Download or read book Calculation of Three dimensional Boundary Layers on Bodies at Incidence written by V. C. Patel and published by . This book was released on 1982 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-dimensional thin boundary-layer equations for laminar and turbulent flows are solved by two different numerical schemes. The methods are applied to the flow over bodies of revolution at incidence and the results are compared with the available experimental data in order to study the range of validity of the classical boundary-layer approximations in regions of increasing circumferential gradients and flow reversal associated with the early stages of a free-vortex type of separation. Comparison with the DFVLR 6:1 spheroid data of Meier et al and the 4:1 combination-body data of Ramaprian, Patel and Choi indicate that the methods perform well in regions where the boundary layer remains thin but the predictions deteriorate as the boundary layer thickens. The results point out the need for the development of methods of handle thick boundary layers and viscous-inviscid interactions. (Author).
Download or read book Calculation of Three Dimensional Boundary Layers on Bodies of Revolution at Incidence written by Tuncer Cebeci and published by . This book was released on 1978 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: The laminar three-dimensional boundary layer on a body of revolution at incidence is investigated using two methods. In the first, the standard equations are solved numerically using the Keller box scheme. The second method solves a set of equations, which contain the standard equations, derived from the assumption that crossflow gradients may be important. Since these equations are elliptic in the crossflow plane, an ADI procedure is used for their solution. In regions where there is no crossflow reversal, both methods yield the same results. However, differences appear in regions where the crossflow is not unidirectional. Reasons for this discrepancy are discussed and the relative merits of each procedure identified. (Author).
Download or read book Three Dimensional Boundary Layers on Bodies of Revolution at Incidence written by V. C. Patel and published by . This book was released on 1978 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes the objectives and accomplishments of an experimental and theoretical investigation of the boundary layer development on bodies of revolution at incidence. The results of the flow visualization studies in laminar flow, detailed measurements in a turbulent boundary layer, and calculations of laminar as well as turbulent boundary layers using two different numerical schemes and turbulence models are reviewed to emphasize the important characteristics of separation in three dimensions.
Download or read book Three Dimensional Laminar Boundary Layer Over Body of Revolution at Incidence Part VI General Methods and Results of the Case of High Incidence written by K. C. Wang and published by . This book was released on 1973 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents general methods for calculating three-dimensional laminar boundary layers over inclined blunt bodies (not necessarily bodies of revolution). Complete incompressible results for a prolate spheroid at 30 degrees incidence are presented, and the computational procedures are described. The rule of the zone of dependence was observed. The results display for the first time the boundary layer structure over a non-spherical and non-conical blunt body in all details, and confirm the open-type of separation proposed earlier. (Author).
Download or read book Three Dimensional Laminar Boundary Layer Over Body of Revolution at Incidence Part IX Difference Method and Documentation of Program BLIND3 written by K. C. Wang and published by . This book was released on 1975 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report documents the program 'BLIND3' and its associated difference methods. BLIND3 stands for Boundary Layer in 3 Dimensions. This program is for calculating genuine three-dimensional, incompressible, laminar boundary layer over a blunt-body at incidence. The whole calculation consists of the following five parts: inviscid calculations from known inviscid solution, stagnation-point boundary layer, symmetry-plane boundary layer, nose region boundary layer, and main body boundary layer. This program has been written in FORTRAN 5 language, and used for a UNIVAC 1108 computer in batch mode and under Exec. 8 system. It has been employed to obtain complete boundary layer solutions for a prolate spheroid at low and high incidences.
Download or read book Computational Implications of the Zone of Dependence Concept for Three dimensional Boundary Layers on a Spinning Body written by Clarence W. Kitchens (Jr.) and published by . This book was released on 1975 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: The properties of the three-dimensional boundary-layer equations and the influence of these properties on numerical solutions are examined. The three-dimensional boundary-layer equations are parabolic, but they possess a secondary hyperbolic-like, property. This hyperbolic property leads to the zone of dependence concept. It is shown that the zone of dependence concept plays an important role in obtaining accurate numerical solutions for three-dimensional boundary-layer problems; it is especially important for calculating the boundary layer on a spinning body at incidence. A simple flow field which simulates the essential features of this problem and is an exact solution of the three-dimensional boundary-layer equations is constructed.
