Download or read book ANALYSIS OF UNSTEADY TRANSONIC CHANNEL FLOW WITH SHOCK WAVES written by GEORGE KEITH RICHEY and published by . This book was released on 1975 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: Inviscid unsteady transonic flow in a two-dimensional channel is analyzed using asymptotic techniques. The analysis includes the case where a shock wave is present in a channel having arbitrary wall shape, with artibrary small disturbances imposed at a given downstream location. Second-order solutions are not uniformly valid near the shock wave, since they do not satisfy the shock jump conditions. It is therefore necessary to obtain inner solutions which are matched asymptotically to those in the outer channel-flow region.
Download or read book A Study of Unsteady Transonic Flows with Shock Waves in Two Dimensional Channels written by T. C Adamson (Jr) and published by . This book was released on 1972 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: A two dimensional unsteady transonic flow of a perfect gas with constant specific heats is considered, with solutions found in the form of perturbations from a uniform, sonic, isentropic flow. Longitudinal viscous stress terms are included so that shock waves can be considered. The case where the characteristic time of a temporal flow disturbance is large compared to the time taken by a sonic disturbance to cross the transonic regime is considered. A similarity solution involving an arbitrary function of time is found and it is shown that this solution corresponds to unsteady channel flows with shock waves, for the case where the walls are in general not stationary. Solutions are presented for thick (shock fills transonic region) and thin (shock tends to a discontinuity) shock waves in unsteady flows, both for decelerating and accelerating channel flows. For the thin shock case, both numerical and asymptotic solutions are given. (Author).
Download or read book Unsteady Transonic Flow in Two Dimensional Channels written by T. C Adamson (Jr) and published by . This book was released on 1978 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unsteady transonic flow with a shock wave in a two-dimensional channel is considered. Solutions valid in a thin inner region enclosing the nozzle throat, where previous solutions showed singular behavior, are presented. A brief description of a computer movie is given; this movie shows solutions for unsteady transonic channel flow for two different cases in which the shock wave, as a result of pressure oscillations impressed downstream of the nozzle throat, moves to and upstream of the throat, disappears, and reforms at the throat. An analysis showing how results derived for the interaction between a shock wave and a turbulent boundary layer in steady flow may be used in the corresponding quasi-steady flow problem, is presented; a discussion of how these results may be used to deduce the order of the distance from the shock wave to the separation point and the time characteristic of the life of a shock induced separation bubble in unsteady flow is given. (Author).
Download or read book A Study of the Transient Behavior of Shock Waves in Transonic Channel Flows written by Robert V. Hess and published by . This book was released on 1952 with total page 734 pages. Available in PDF, EPUB and Kindle. Book excerpt: The accuracy of the result obtained in a fundamental paper by Kantrowitz (NACA TN 1225) that a small short-time lowering of the back pressure in steady, shock-free, transonic diffuser flow causes a stationary or trapped shock to form near the critical sonic channel throat is investigated by considering the contribution of a higher-order term in the short-time calculations which was neglected in Kantrowitz's paper. In this higher approximation to the short-time effects, the shock is no longer stationary or trapped unless it is supported by a negative steady-flow back pressure; the result thus is no long in disagreement with steady-flow solutions for stationary shocks.
Download or read book Unsteady Motion of Shock Waves in Two Dimensional Transonic Channel Flows written by T. C Adamson (Jr) and published by . This book was released on 1977 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two dimensional unsteady transonic channel flow with a shock wave is considered for the so-called slowly varying time regime. Solutions are studied for two specific cases within this general time regime, the cases corresponding to small and large amplitude shock wave motions. For the large amplitude case, conditions are considered under which the shock wave travels upstream of the throat, disappears, and then reforms at the throat. A unified solution which covers both cases is developed. Numerical results are presented. A short discussion of shock induced separation in unsteady flows is given. (Author).
