Download or read book Analytical Model of Supersonic Turbulent Near Wake Flows written by C. E. Peters and published by . This book was released on 1976 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical model for planar and axisymmetric, supersonic, turbulent, near-wake flows is presented. The viscous region behind the blunt base is described by the integral form of the boundary-layer equations, and the inviscid outer-flow region, including the remnant of the initial turbulent boundary layer, is computed with the rotational method of characteristics. The solution of the two regions is fully coupled. The saddle-point singularity, similar to the Crocco-Lees critical point, occurs downstream of the rear stagnation point. The base pressure is obtained by iteration of the initial conditions until the flow-field solution will pass through the singularity. Base bleed of a gas different from the outer-stream gas is included in the formulation, and provision is made to treat equilibrium chemical reactions in the viscous wake. However, an unresolved problem has been encountered in the solution of the species conservation equations. Therefore, results for only single gas flows are presented. The analytical model is shown to adequately predict the effect of free-stream Mach number and initial boundary layer on the planar base pressure. In addition, the planar flow-field structure is well predicted. Axisymmetric base pressure and flow-field structure are reasonably well predicted for free-stream Mach numbers greater than 2.0, but the turbulent transport model used yields only fair results for Mach numbers less than 1.7. The effect of base bleed on the axisymmetric base pressure is well predicted. (Author).
Download or read book Analytical Nodel of Supersonic Turbulent Near wake Flows written by C. E. Peters and published by . This book was released on 1976 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical model for planar and axisymmetric, supersonic, turbulent, near-wake flows is presented. The viscous region behind the blunt base is described by the integral form of the boundary-layer equations, and the inviscid outer-flow region, including the remnant of the initial turbulent boundary layer, is computed with the rotational method of characteristics. The solution of the two regions is fully coupled. The saddle-point singularity, similar to the Crocco-Lees critical point, occurs downstream of the rear stagnation point. The base pressure is obtained by iteration of the initial conditions until the flow-field solution will pass through the singularity. Base bleed of a gas different from the outer-stream gas is included in the formulation, and provision is made to treat equilibrium chemical reactions in the viscous wake. However, an unresolved problem has been encountered in the solution of the species conservation equations. Therefore, results for only single gas flows are presented. The analytical model is shown to adequately predict the effect of free-stream Mach number and initial boundary layer on the planar base pressure. In addition, the planar flow-field structure is well predicted. Axisymmetric base pressure and flow-field structure are reasonably well predicted for free-stream Mach numbers greater than 2.0, but the turbulent transport model used yields only fair results for Mach numbers less than 1.7. The effect of base bleed on the axisymmetric base pressure is well predicted. (Author).
Download or read book Development and comparison of several analytical models for the planar turbulent near wake in supersonic flow combining component and critical point methods written by Jimmie Hugh Smith and published by . This book was released on 1973 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analytical Nodel of Supersonic Turbulent Near wake Flows written by C. E. Peters and published by . This book was released on 1976 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical model for planar and axisymmetric, supersonic, turbulent, near-wake flows is presented. The viscous region behind the blunt base is described by the integral form of the boundary-layer equations, and the inviscid outer-flow region, including the remnant of the initial turbulent boundary layer, is computed with the rotational method of characteristics. The solution of the two regions is fully coupled. The saddle-point singularity, similar to the Crocco-Lees critical point, occurs downstream of the rear stagnation point. The base pressure is obtained by iteration of the initial conditions until the flow-field solution will pass through the singularity. Base bleed of a gas different from the outer-stream gas is included in the formulation, and provision is made to treat equilibrium chemical reactions in the viscous wake. However, an unresolved problem has been encountered in the solution of the species conservation equations. Therefore, results for only single gas flows are presented. The analytical model is shown to adequately predict the effect of free-stream Mach number and initial boundary layer on the planar base pressure. In addition, the planar flow-field structure is well predicted. Axisymmetric base pressure and flow-field structure are reasonably well predicted for free-stream Mach numbers greater than 2.0, but the turbulent transport model used yields only fair results for Mach numbers less than 1.7. The effect of base bleed on the axisymmetric base pressure is well predicted. (Author).
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of the Near Wake Pressure in Supersonic Flow Using the Momentum Integral Method written by Josef Rom and published by . This book was released on 1964 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The pressure of two-dimensional base type separated regions is evaluated by use of semi-empirical analysis. The analysis is based on the momentum integral method. Empirical parameters required in the analysis are evaluated from various available experimental data. Good correlation over a large range of variation of the physical parameters is obtained in the cases of two-dimensional supersonic flows for both laminar and turbulent separation over backward facing steps and blunt bases. The axially symmetric base type flows seem to be affected by the inviscid axially symmetric external flow in a different manner than found in the two dimensional case. It seems that the parameters applicable for the two-dimensional base type flows are not sufficient for the correlation of the axially symmetric separated flows. (Author).