Download or read book The Three dimensional Boundary Layer written by Naval Ordnance Test Station (Inyokern, Calif.) and published by . This book was released on 1951 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computation of Three Dimensional Complex Flows written by Michel Deville and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: Der Sammelband enthält Beiträge einer Tagung über die Simulation von dreidimensionalen Flüssigkeiten. Sie geben einen Überblick über den Stand des Wissens auf dem Gebiet der numerischen Simulation der Turbulenz, angewandt auf eine weite Spanne von Problemen wie Aerodynamik, Nicht-Newtonsche Flüssigkeiten, Konvektion.This volume contains the material presented at the IMACS-COST Conference on CFD, Three-Dimensional Complex Flows, held in Lausanne (Switzerland), September 13 - 15, 1995. It gives an overview of the current state of numerical simulation and turbulence modelling applied to a wide range of fluid flow problems such as an example aerodynamics, non-Newtonian flows, transition, thermal convection.
Download or read book Calculation of the Boundary layer Flow in the Windward Symmetry Plane of a Spherically Blunted Axisymmetric Body at Angle of Attack Including Streamline swallowing Effects written by Arloe W. Mayne (Jr.) and published by . This book was released on 1973 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-dimensional compressible boundary-layer equations are particularized to the windward symmetry plane of a spherically blunted axisymmetric body at incidence under hypersonic conditions. Through the use eddy transport and streamwise intermittency both transitional and fully turbulent boundary layers may be treated. A scheme is presented for determining the outer-edge boundary conditions based on a mass flow balance treatment of the boundary-layer entrainment of the inviscid flow. A finite-difference technique is described for solving the set of partial differential equation governing the boundary-layer flow, and for treating the streamline-swallowing phenomenon.
Download or read book The Role of the Zone of Dependence Concept in Three dimensional Boundary layer Calculations written by Clarence W. Kitchens (Jr.) and published by . This book was released on 1975 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: The subject is studied for the general initial-value problem which arises in several applications; e.g., a spinning body at incidence. An exact solution which simulates the essential features of the boundary layer on such a body is used as a test case. The zone of dependence concept places a restriction on the local mesh aspect ratio that may be used. Results from four finite-difference schemes are compared against the exact solution for various wall speeds and mesh aspect ratios. Error growth occurs when the zone of dependence rule is not satisfied. The sensitivity and manner of error growth for the four schemes are different; two of them are relatively insensitive. From stability analyses it is shown that the concepts of stability and zone of dependence are not the same. Our numerical experiments partly contradict the stability analyses.
Download or read book Similar Three dimensional Boundary Layers written by Theo Geis and published by . This book was released on 1961 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Three dimensional Boundary Layers on Bodies of Revolution at Incidence written by Do-Hyung Choi and published by . This book was released on 1978 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Calculation of Boundary Layers and Separation on a Spheroid at Incidence written by V. C. Patel and published by . This book was released on 1982 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-dimensional boundary layers on a 6:1 spheroid at an incidence of 10 degrees have been calculated at two Reynolds numbers and comparisons have been made with the corresponding data of Meier et al. The results clearly demonstrate the capabilities and limitations of first-order boundary-layer theory. At the lower Reynolds number, the laminar boundary-layer calculations are in good agreement with the data on the the windward side of the body and separation is predicted in the region where the experiments indicated near zero wall shear stress just before transition to turbulent flow. The solutions have been interpreted in the light of previous proposals concerning the topology of three-dimensional flow separation. Although the results support several alternative possibilities, it is concluded that boundary-layer calculations, by themselves, are insufficient to identify a clear choice.
