Download or read book Numerical Investigation of Transitional and Turbulent Compressible Axisymmetric Wakes PHD written by Dietmar 1964 Tourbier and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Investigation of Separated Transonic Turbulent Flows with a Multiple time scale Turbulence Model written by S. W. Kim and published by . This book was released on 1990 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Investigation of Laminar Turbulent Transition in a Flat Plate Wake written by Hermann F. Fasel and published by . This book was released on 1990 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lamina-turbulent transition of high-deficit flat plate wakes is investigated by direct numerical simulations using the complete Navier Stokes equations. The simulations are based on a spatial model so that both the base flow and the disturbance flow can develop in the downstream direction. The Navier Stokes equations are used in a vorticity-velocity form and are solved using a combination of finite difference and spectral approximations. Fourier series are used in the spanwise direction. Second-order finite-differences are used to approximate the spatial derivatives in the streamwise and transverse directions. For the temporal discretion, a combination of ADI, Crank-Nicolson, and Adams-Bashforth methods is employed. The discretized velocity equations are solved using fast Helmholtz solvers. Code validation is accomplished by comparison of the numerical results to both linear stability and to experiments. Calculations of two- and/or three-dimensional sinuous and mode disturbances in the wake of flat plate are undertaken. For calculations of two-dimensional disturbances, the wake is forced at an amplitude level so that nonlinear disturbance development may be observed. In addition, the forcing amplitude is varied in order to determine its effect on the disturbance behavior. To investigate the onset of three-dimensionality, the wake is forced with a small-amplitude three-dimensional disturbance and a larger amplitude two-dimensional disturbance. The two-dimensional forcing amplitude is varied in order to determine its influence on the three-dimensional flow field. (jhd).
Download or read book Analysis of Turbulent Flows with Computer Programs written by Tuncer Cebeci and published by Butterworth-Heinemann. This book was released on 2013-02-26 with total page 465 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analysis of Turbulent Flows is written by one of the most prolific authors in the field of CFD. Professor of Aerodynamics at SUPAERO and Director of DMAE at ONERA, Professor Tuncer Cebeci calls on both his academic and industrial experience when presenting this work. Each chapter has been specifically constructed to provide a comprehensive overview of turbulent flow and its measurement. Analysis of Turbulent Flows serves as an advanced textbook for PhD candidates working in the field of CFD and is essential reading for researchers, practitioners in industry and MSc and MEng students. The field of CFD is strongly represented by the following corporate organizations: Boeing, Airbus, Thales, United Technologies and General Electric. Government bodies and academic institutions also have a strong interest in this exciting field. An overview of the development and application of computational fluid dynamics (CFD), with real applications to industry Contains a unique section on short-cut methods – simple approaches to practical engineering problems
Download or read book Analysis of Weakly Compressible Turbulence Using Symmetry Methods and Direct Numerical Simulation written by Raphael Gotthard Harald Arlitt and published by Cuvillier Verlag. This book was released on 2005 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2007 with total page 1184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Investigation of Momentumless Wakes in Stratified Fluids written by Kyle Ashley Brucker and published by . This book was released on 2009 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dissertation focuses on a comparison between momentumless (self-propelled) and net-momentum (towed) wakes with an emphasis on the elucidation of buoyancy effects. It is difficult to realize truly momentumless wakes in the laboratory and DNS offer a viable, accurate alternative because the initial value of net momentum can be controlled and the evolution of the net momentum can be closely monitored. DNS of axisymmetric wakes with and without net momentum are performed at Re=50,000 on a grid with approximately 2 billion grid points. The development of the wake is characterized by the evolution of maxima, area integrals and spatial distributions of mean and turbulence statistics. The mean velocity in the self-propelled, momentumless wake decays more rapidly than the towed case due to higher shear and consequently a faster rate of energy transfer to turbulence. Buoyancy allows a wake to survive longer in a stratified fluid by reducing the u1'u3' correlation responsible for the mean-to-turbulence energy transfer in the vertical direction. This buoyancy effect is especially important in the self-propelled case because it allows regions of positive and negative momentum to become decoupled in the vertical direction and decay with different rates. The vertical wake thickness is found to be larger in self-propelled wakes. The role of internal waves in the energetics is determined and it is found that they are responsible for sustaining turbulence at the wake periphery long after the shear production has subsided. The non-equilibrium region of the Re=50,000 wake is found to exhibit a time span when, although the turbulence is strongly stratified as indicated by small Froude number, the turbulent dissipation rate exhibits inertial scaling. The multiply inflected mean velocity profile, inherent to the self-propelled wake, results in four bands of vorticity, compared to the two bands observed in the towed case. Vortex pairs of opposite sign form vortex dipoles which interact with other dipoles to cause a more disordered appearance of the late wake vorticity when compared to the towed case.
