study of these phenomena by means of numerical methods and mathematical modelling. Such methods include Eulerian methods (finite difference, spectral and wavelet methods) as well as Lagrangian methods (contour dynamics, vortex methods) and are used to study such topics as 2- or 3-dimensional turbulence, vorticity generation by solid bodies, shear layers and vortex sheets, and vortex reconnection. For researchers and graduate students in computational fluid dynamics, numerical analysis, and applied mathematics.
Download or read book Fluid Vortices written by Beverley Green and published by Springer Science & Business Media. This book was released on 1995-03-31 with total page 916 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid Vortices is a comprehensive, up-to-date, research-level overview covering all salient flows in which fluid vortices play a significant role. The various chapters have been written by specialists from North America, Europe and Asia, making for unsurpassed depth and breadth of coverage. Topics addressed include fundamental vortex flows (mixing layer vortices, vortex rings, wake vortices, vortex stability, etc.), industrial and environmental vortex flows (aero-propulsion system vortices, vortex-structure interaction, atmospheric vortices, computational methods with vortices, etc.), and multiphase vortex flows (free-surface effects, vortex cavitation, and bubble and particle interactions with vortices). The book can also be recommended as an advanced graduate-level supplementary textbook. The first nine chapters of the book are suitable for a one-term course; chapters 10--19 form the basis for a second one-term course.
Book Synopsis Studies of Vortex Dominated Flows by : M. Yousuff Hussaini
Download or read book Studies of Vortex Dominated Flows written by M. Yousuff Hussaini and published by . This book was released on 1987 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the astrophysical scale of a swirling spiral galaxy, through the geophysical scale of a hurricane, down to the subatomic scale of elementary particles, vortical motion and vortex dynamics have played a profound role in our understanding of the physical world. Kuchemann referred to vortex dynamics as "the sinews and muscles of fluid motion. " In order to update our understanding of vortex dominated flows, NASA Langley Research Center and the Institute for Computer Applications in Science and Engineering (ICASE) conducted a workshop during July 9-11, 1985. The subject was broadly divided into five overlapping topics vortex dynamics, vortex breakdown, massive separation, vortex shedding from sharp leading edges and conically separated flows. Some of the experts in each of these areas were invited to provide an overview of the subject. This volume is the proceedings of the workshop and contains the latest, theoretical, numerical, and experimental work in the above-mentioned areas. Leibovich, Widnall, Moore and Sirovich discussed topics on the fundamentals of vortex dynamics, while Keller and Hafez treated the problem of vortex break down phenomena; the contributions of Smith, Davis and LeBalleur were in the area of massive separation and inviscid-viscous interactions, while those of Cheng, Hoeijmakers and Munnan dealt with sharp-leading-edge vortex flows; and Fiddes and Marconi represented the category of conical separated flows.
Book Synopsis An Experimental and Numerical Investigation Into Reacting Vortex Structures Associated with Unstable Combustion by : Donald William Kendrick
Download or read book An Experimental and Numerical Investigation Into Reacting Vortex Structures Associated with Unstable Combustion written by Donald William Kendrick and published by . This book was released on 1995 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental Investigation of Active Control of Bluff Body Vortex Shedding by : Ilteris Koc
Download or read book Experimental Investigation of Active Control of Bluff Body Vortex Shedding written by Ilteris Koc and published by . This book was released on 2008 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Experimental Investigation of Vortex Shedding from Rotating Circular Cylinders by : Jerome Francis Jaminet
Download or read book An Experimental Investigation of Vortex Shedding from Rotating Circular Cylinders written by Jerome Francis Jaminet and published by . This book was released on 1968 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Experimental Investigation Into the Effects of Turbulence on Vortex Shedding by : Richard W. Nanes
Download or read book An Experimental Investigation Into the Effects of Turbulence on Vortex Shedding written by Richard W. Nanes and published by . This book was released on 1967 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Vortex Methods and Vortex Motion by : Karl E. Gustafson
Download or read book Vortex Methods and Vortex Motion written by Karl E. Gustafson and published by SIAM. This book was released on 1991-01-01 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vortex methods have emerged as a new class of powerful numerical techniques to analyze and compute vortex motion. This book addresses the theoretical, numerical, computational, and physical aspects of vortex methods and vortex motion. Vortex phenomena in fluid flows and the experimental, theoretical, and numerical methods used to characterize them are discussed in reviews by leading experts. Extensive photographs and sample computer graphics are provided. The development of large vortex structure in fluid flow is responsible for some of the most fascinating aspects of fluid dynamics, such as mixing, shearing, transport, and instability. Such issues arise in a variety of flow regimes, ranging from fundamental mathematical questions in laminar, transitional, and turbulent flow to sophisticated engineering settings and devices.
