Download or read book Computations of an Axisymmetric Turbulent Free Jet written by Shawn Douglas Givler and published by . This book was released on 1994 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Application of Some Turbulence Models to the Computation of an Axisymmetric Jet in Streaming Flow written by S. Biringen and published by . This book was released on 1974 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Calculation of the Transition Region of a Turbulent Jet written by A. S. Ginevskii and published by . This book was released on 1968 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: An approximate calculation method is developed for the transition sections of plane and axisymmetric turbulent jets in a co-moving stream. It is shown why earlier methods, based on differentiation between the initial and final sections, are not applicable in the transition (mixing) region. The velocity profiles obtained by this method in the transition region turn out to be the same for plane and axisymmetric jets, and can be used to calculate the variation of the jet parameters along the stream axis by using the set of integral equations connecting the angular momentum and the energy. Limiting parameters are defined under which the results coincide with the velocity profile of the main section of the turbulent jet. It is concluded that in first approximation the external boundary of the transition layer is straight and is a continuation of the outer boundary of the outer section. The method is then demonstrated to be suitable for a determination of continuous velocity-profile deformation in the transition region. (Author).

Download or read book Turbulent Buoyant Jets and Plumes written by Wolfgang Rodi and published by Elsevier. This book was released on 2014-05-09 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Science & Applications of Heat and Mass Transfer: Reports, Reviews, & Computer Programs, Volume 6: Turbulent Buoyant Jets and Plumes focuses on the formation, properties, characteristics, and reactions of turbulent jets and plumes. The selection first offers information on the mechanics of turbulent buoyant jets and plumes and turbulent buoyant jets in shallow fluid layers. Discussions focus on submerged buoyant jets into shallow fluid, horizontal surface or interface jets into shallow layers, fundamental considerations, and turbulent buoyant jets (forced plumes). The manuscript then examines a turbulence model for buoyant flows and its application to vertical buoyant jets, including mathematical model, calculation of vertical buoyant jets, and explanation of velocity and temperature spreading in pure jets and pure plumes. The publication is a dependable reference for scientists and readers interested in turbulent buoyant jets and plumes.

Download or read book Experimental and Theoretical Studies of Axisymmetric Free Jets written by and published by . This book was released on 1959 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Some experimental and theoretical studies have been made of axisymmetric free jets exhausting from sonic and supersonic nozzles into still air and into supersonic streams with a view toward problems associated with propulsive jets and the investigation of these problems. For jets exhausting into still air, consideration is given to the effects of jet Mach number, nozzle divergence angle, and jet static-pressure ratio upon jet structure, jet wavelength, and the shape and curvature of the jet boundary. Studies of the effects of the ratio of specific heats of the jets are included as are observations pertaining to jet noise and jet simulation. For jets exhausting into supersonic streams, an attempt has been made to present primarily theoretical curves of the type that may be useful in evaluating certain jet interference effects and in formulating experimental studies. The primary variables considered are jet Mach number, free-stream Mach number, jet static-pressure ratio, ratio of specific heats of the jet, nozzle exit angle, and boattail angle. The simulation problem and the case of a hypothetical hypersonic vehicle are examined. A few experimental observations are included.