Download or read book A Generalized Base flow Analysis with Initial Boundary layer and Chemistry Effects written by John H. Fox and published by . This book was released on 1979 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Analysis of Supersonic Flows with Low Reynolds Number Compressible Two equation Turbulence Models Using LU Finite Volume Implicit Numerical Techniques written by and published by . This book was released on 1994 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1980 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulent Shear Layers in Supersonic Flow written by Alexander J. Smits and published by Springer Science & Business Media. This book was released on 2006-05-11 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: A good understanding of turbulent compressible flows is essential to the design and operation of high-speed vehicles. Such flows occur, for example, in the external flow over the surfaces of supersonic aircraft, and in the internal flow through the engines. Our ability to predict the aerodynamic lift, drag, propulsion and maneuverability of high-speed vehicles is crucially dependent on our knowledge of turbulent shear layers, and our understanding of their behavior in the presence of shock waves and regions of changing pressure. Turbulent Shear Layers in Supersonic Flow provides a comprehensive introduction to the field, and helps provide a basis for future work in this area. Wherever possible we use the available experimental work, and the results from numerical simulations to illustrate and develop a physical understanding of turbulent compressible flows.
Download or read book Wake Analysis for Supersonic Decelerator Applications written by Richard A. Lau and published by . This book was released on 1970 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: This investigation uses two methods for predicting the compressible wake characteristics behind two-dimensional and axisymmetric bodies in a supersonic free stream, the first involving use of shallow-water tow-channel data and mathematic relationships existing between water with a free surface and a two-dimensional, compressible gas, and the second which uses a momentum integral solution for the viscous wake and a mass flow balance across the bow shock for the inviscid wake. As part of this investigation, the theoretical solution for the two-dimensional wake was developed and the results were combined with available axisymmetric wake results into a general set of unified equations.
Download or read book Technical Abstract Bulletin written by and published by . This book was released on with total page 912 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Near Wake Flow Studies in Supersonic Flow written by Josef Rom and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The theoretical and experimental investigations carried out on supersonic flow over two-dimensional and axially symmetric base type separated flows are summarized in this report. Correlating equations for base pressure and backward facing step pressure with laminar and turbulent separation are presented. These relations are obtained from considerations of the analysis based on the integral method and experimental data. Measurements of total pressure and temperature profiles in the near wake of a two-dimensional wedge- flat plate model at M=3.5 indicate high recovery temperatures at the outer regions of the wake beyond the neck position. The development of the shock tunnel and its associated equipment is reported, including an improved method for thin film resistance thermometers calibration.
Download or read book Inhibition of Flow Separation at High Speed written by Larry L. Lynes and published by . This book was released on 1969 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The method of integral relations was successfully applied to compressible nonadiabatic turbulent boundary layers on a flat plate. The theory is designed to accept any desired eddy-viscosity model. A particular eddy-viscosity model was incorporated into the method, and the equations were programmed for application to a flat plate with no pressure gradient. The variations of the skin-friction coefficient with Reynolds number, Mach number, and temperature ratio were calculated using this program, and the results are in good accord with similar results calculated by the Spalding-Chi method and the Rubesin T' method. An analysis was made to predict to what extent turbulent separation of the free-interaction type can be inhibited by means of surface cooling. It was observed experimentally that free-interaction is applicable to separated turbulent boundary layers up to the separation point or beyond. The free-interaction model used in the analysis is based on adding the boundary-layer displacement thickness to the actual body dimensions in calculating the induced pressures. The critical temperature ratios calculated on this basis are generally greater than adiabatic wall temperature except in the supersonic range up to a Mach number approaching 3, where moderate cooling is required to inhibit separation.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt: NSA is a comprehensive collection of international nuclear science and technology literature for the period 1948 through 1976, pre-dating the prestigious INIS database, which began in 1970. NSA existed as a printed product (Volumes 1-33) initially, created by DOE's predecessor, the U.S. Atomic Energy Commission (AEC). NSA includes citations to scientific and technical reports from the AEC, the U.S. Energy Research and Development Administration and its contractors, plus other agencies and international organizations, universities, and industrial and research organizations. References to books, conference proceedings, papers, patents, dissertations, engineering drawings, and journal articles from worldwide sources are also included. Abstracts and full text are provided if available.
Download or read book Numerical Computations of Supersonic Base Flow with Special Emphasis on Turbulence Modeling written by and published by . This book was released on 1994 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A zonal, implicit, time-marching Navier-Stokes computational technique has been used to compute the turbulent supersonic base flow over cylindrical afterbodies. A critical element of calculating such flows is the turbulence model. Various eddy viscosity turbulence models have been used in the base region flow computations. These models include two algebraic turbulence models and a two-equation k-epsilon model. The k-epsilon equations are developed in a general coordinate system and solved using an implicit algorithm. Calculations with the k-epsilon model are extended up to the wall. Flow field computations have been performed for a cylindrical afterbody at M = 2.46 and at angle of attack alpha = 0. The results are compared to the experimental data for the same conditions and the same configuration. Details of the mean flow field as well as the turbulence quantifies have been presented. In addition, the computed base pressure distribution has been compared with the experiment. In general, the k-epsilon turbulence model performs better in the near wake than the algebraic models and predicts the base pressure much better. Base flow, Base pressure, Turbulence models, Wake, Supersonic flow.
Download or read book Bibliography on Aerodynamics of Airframe engine Integration of High speed Turbine powered Aircraft Volume 1 written by and published by . This book was released on 1980 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