Book Synopsis A Comprehensive Study of Vortex Asymmetry on Slender Bodies at High Angles of Incidence by : Roopesh Sampath Kumar
Download or read book A Comprehensive Study of Vortex Asymmetry on Slender Bodies at High Angles of Incidence written by Roopesh Sampath Kumar and published by . This book was released on 2021 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vortex asymmetry develops on slender bodies at high angles of incidence, leading to large side-forcesand yaw moments even in symmetrical flight conditions. This unexpected side force can be large for the control surfaces to produce a restoring moment, thereby affecting the vehicle's trajectory, maneuverability, and performance. Previous studies suggest that the presence of random micro-surface imperfections near the forebody tip, incurred due to the conventional machining process and its coupling with incoming freestream turbulence are the cause for vortex asymmetry. Vortex asymmetry and its control studies have been the subject of numerous experimental and numerical investigations beginning with simplified canonical configurations such as cones and cone-cylinders followed by slender bodies with fins resembling a typical projectile configuration. While previous studies on vortex asymmetry have provided a substantial knowledge base, several fundamental questions about the flow topology and characteristics of the vortices remain unanswered. The key knowledge gaps in the form of a few questions are: what is the effect of aftbody on the initiation and development of vortex asymmetry? What is the role of imperfections on the aftbody, and how do they enhance or suppress vortex asymmetry? What is the role of forebody to aftbody transition junction on vortex initiation and development? How does the forebody vortex-fin interaction alter the control surface effectiveness? To answer some of these questions as research objectives and improve the understanding of flow physics associated with slender bodies at high angles of incidence, a comprehensive experimental and numerical investigation was carried out and the results are presented here. The test configuration involves a long slender body with two interchangeable forebodies (a cone and a tangent ogive). To study the vortex-fin interactions, Army Navy Basic Finner (conecylinder with fins) and ogive-cylinder with fins were designed and tested. Experiments include force measurements using a six-component strain gauge balance, oil flow visualization, velocity and vorticity field measurements using particle image velocimetry. Results show that a pair of counterrotating, nearly-symmetric vortices develop over a polished cone but those become asymmetric over the cylinder. Several secondary shear-layer vortices form at the cone-cylinder junction and over the aftbody due to sharp turn angle (a change on pressure boundary), surface imperfections, and various surface joints. These secondary shear-layer vortices then merge with the primary forebody vortex pair, leading to the flow asymmetry. The flow characteristics and side-forces vary significantly when the conical forebody is rotated about its axis of symmetry and set to different azimuthal positions. The results strongly suggest that a change in the geometry at the cone-cylinder junction and surface imperfections present on the cylindrical aftbody plays a critical role in determining the overall flowasymmetry and the side force magnitude. The effect of forebody change has a significant impact on the flow field development. The peak vorticity, circulation, and trajectory of primary vortices for ogive-cylinder configuration indicate a notable change in both magnitude and location when compared to cone-cylinder configuration. The results show that the formation of secondary shearlayer vortices can be minimized by eliminating the sudden change in geometry and smoothing the surface imperfections. The absence of secondary shear-layer vortices resulted in relatively low levels of side forces for the ogive-cylinder configuration as compared to the cone-cylinder. In the case of vortex-fin interaction investigations, results show that the basic aerodynamic characteristics remain invariant with roll orientation at low angles of incidence. At high angles of incidence, fin orientation plays a significant role in dictating the body's aerodynamic forces. At low angles of incidence, the forebody vortices are symmetric and remain close to the body, and interact with the control surfaces. The forebody vortex interaction seems to be influenced by the body roll orientation. The pressure distributions over the fin surfaces, and in turn, the fins' control effectiveness is significantly affected by the interaction of forebody vortices. At high angles of incidence, the vortices become highly asymmetric, where one vortex is closer to the fins and the other vortex lifted away from the fins. Under such an instance, the resulting pressure distribution is uneven and lead to the generation of side forces and adverse yaw moments. To summarize, the present study has significantly improved the fundamental understanding of vortex flows on slender bodies at high angles of incidence. In particular, it has answered the role of secondary vortices on the development of overall vortex asymmetry and its interaction with control surfaces. The outcome of this study will help guide the design of next-generation projectiles expected to perform maneuvers at high angles of incidence. The high-fidelity experimental database generated over a range of test conditions will be very useful to validate physics based simulation tools being developed at Army Research Laboratory. The present study was focused at low-speeds and incompressible flows and therefore it is suggested that future studies must investigate the effect of compressibility on vortex asymmetry. Also, time-resolved measurements are recommended to understand the role of vortex dynamics on the slender body.