Download or read book Laminar Wakes written by Stanley A. Berger and published by . This book was released on 1971 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive survey is given of the state of knowledge of steady, nonturbulent laminar fluid wakes behind both blunt and slender bodies in viscous fluids, with emphasis on high-speed wakes. The flows are generally assumed to occur at large but finite free-stream Reynolds numbers, generally with a thin boundary layer on the body. Compressible and viscous flow theory are involved. The focus is on basic theory and concepts; both experimental results and speculative theories are given only where they provide greater insight or information otherwise unavailable. Transition and turbulence problems are not discssed.
Download or read book Proceedings of the 4th ASME JSME Joint Fluids Engineering Conference written by Ali Ogut and published by . This book was released on 2003 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Investigation of Turbulence and Mixing in Shock accelerated Compressible Multi component Flows written by Santhosh Kumar Shankar and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The problem of Richtmyer-Meshkov instability is numerically studied in canonical configuration. The discontinuities in the flow field (such as shock waves, contact surfaces and material interfaces) are captured by using a shock-capturing method coupled with a high-order high-resolution compact differencing scheme. Verification and validation is conducted by simulating 1-D and 2-D canonical test problems and comparing the numerical results with experimental data and previous numerical results. High resolution numerical simulation of the impulsive acceleration of a dense gas curtain in air by a Mach 1.21 planar shock (modeling the experiments by Balakumar et al. PoF 2008) is carried out by solving the 3-D compressible multi-species Navier-Stokes equation coupled with a localized artificial diffusivity method to capture discontinuities in the flow-field. The simulations account for the presence of three species in the flow-field: air, SF6 and acetone (used as a tracer species in the experiments). The reshock process is studied by re-impacting the evolving curtain with a reflected shock wave. Turbulence statistics computed in the flow-field following reshock are reported and compared with experiment where possible. Inertial range scaling, vorticity anisotropy and Reynolds stress development are studied in the reshocked flow. The high resolution data set is used to test certain modeling assumptions appearing in mixing models (BHR model) that have been traditionally used to study variable density flows. Finally preliminary results are shown from a 3-dimensional calculation of a planar shock interacting with a planar perturbed interface between air and SF6.
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1998 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2005 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 41st AIAA Aerospace Sciences Meeting Exhibit written by and published by . This book was released on 2003 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Computation of Shock Wave turbulent Boundary Layer Interaction in Transonic Flow Over an Axisymmetric Curved Hill written by S.-W. Kim and published by . This book was released on 1989 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mean Flow Measurements in an Axisymmetric Compressible Turbulent Wake written by A. Demetriades and published by . This book was released on 1967 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mean flow field of the axisymmetric turbulent wake shed by a very slender body at Mach 3 has been mapped with the aid of the pitot and static pressure probes and the hot-wire anemometer. The experimental geometry was chosen so that no inviscid wake existed, and the measurements were carried out to about 100 diameters downstream of the base. The axial variation of the velocity and temperature defects appears to obey classical decay laws following a relaxation distance of at least 40 diameters from the transition region. By contrast, the radial profiles of these properties relax quickly to a self-preserving form; both the temperature and the velocity radial variations fit single-parameter Gaussian distributions quite well. The proper radial similarity variable is the radius divided by the transverse wake scale; equally good agreement obtains for a Howarth-Dorodnitzyn-transformed radius, although this issue is still unsettled because of the low Mach number used. The turbulent Reynolds and Prandtl numbers computed indirectly from the data agree well with similar results from low-speed turbulent flows. (Author).
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 Transition Location Effect on Shock Wave Boundary Layer Interaction written by Piotr Doerffer and published by Springer. This book was released on 2021-08-01 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents experimental and numerical findings on reducing shock-induced separation by applying transition upstream the shock wave. The purpose is to find out how close to the shock wave the transition should be located in order to obtain favorable turbulent boundary layer interaction. The book shares findings obtained using advanced flow measurement methods and concerning e.g. the transition location, boundary layer characteristics, and the detection of shock wave configurations. It includes a number of experimental case studies and CFD simulations that offer valuable insights into the flow structure. It covers RANS/URANS methods for the experimental test section design, as well as more advanced techniques, such as LES, hybrid methods and DNS for studying the transition and shock wave interaction in detail. The experimental and numerical investigations presented here were conducted by sixteen different partners in the context of the TFAST Project. The general focus is on determining if and how it is possible to improve flow performance in comparison to laminar interaction. The book mainly addresses academics and professionals whose work involves the aerodynamics of internal and external flows, as well as experimentalists working with compressible flows. It will also be of benefit for CFD developers and users, and for students of aviation and propulsion systems alike.