Download or read book Computation of Turbulent Axisymmetric and Nonaxisymmetric Jet Flows Using the K e Model written by Andrew T. Thies and published by . This book was released on 1996 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Investigation of High order High resolution Methods for Axisymmetric Turbulent Jet Using ILES written by António Filipe Baranda Inok and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This Philosophiae Doctor thesis presents the motivation, objectives and reasoning behind the undertaken project. This research, study the capability of compressible Implicit Large Eddy Simulation (ILES) in predicting free shear layer flows, under different free stream regimes (Static and Co-flow jets). Unsteady flows or jet flows are non-uniform in structure, temperature, pressure and velocity. Turbulent mixing is of particular importance for the developing of this class of flows. As a shear layer is formed immediately downstream of the jet exhaust, an early linear instability involving exponential growth of small perturbations is introduced at the jet discharge. Beyond this development stage, in the non-linear Kelvin-Helmholtz instability region large scale vortex rings roll up, and their dynamics of formation and merging become the defining feature of the transitional shear flow into fully developed regime. This class of flows is particularly relevant to numerical predictions, as the extreme nature of the flow in question is considered as a benchmark; however, experimental data should be selected carefully as some results are controversial. To qualify the behaviour of unsteady flows, some important criteria have been selected for the analysis of the flow quantities at different regions of the flow field (average velocities, Reynolds stresses and dissipation rates). A good estimation of high-order statistics (Standard Deviation, Skewness and Kurtosis) correspond to mathematical steadiness and convergence of results. From the physical point of view, similarity analysis between jet's wake sections reveals physical steadiness in results. Spectral analysis of the different regions of the flow field could be used as a sign that the energy cascade is correctly predicted or efficiently enough since this is where the smallest scales are usually present and which in effect require to be modelled by the different numerical schemes. The flow solver has been reviewed and improved. The former, a revised version of the reconstruction numerical schemes (WENO 5th and WENO 9th orders) has been performed and tested, the correspondent results have been compared against analytical data; the latter, correction of the method to compute the Jacobian of the transformation (singularity correction), by changing from the standard algebraic to geometric method, and augmented with transparent boundary condition, giving mathematical and physical meaning to the obtained results. The flow solver improvements and review have been verified and validated through simulations of a compressible Convergent-Divergent Nozzle (CDN), and the standard and a modified version of the Shock tube test cases, where the results are gained with minimal modelling effort. The study of numerical errors associated with the simulations of turbulent flows, for unsteady explicit time step predictions, have been performed and a new formula proposed. Ten different computational methods have been employed in the framework of ILES and computations have been performed for a jet flow configuration for which experimental data and DNS are available. It can be seen that a numerical error bar can be defined that takes into account the errors arising from the different numerical building blocks of the simulation method. The effects of different grids, Riemann solvers and numerical reconstruction schemes have been considered, however, the approach can be extended to take into account the effects of the initial and boundary conditions as well as subgrid scale modelling, if applicable. From the physical analysis several observations were established, revealing that differences in terms of jet's core size are not an important parameter in terms of quantification and qualification of predictions, in other words, data should be reduced to the jet's inertial reference system. Moreover, the comparative study has been performed to identify the differences between Riemann solvers (CBS and HLLC), Low Mach number Limiting/ Corrections (LMC), numerical reconstruction schemes (MUSCL and WENO) and spatial order of accuracy (2nd-order LMC, 5th-order LMC and 9th-order schemes) in combination with the most efficient cost/resolution discretization level (Medium mesh). The comparisons between results reveals for the Static and Co-Flow jets that the CBS MUSCL 5th-order LMC and the HLLC MUSCL 5th-order LMC as the most accurate schemes in predicting this class of flows, accordingly. Furthermore, the selected numerical methods show to be in accordance with the empirical (Static) and experimental (Co-flow) results in terms of resonance frequency and/or Strouhal number; also, the expected behaviour in terms of spectral energy decay rate throughout the jet's central line is observed. To conclude the study of the Static jet case, a possible explanation for the jet's buoyancy effect is presented.

Download or read book The Effect of Exit Conditions on the Development of an Axisymmetric Turbulent Free Jet written by Stanely James Kleis and published by . This book was released on 1974 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Theory of Turbulent Jets written by Genrikh Naumovich Abramovich and published by . This book was released on 1963 with total page 660 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Calculation of a Turbulent Axisymmetric Jet written by S. B. Jia and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book On the Prediction of Free Turbulent Jets with Swirl Using a Quadratic Pressure strain Model written by Bassam A. Younis and published by . This book was released on 1994 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Theoretical and Experimental Investigation of the Isothermal Axisymmetric Turbulent Free Jet written by David A. Bell and published by . This book was released on 1984 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Calculation Method for Incompressible Axisymmetric Flows Including Unseparated Fully Separated and Free Surface Flows written by James Webb White and published by . This book was released on 1975 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: An interacting zone method is developed for the analysis of completely stalled, turbulent, axisymmetric jet flows which are incompressible and nominally steady. The flow is treated as a mutual interaction problem; unlike the classical boundary layer theory, this method includes the effect of the stalled-zone blockage on the first order potential flow solution. Both a priori and ab initio predictions are obtained. A new integral turbulent boundary layer separation prediction method is developed in order to accurately predict the separation location and effective flow boundary near separation. Because the boundary layer equations require only the wall pressure from the potential flow, a new boundary integral solution is developed for the potential field. Unlike grid methods, the boundary integral method computes unknowns only over the flow boundary. By treating the stalled zone as a region of uniform (but initially unknown) pressure, the potential solution can iteratively locate the free surface. Speed of computation is significantly faster than existing grid methods for potential flow analysis. The resulting computer program provides analysis of the following types of axisymmetric flows: (1) Unseparated potential flow, with and without blowing or suction; (2) Free surface potential flow; (3) Unseparated turbulent diffuser flow; and (4) Completely separated turbulent jet flow. (Author).

Download or read book Computational Fluid Dynamics Prediction of Subsonic Axisymmetric and Two Dimensional Heated Free Turbulent Air Jets written by Michael D. DeWulf and published by . This book was released on 2000-09 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was conducted to evaluate the accuracy of a commercial computational fluid dynamics (CFD) code (CFDRC-ACE+) for predicting incompressible air jet flows with simple geometries. Specifically, the axis- symmetric and two-dimensional heated air-jets were simulated using a standard k- epsilon turbulence model. These CFD predictions were directly compared to an extensive compilation of experimental data from archive literature. The round jet results indicated that the code over-predicted the velocity-spreading rate by 24% and the temperature spreading rate by 29%.

Download or read book NASA Technical Note written by and published by . This book was released on 1976 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt: