Download or read book An Investigation of the Fundamental Cause of Asymmetric Separated Flow written by and published by . This book was released on 1992 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cause of the phenomenon of steady asymmetric flow on cones at moderately high angles of attack is the subject of this investigation. At very higher angles of attack, the flow will become unsteady with a Karman vortex street being shed downstream. This second phenomenon was not considered in the current research project. The investigation used computational fluid dynamics as a tool to uncover the fundamental cause of asymmetric separated flows. The appearance of new flow features as the critical angle of attack was approached was studied in detail. Isolating asymmetric disturbances to specific portions of the flow was also attempted. The stability of the symmetric flow above the critical angle of attack was investigated analytically. The transition of the flow from symmetric to asymmetric as the computation was continued was studied in detail. All of these studies indicated that the interaction of the vortices in the cross flow plane results in an instability in the symmetric flow. In addition, the interaction between the vortices seems to be somewhat global in nature.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research in Progress written by and published by . This book was released on 1991 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA SP written by and published by . This book was released on 1993 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Fluid Dynamics Techniques written by Fathi Habashi and published by CRC Press. This book was released on 1995-11-22 with total page 930 pages. Available in PDF, EPUB and Kindle. Book excerpt: First published in 1995. Routledge is an imprint of Taylor & Francis, an informa company.
Download or read book Aeronautical Engineering written by and published by . This book was released on 1971 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA)
Download or read book Experimental Investigation of a Three dimensional Separated Diffuser written by Babajide Oluyemi Kolade and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Boundary layer separation is important in many engineering applications. Flows in aerodynamic devices such as diffusers, aircraft engines' compressors, and airfoils face significant adverse pressure gradients and as such are at risk of separating. Boundary layer separation creates a separation bubble between the primary flow and the bounding surface. The bubble is highly unsteady and the interaction with the primary flow may cause sub-optimal performance or even catastrophic loss of functionality. This work investigates critical aspects of practical separated flows. The test case is an asymmetric three-dimensional stalled diffuser, with unambiguously specified boundary conditions, that is fed by a fully-developed low-aspect ratio rectangular duct. Particle Image Velocimetry (PIV) is used to measure mean flow, turbulence, and higher-order statistics in the diffuser for multiple Reynolds numbers and spanwise planes, and at high spatial resolution and with low uncertainty. The mean flow development, Reynolds stress development, and turbulence scaling in the reverse flow region and in the separated shear layer are investigated. The turbulence structure and integral length scales are examined using two-point correlations and structure parameters. Additionally, the effect of three-dimensionality and the Reynolds number effect on the mean flow and turbulence are discussed. The boundary layer separates off the smoothly contoured bottom diverging wall of the diffuser due to the strong adverse pressure gradient in the streamwise direction. The lower-momentum corner regions at the junctions of the diffuser walls experiences additional spanwise adverse pressure gradient. At the diffuser throat, flow in the corner regions is affected by vestiges of the secondary flow in the inlet duct. Hence, the flow in corner regions experiences more significant flow reversal and the separation points in these planes are upstream of the separation points of the interior planes. This results in a reverse flow region that is three-dimensional. Additionally, the PDFs of the streamwise velocities at the separation and reattachment points on the bottom wall are positively skewed, indicating that the events resulting in forward motion at these locations are more energetic and less frequent than the events resulting in backward motion. Reynolds number has only a mild effect on the mean flow. High levels of the Reynolds stresses develop in the separated shear layer due to the adverse pressure gradient, as an inflection point is generated in the mean velocity profile and then displaced away from the wall as the boundary layer separates. The additional strain rate components and the secondary flow in the inlet duct modify the characteristics of the Reynolds stresses in the corner regions of the diffuser. There is no sharp change in the Reynolds stress behavior across the separation line because there are significant levels of turbulent transport of kinetic energy into the reverse flow region. Two-point correlation profiles show that the largest eddies in the separated shear layer penetrate deep into the reverse flow region and that the integral length scales peak just before reattachment. The turbulence in this flow is energetic, locally isotropic in some portion of the flow, strongly inhomogeneous, and is a strong function of Reynolds number. The experiment described here and the experimental data provided in this thesis will serve well as a benchmark test case for validating CFD models.
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1984 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Miscellaneous Report Coastal Engineering Research Center written by Coastal Engineering Research Center (U.S.) and published by . This book was released on 1976 with total page 754 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Symposium Transsonicum III written by Jürgen Zierep and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 503 pages. Available in PDF, EPUB and Kindle. Book excerpt: Continuing the tradition of the IUTAM Symposia TRANSSONICA, this review of the numerical simulation and physical modelling of transonic flows presents new developments in the fields of computational and experimental aerodynamics. A major topic of the symposium proceedings is the evaluation of present numerical analysis techniques with respect to transonic aerodynamics. In the field of experimental aerodynamics, the high Reynolds number effect and the interference-free testing in transonic wind tunnels are of special interest.
