Download or read book Characteristics of Three dimensional Turbulent Jets written by Choudary Rama Krishna Bobba and published by . This book was released on 1979 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book CHARACTERISTICS OF THREE DIMENSIONAL TURBULENT JETS A NUMERICAL STUDY written by CHOUDARY R. BOBBA and published by . This book was released on 1981 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulent Jets written by N. Rajaratnam and published by Elsevier. This book was released on 1976-01-01 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent Jets

Download or read book Characteristics of 3D Turbulent Jets in Crossflow written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-10-25 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three dimensional turbulent jets in crossflow at low to medium jet-to-crossflow velocity ratios are computed with a finite volume numerical procedure which utilizes a second-moment closure model to approximate the Reynolds stresses. A multigrid method is used to accelerate the convergence rate of the procedure. Comparison of the computations to measured data show good qualitative agreement. All trends are correctly predicted, though there is some uncertainty on the height of penetration of the jet. The evolution of the vorticity field is used to explore the jet-crossflow interaction. Demuren, A. O. Glenn Research Center NASA ORDER C-99066-G...

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characteristics of 3D Turbulent Jets in Crossflow written by A. O. Demuren and published by . This book was released on 1991 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Turbulent Jets with Rectangular Cross Section written by Robert V. Wilson and published by . This book was released on 1997 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-dimensional turbulent jets with rectangular cross-section are simulated with a finite-difference numerical method. The full Navier-Stokes equations are solved at low Reynolds numbers, whereas at the high Reynolds numbers filtered forms of the equations are solved along with a subgrid scale model to approximate effects of the unresolved scales. A 2-N storage, third-order Runge-Kutta scheme is used for temporal discretization and a fourth-order compact scheme is used for spatial discretization. Computations are performed for different inlet conditions which represent different types of jet forcing. The phenomenon of axis-switching is observed, and it is confirmed that this is based on self-induction of the vorticity field. Budgets of the mean streamwise velocity show that convection is balanced by gradients of the Reynolds stresses and the pressure.

Download or read book A Computational Study of Spatially Evolving Turbulent Plane Jets written by Scott Alan Stanley and published by . This book was released on 1998 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Complex Three dimensional Turbulent Free Jets written by Robert V. Wilson and published by . This book was released on 1996 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulent Shear Flows I written by F. Durst and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present book contains papers that have been selected from contributions to the First International Symposium on Turbulent Shear Flows which was held from the 18th to 20th April 1977 at The Pennsylvania State University, University Park, Pennsylvania, USA. Attend ees from close to 20 countries presented over 100 contributions at this meeting in which many aspects of the current activities in turbulence research were covered. Five topics received particular attention at the Symposium: Free Flows Wall Flows Recirculating Flows Developments in Reynolds Stress Closures New Directions in Modeling This is also reflected in the five chapters of this book with contributions from research workers from different countries. Each chapter covers the most valuable contributions of the conference to the particular chapter topic. Of course, there were many additional good con tributions to each subject at the meeting but the limitation imposed on the length of this volume required that a selection be made. The realization of the First International Symposium on Turbulent Shear Flows was p- sible by the general support of: U. S. Army Research Office U. S. Navy Research Office Continuing Education Center of The Pennsylvania State University The conference organization was carried out by the organizing committee consisting of: F. Durst, Universitat Karlsruhe, Karlsruhe, Fed. Rep. of Germany V. W. Goldschmidt, Purdue University, West Lafayette, Ind. , USA B. E. Launder, University of California, Davis, Calif. , USA F. W. Schmidt, Pennsylvania State University, University Park, Penna.

Download or read book Computations of Complex Three Dimensional Turbulent Free Jets written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-23 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-dimensional, incompressible turbulent jets with rectangular and elliptical cross-sections are simulated with a finite-difference numerical method. The full Navier- Stokes equations are solved at low Reynolds numbers, whereas at high Reynolds numbers filtered forms of the equations are solved along with a sub-grid scale model to approximate the effects of the unresolved scales. A 2-N storage, third-order Runge-Kutta scheme is used for temporary discretization and a fourth-order compact scheme is used for spatial discretization. Although such methods are widely used in the simulation of compressible flows, the lack of an evolution equation for pressure or density presents particular difficulty in incompressible flows. The pressure-velocity coupling must be established indirectly. It is achieved, in this study, through a Poisson equation which is solved by a compact scheme of the same order of accuracy. The numerical formulation is validated and the dispersion and dissipation errors are documented by the solution of a wide range of benchmark problems. Three-dimensional computations are performed for different inlet conditions which model the naturally developing and forced jets. The experimentally observed phenomenon of axis-switching is captured in the numerical simulation, and it is confirmed through flow visualization that this is based on self-induction of the vorticity field. Statistical quantities such as mean velocity, mean pressure, two-point velocity spatial correlations and Reynolds stresses are presented. Detailed budgets of the mean momentum and Reynolds stresses are presented. Detailed budgets of the mean momentum and Reynolds stress equations are presented to aid in the turbulence modeling of complex jets. Simulations of circular jets are used to quantify the effect of the non-uniform curvature of the non-circular jets. Wilson, Robert V. and Demuren, Ayodeji O. Langley Research Center NASA-CR-203976, NAS 1.26:203976, ICAM-97-101 NCC1-232...

Download or read book Numerical Study of Three Dimensional Turbulent Flows written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct numerical and large-eddy simulations were used to perform numerical experiments' relevant to the cases of interest. We employ a plane-channel geometry and impose mean-flow perturbations by subjecung fully developed 2D Poiseuille flow to irrotational deformations andlor in-plane motion of the channel walls. The former corresponds to outer-layer strains induced in boundary layers by pressure gradients, the latter to sudden variations in the near-wall region, caused by either step changes in the surface conditions or the combination of an outer-layer change and the no-slip boundary condition. This combination allows the physics of a broad class of spatially developing wall shear layers to be duplicated with a temporally evolving channel flow. The temporal computations can be realized much more effectively than can simulations of a spatial boundary layer. providing a much more extensive study for a given cost. As a consequence. we can consider a wide variety of mean-flow perturbations. Moreover, since mean statistics for these flows satisfy a one dimensional unsteady problem that contains the essential features of the spatial flow, they provide an effident means of testing on%point dosure models.

Download or read book Investigation of Features of Flow of Three Dimensional Turbulent Wall Jets with and Without Pressure Gradient written by John R. Weske and published by . This book was released on 1968 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The characteristics of 3-dimensional wall jets are strongly influenced by secondary motion particularly in the region close to the nozzle. There is evidence suggesting that jets from narrow and tall nozzles will spread a wall jet more broadly over a wall than low and broad nozzles. Three-dimensional wall jets with pressure gradients, in the region close to the nozzle are subject to the same effects of secondary motions as are wall jets without pressure gradients, while in their later course they may acquire the characteristics of turbulent flow in ducts. Theoretical investigation of the action of Reynolds stresses serves to clarify the nature of secondary motions and to show the reason for contrasting characteristics of secondary flow in jets and in ducts as well as the fading out of secondary motion with increasing jet diffusion. (Author).

Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Numerical Study of Confined Turbulent Jets written by J. Zhu and published by . This book was released on 1993 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: A numerical investigation is reported of turbulent incompressible jets confined in two ducts, one cylindrical and the other conical with a 5 degree divergence. In each case, three Craya-Curtet numbers are considered which correspond, respectively, to flow situations with no moderate and strong recirculation. Turbulence closure is achieved by using the k-epsilon model and a recently proposed realizable Reynolds stress algebraic equation model that relates the Reynolds stresses explicitly to the quadratic terms of the mean velocity gradients and ensures the positiveness of each component of the turbulent kinetic energy. Calculations are carried out with a finite-volume procedure using boundary-fitted curvilinear coordinates. A second-order accurate, bounded convection scheme and sufficiently fine grids are used to prevent the solutions from being contaminated by numerical diffusion. The calculated results are compared extensively with the available experimental data. It is shown that the numerical methods presented are capable of capturing the essential flow features observed in the experiments and that the realizable Reynolds stress algebraic equation model performs much better than the k-epsilon model for this class of flows of great practical importance.

Download or read book Experimental and Numerical Study of Two dimensional Free and Impinging Turbulent Jets written by Michael Staiano and published by . This book was released on 1992 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Three dimensional Numerical Simulation of a Supersonic Under expanded Rectangular Jet written by Ibraheem M. A. Al-Qadi and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: A three-dimensional numerical simulation of the unsteady flow in an under-expanded supersonic rectangular jet has been conducted for the purpose of investigating and analyzing the production and propagation of jet noise. The compressible three-dimensional Navier-Stokes equations are solved using high-order spatial and temporal differencing schemes. The solution method applies linear and nonlinear filtering schemes to produce oscillation-free shocks and discontinuities while minimizing dissipation effects in smooth regions. The solution method also applies nonreflecting boundary conditions to minimize reflections. Characteristic boundary conditions are implemented at the upstream and far-field boundaries and an absorbing buffer zone is added at the outflow boundary. OpenMP shared- memory model was utilized to parallelize the simulation and good parallel performance was achieved. The code was used to conduct a time dependent numerical simulation of an under-expanded supersonic rectangular jet. A comprehensive database of the simulation was generated. The results of the simulation were validated against experimental measurements and show very good agreement. The simulation is shown to resolve critical unsteady flow features of the jet such as vortex shedding, shock-cell structure, shock shear-layer interaction, flapping, and axis-switching. Visualization of the unsteady flow and analysis of the turbulent flow-field shows that the location of axis-switching is immediately downstream of the fourth shock. It is also observed that the location of the dominant screech source is at the third shock. Two-point space-time correlations demonstrate that the convection velocities in the jet shear layer are highly modulated by the presence of shock waves. Spectral analysis show that the simulation predicts, with good accuracy, screech modes frequencies, wavelengths, phase, and amplitudes. Analysis inside the jet shear layer and in the acoustic near-field reveal exact correspondence in frequency and phase between the inner and the outer parts of the screech loop. The simulation also predicts the complex pattern of the near acoustic field associated with screech. The current simulation represents the first successful three- dimensional numerical simulation of an under-expanded supersonic rectangular jet. It also represents a significant contribution towards accurate prediction of noise production and far-field radiation in supersonic jets. The computational tools developed in this study can be used to investigate a wide range of problems related to unsteady flows and aeroacoustics.