Download or read book Studies of Three Dimensional Boundary Layers on Bodies of Revolution III Cones at Incidence in Supersonic Flow written by Tuncer Cebeci and published by . This book was released on 1982 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation is carried out into the properties of a nonsimiliar boundary layer on a cone at incidence with special reference to the flow near the leeside line of symmetry. The nonsimilarity is induced by allowing suction near the vertex of the cone and the external velocity is given by supersonic inviscid theory. The principal new results of the theory may be expressed in terms of a parameter -k, which is approximately equivalent to the angle of attack of the cone. Three ranges of k have been identified. For small negative values of k, the three-dimensional boundary layer on the cone is smooth everywhere and, once the suction is removed, rapidly approaches a semi-similarity form as the distance from the vertex increases. For more negative values of k the boundary layer is not smooth near the leeside of the cone but can be computed everywhere. The nature of this singularity is partially explained in terms of a collision phenomenon. If k decreases further, separation occurs in computations from the windward side of the cone. The solution develops a singularity along this line provided sufficient care is taken in the calculations. An apparent nonuniqueness in the solution prevents integration from the leeside over the remainder of the region of accessibility.
Download or read book Studies on Three Dimensional Boundary Layers on Bodies of Revolution II Three Dimensional Laminar Boundary Layers and the OK of Accessibility written by Tuncer Cebeci and published by . This book was released on 1980 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation is carried out into the structure of the laminar boundary layer originating from the forward stagnation point of a prolate spheroid at incidence in a uniform stream, assuming that the external velocity distribution is given by attached potential theory. The principal new results of the study are: (1) A new transformation of the body coordinates is devised which facilitates the computation of the solution near the nose, (2) Two variations of the standard box method of solving the equations are devised to enable solutions to be computed in regions of cross-flow reversal, (3) Whereas in two dimensional flows the effect of the boundary layer approaching separation on the external flow may be represented by a blowing velocity, in the present study we find that this is only true near the windward line of symmetry, (4) The boundary layer over the whole of the spheroid cannot be computed in an integration from the forward stagnation point. (5) For alpha> or = 15 deg the accessible region on the leeward side of the ok is largely determined by the external streamline through the ok.
Download or read book Flow visualization of Three dimensional Boundary layer Separation on Bodies of Revolution at Incidence written by Taeyoung Han and published by . This book was released on 1977 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface streamline patterns on three bodies of revolution, namely a spheroid, a low-drag body and a hemisphere-hemispheroid combination body, have been examined at several angles of attack. Most of the tests were performed at low Reynolds numbers in a hydraulic flume using colored dye to make the surface flow visible. A limited number of experiments was also carried out in a wind tunnel, using wool tufts, to study the influence of Reynolds number and turbulent separation. The study has verified some of the important qualitative features of three-dimensional separation criteria proposed earlier by Maskell, Lighthill, Wang and others. The observed locations of laminar separation lines on a spheroid at various incidences have been compared with the numerical boundary-layer solutions of Wang, and it is suggested that the quantitative differences may be attributed to the significant viscous-inviscid interaction, especially at large incidences. (Author).
Download or read book Three Dimensional Turbulent Boundary Layer on a Body of Revolution at Incidence written by V. C. Patel and published by . This book was released on 1983 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental and theoretical study of three-dimensional boundary layers on bodies of revolution at incidence was conducted during the period May 1980-July 1983. This final report summarizes the technical accomplishments. Reference is made to previous reports and papers resulting from the study and some recent experimental results on the boundary layer in the plane of symmetry and the vortex formation region are presented. One of the primary objectives of this study was to develop instrumentation for the measurement of the mean flow and the Reynolds stresses in three-dimensional turbulent boundary layers, and to use these to supplement the mean-flow measurements made earlier by Ramaprian, Patel and Choi on the combination body at an incidence of 15 degrees.