Download or read book NASA Technical Paper written by and published by . This book was released on 1981 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Understanding the Causes of Asymmetries in Earth s Magnetosphere Ionosphere System written by Denny Oliveira and published by Frontiers Media SA. This book was released on 2023-04-25 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Static Performance of a Fixed Geometry Exhaust Nozzle Incorporating Porous Cavities for Shock Boundary Layer Interaction Control written by Scott C. Asbury and published by . This book was released on 1999 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wind Tunnel Investigation of the Aerodynamic Hysteresis Phenomenon on the F 4 Aircraft and Its Effects on Aircraft Motion written by J. F. Herman and published by . This book was released on 1980 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wind tunnel test program and an analytical study were conducted to investigate aerodynamic hysteresis phenomena on the F-4 aircraft. The wind tunnel test was conducted in the Arnold Engineering Development Center (AEDC) Aerodynamic Wind Tunnel (4T) to investigate the source of aerodynamic hysteresis in static aerodynamic data. The wind tunnel test also provided data that were used in a motion simulation study of the effect of hysteresis on predicted aircraft motion. Static longitudinal lateral directional force and moment data and wing pressure data were obtained on a 0.5-scale model (without pylons or external stores) with various simulated leading-edge slats. These data include the effects of Mach number, angle of attack, model movement, and time dependence on the aerodynamic hysteresis characteristics. Data are presented for the Mach number range from 0.7 to 0.95 at angles of attack from -4 to 24 deg at zero deg sideslip angle and for sideslipe angles from -12 to 12 deg at angles of attack of 5, 10, 15, and 20 deg. Six-degrees-of-freedom motion simulation studies were used to assess the effect of hysteresis in the rolling-moment coefficient on the prediction of aircraft motion. Simulations of various flight maneuvers were conducted both with and without hysteresis in the aerodynamic data. (Author).
Download or read book Recent Asian Research on Thermal and Fluid Sciences written by Abhilash Suryan and published by Springer Nature. This book was released on 2020-02-18 with total page 693 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a collection of the best papers from the Seventh Asian Joint Workshop on Thermophysics and Fluid Science (AJWTF7 2018), which was held in Trivandrum, India, in November 2018. The papers highlight research outputs from India, China, Japan, Korea and Bangladesh, and many of them report on collaborative efforts by researchers from these countries. The topics covered include Aero-Acoustics, Aerodynamics, Aerospace Engineering, Bio-Fluidics, Combustion, Flow Measurement, Control and Instrumentation, Fluid Dynamics, Heat and Mass Transfer, Thermodynamics, Mixing and Chemically Reacting Flows, Multiphase Flows, Micro/Nano Flows, Noise/NOx/SOx Reduction, Propulsion, Transonic and Supersonic Flows, and Turbomachinery. The book is one of the first on the topic to gather contributions from some of the leading countries in Asia. Given its scope, it will benefit researchers and students working on research problems in the thermal and fluid sciences.
Download or read book 30th International Symposium on Shock Waves 1 written by Gabi Ben-Dor and published by Springer. This book was released on 2017-08-09 with total page 746 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings collect the papers presented at the 30th International Symposium on Shock Waves (ISSW30), which was held in Tel-Aviv Israel from July 19 to July 24, 2015. The Symposium was organized by Ortra Ltd. The ISSW30 focused on the state of knowledge of the following areas: Nozzle Flow, Supersonic and Hypersonic Flows with Shocks, Supersonic Jets, Chemical Kinetics, Chemical Reacting Flows, Detonation, Combustion, Ignition, Shock Wave Reflection and Interaction, Shock Wave Interaction with Obstacles, Shock Wave Interaction with Porous Media, Shock Wave Interaction with Granular Media, Shock Wave Interaction with Dusty Media, Plasma, Magnetohyrdrodynamics, Re-entry to Earth Atmosphere, Shock Waves in Rarefied Gases, Shock Waves in Condensed Matter (Solids and Liquids), Shock Waves in Dense Gases, Shock Wave Focusing, Richtmyer-Meshkov Instability, Shock Boundary Layer Interaction, Multiphase Flow, Blast Waves, Facilities, Flow Visualization, and Numerical Methods. The two volumes serve as a reference for the participants of the ISSW30 and anyone interested in these fields.
Download or read book Transonic Symposium Theory Application and Experiment written by and published by . This book was released on 1989 with total page 964 pages. Available in PDF, EPUB and Kindle. Book excerpt:
