Download or read book Crossflow Vortex Breakdown on Swept Wings written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The spatial evolution of cross flow-vortex packets in a laminar boundary layer on a swept wing are computed by the direct numerical simulation of the incompressible Navier- Stokes equations. A wall-normal velocity distribution of steady suction and blowing at the wing surface is used to generate a strip of equally spaced and periodic disturbances along the span. Three simulations are conducted to study the effect of initial amplitude on the disturbance evolution, to determine the role of traveling cross ow modes in transition, and to devise a correlation function to guide theories of transition prediction. In each simulation, the vortex packets first enter a chordwise region of linear independent growth, then, the individual packets coalesce downstream and interact with adjacent packets, and, finally, the vortex packets nonlinearly interact to generate inflectional velocity profiles. As the initial amplitude of the disturbance is increased, the length of the evolution to breakdown decreases. For this pressure gradient, stationary modes dominate the disturbance evolution. A two-coeffcient function was devised to correlate the simulation results. The coefficients, combined with a single simulation result, provide sufficient information to generate the evolution pattern for disturbances of any initial amplitude. Joslin, R. D. and Streett, C. L. Langley Research Center ...
Download or read book Analytical studies of separated vortex flow on highly swept wings written by John M. Kuhlman and published by . This book was released on 1978 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vortex Flow Aerodynamics written by James Franklin Campbell and published by . This book was released on 1986 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vortex Flow Aerodynamics Volume 1 written by James F. Campbell and published by . This book was released on 1986 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental and Analytical Studies of Separated Vortex Flow on Highly Swept Wings written by John M. Kuhlman and published by . This book was released on 1977 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Stationary Crossflow Vortices on a Swept Wing written by R. H. Radeztsky and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theoretical and Computational Aerodynamics written by Tapan K. Sengupta and published by John Wiley & Sons. This book was released on 2014-11-17 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerodynamics has seen many developments due to the growth of scientific computing, which has caused the design cycle time of aerospace vehicles to be heavily reduced. Today computational aerodynamics appears in the preliminary step of a new design, relegating costly, time-consuming wind tunnel testing to the final stages of design. Theoretical and Computational Aerodynamics is aimed to be a comprehensive textbook, covering classical aerodynamic theories and recent applications made possible by computational aerodynamics. It starts with a discussion on lift and drag from an overall dynamical approach, and after stating the governing Navier-Stokes equation, covers potential flows and panel method. Low aspect ratio and delta wings (including vortex breakdown) are also discussed in detail, and after introducing boundary layer theory, computational aerodynamics is covered for DNS and LES. Other topics covered are on flow transition to analyse NLF airfoils, bypass transition, streamwise and cross-flow instability over swept wings, viscous transonic flow over airfoils, low Reynolds number aerodynamics, high lift devices and flow control. Key features: Blends classical theories of incompressible aerodynamics to panel methods Covers lifting surface theories and low aspect ratio wing and wing-body aerodynamics Presents computational aerodynamics from first principles for incompressible and compressible flows Covers unsteady and low Reynolds number aerodynamics Includes an up-to-date account of DNS of airfoil aerodynamics including flow transition for NLF airfoils Contains chapter problems and illustrative examples Accompanied by a website hosting problems and a solution manual Theoretical and Computational Aerodynamics is an ideal textbook for undergraduate and graduate students, and is also aimed to be a useful resource book on aerodynamics for researchers and practitioners in the research labs and the industry.
Download or read book Computation of a Delta wing Roll and hold Maneuver written by Raymond E. Gordnier and published by . This book was released on 1993 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents computations of the flowfield around an 80 degree sweep delta wing undergoing a constant roll-rate maneuver from 0 to 45 degrees. The governing equations for the problem are the unsteady, three- dimensional Navier-Stokes equations. The equations are solved using the implicit, approximately-factored algorithm of Beam-Warming. Fixed roll angle results are also presented and compared with experimental measurements to demonstrate the ability of the numerical technique to accurately capture the flowfield around a rolled delta wing. The dynamic behaviors of the vortex position and strength, as well as their corresponding effect on surface pressure, lift and roll moment, are described. A simple, quasi-static explanation of these vortex behaviors based on effective angle-of-attack and sideslip angle is proposed ... Delta wing roll, Vortex dynamics, Vortical flow, Unsteady maneuver.
Download or read book Types of Flow on Swept Wings with Special Reference to Free Boundaries and Vortex Sheets written by Dietrich Kuchemann and published by . This book was released on 1953 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vortex flow and vortex breakdown above a delta wing in high supersonic flow written by Sharon Rose Donohoe and published by . This book was released on 1996 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vortex Breakdown Over Unsteady Wings and Its Control written by and published by . This book was released on 1995 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: Control of vortex breakdown continues to be of vital importance because the breakdown may have a considerable effect on aircraft performance, such as the effect on the time-averaged lift force (Lee and Ho, 1990). Breakdown is also important because of the unsteady nature of flow downstream of vortex breakdown. The unsteadiness may affect the stability of the aircraft and also cause buffeting. The objectives of this work are to understand the physics of unsteady flow phenomena in vortex breakdown region, and to develop techniques for active (feedback) and passive (open loop) control of vortex breakdown over steady and unsteady delta wings.
Download or read book Flow Control Techniques and Applications written by Jinjun Wang and published by Cambridge University Press. This book was released on 2019 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: Master the theory, applications and control mechanisms of flow control techniques.
Download or read book Wind Tunnel Investigation of the Interaction and Breakdown Characteristics of Slender wing Vortices at Subsonic Transonic and Supersonic Speeds written by Gary E. Erickson and published by . This book was released on 1991 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Separated and Vortical Flow in Aircraft Wing Aerodynamics written by Ernst Heinrich Hirschel and published by Springer Nature. This book was released on 2020-10-04 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid mechanical aspects of separated and vortical flow in aircraft wing aerodynamics are treated. The focus is on two wing classes: (1) large aspect-ratio wings and (2) small aspect-ratio delta-type wings. Aerodynamic design issues in general are not dealt with. Discrete numerical simulation methods play a progressively larger role in aircraft design and development. Accordingly, in the introduction to the book the different mathematical models are considered, which underlie the aerodynamic computation methods (panel methods, RANS and scale-resolving methods). Special methods are the Euler methods, which as rather inexpensive methods embrace compressibility effects and also permit to describe lifting-wing flow. The concept of the kinematically active and inactive vorticity content of shear layers gives insight into many flow phenomena, but also, with the second break of symmetry---the first one is due to the Kutta condition---an explanation of lifting-wing flow fields. The prerequisite is an extended definition of separation: “flow-off separation” at sharp trailing edges of class (1) wings and at sharp leading edges of class (2) wings. The vorticity-content concept, with a compatibility condition for flow-off separation at sharp edges, permits to understand the properties of the evolving trailing vortex layer and the resulting pair of trailing vortices of class (1) wings. The concept also shows that Euler methods at sharp delta or strake leading edges of class (2) wings can give reliable results. Three main topics are treated: 1) Basic Principles are considered first: boundary-layer flow, vortex theory, the vorticity content of shear layers, Euler solutions for lifting wings, the Kutta condition in reality and the topology of skin-friction and velocity fields. 2) Unit Problems treat isolated flow phenomena of the two wing classes. Capabilities of panel and Euler methods are investigated. One Unit Problem is the flow past the wing of the NASA Common Research Model. Other Unit Problems concern the lee-side vortex system appearing at the Vortex-Flow Experiment 1 and 2 sharp- and blunt-edged delta configurations, at a delta wing with partly round leading edges, and also at the Blunt Delta Wing at hypersonic speed. 3) Selected Flow Problems of the two wing classes. In short sections practical design problems are discussed. The treatment of flow past fuselages, although desirable, was not possible in the frame of this book.
Download or read book Advanced Imaging Techniques for Flows Past Swept Wings written by and published by . This book was released on 1996 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: A major goal of this investigation is to develop a high-speed laser scanning technique for characterizing the instantaneous topology and vorticity distributions over crossflow planes of a delta wing undergoing defined rolling motion at a given angle of attack. By using new types of image construction techniques, it will be possible to determine the central physics of the three-dimensional flow structure in both the early stages of vortex breakdown, as well as in fully-stalled regions along the wing. In turn, these observations provide a basis for physically interpreting the unsteady loading on the wing. Central to this interpretation are topological representations of the streamline patterns, which provide a quantitative framework for classifying the flow patterns.
Download or read book Aerodynamics written by Theodore Von Kármán and published by Courier Corporation. This book was released on 2004-01-01 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Charming, reader-friendly chronicle by a famous pioneer in aerodynamic research traces the development of dynamic flight from the time of Newton through the 20th century. It recounts struggles of engineers and physicists with problems associated with lift, drag, stability, aeroelasticity, and the sound barrier. 72 figures. 1957 edition.
Download or read book A Water Tunnel Study of Vortex Breakdown Over Wings with Highly Swept Leading Edges written by D. H. Thompson and published by . This book was released on 1975 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