Download or read book Unsteadiness in Transonic Shock wave boundary Layer Interactions written by Fulvio Sartor and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A transonic interaction between a shock wave and a turbulent boundary layer is experimentally and theoretically investigated. The configuration is a channel flow over a bump, where a shock wave causes the separation of the boundary layer and a recirculating bubble is observed downstream of the shock foot.The mean flow is experimentally investigated by means of PIV, then different techniques allows to identify the main unsteadiness of this shock-wave/boundary-layer interaction. As recognised in similar configurations, the flow presents two distinguished characteristic frequencies, whose origins are still unknown.Numerical simulations are performed solving RANS equations. Results are in good agreement with the experimental mean flow, but the approach fails to predict the unsteady. The solution of RANS equations is then considered as a base flow, and a global stability analysis is performed. Eigenvalue decomposition of the Navier-Stokes operator indicates that the interaction is stable, and the dynamics cannot be described by unstable global modes.A linearised approach based on a singular-value decomposition of the Resolvent is then proposed: the noise-amplifier behaviour of the flow is highlighted by the linearised approach. Medium-frequency perturbations are shown to be the most amplified in the mixing layer, whilst the shock wave behaves as a low-pass filter.The same approach is then applied to a transonic flow over a profile, where the flow can present high-amplitude shock oscillations. The stability analysis can describe both the buffet phenomenon when an unstable mode is present, and the convective instabilities responsible of medium-frequency unsteadiness.
Download or read book Shock Wave Boundary Layer Interactions written by Holger Babinsky and published by Cambridge University Press. This book was released on 2011-09-12 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shock wave-boundary-layer interaction (SBLI) is a fundamental phenomenon in gas dynamics that is observed in many practical situations, ranging from transonic aircraft wings to hypersonic vehicles and engines. SBLIs have the potential to pose serious problems in a flowfield; hence they often prove to be a critical - or even design limiting - issue for many aerospace applications. This is the first book devoted solely to a comprehensive, state-of-the-art explanation of this phenomenon. It includes a description of the basic fluid mechanics of SBLIs plus contributions from leading international experts who share their insight into their physics and the impact they have in practical flow situations. This book is for practitioners and graduate students in aerodynamics who wish to familiarize themselves with all aspects of SBLI flows. It is a valuable resource for specialists because it compiles experimental, computational and theoretical knowledge in one place.
Download or read book Unsteady Effects of Shock Wave induced Separation written by Piotr Doerffer and published by Springer Science & Business Media. This book was released on 2010-11-25 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains description of experimental and numerical results obtained in the UFAST project. The goal of the project was to generate experiment data bank providing unsteady characteristics of the shock boundary layer interaction. The experiments concerned basic-reference cases and the cases with application of flow control devices. Obtained new data bank have been used for the comparison with available simulation techniques, starting from RANS, through URANS, LES and hybrid RANS-LES methods. New understanding of flow physics as well as ability of different numerical methods in the prediction of such unsteady flow phenomena will be discussed.
Download or read book Two dimensional Transonic Unsteady Flow with Shock waves written by Wiktor Eckhaus and published by . This book was released on 1959 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Unsteady Transonic Small Disturbance Theory with Strong Shock Waves written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-20 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: A theory to correct the transonic small disturbance (TSD) equation to treat strong shock waves in unsteady flow is developed. The technique involves the addition of higher order terms, which are formally of negligible magnitude, to the low frequency TSD equation. These terms are then chosen such that any shock waves in the flow have strengths approximately equal to the appropriate Rankine-Hugoniot shock strength. Two correcting approaches are investigated. The first is to derive a correction for the mean steady flow and then simply use this corrected form for oscillatory flows. The second is to derive a correction for both steady and oscillatory parts of the flow. This second development is the most satisfactory and comparisons of the present results with Euler equation results are generally favorable, particularly regarding shock location, although there are some discrepancies in the pressure distribution in the leading edge region. Kerlick, G. D. and Nixon, D. and Ballhaus, W. F., Jr. Ames Research Center NASA-CR-166157, NEAR-TR-230 NASA ORDER A-70215-B; NASA ORDER A-77455-B
Download or read book A Nonlinear Theory for Predicting the Effects of Unsteady Laminar Turbulent Or Transitional Boundary Layers on the Attenuation of Shock Waves in a Shock Tube with Experimental Comparison written by Robert L. Trimpi and published by . This book was released on 1958 with total page 682 pages. Available in PDF, EPUB and Kindle. Book excerpt: The linearized attenuation theory of NACA Technical Note 3375 is modified in the following manner: (a) an unsteady compressible local skin-friction coefficient is employed rather than the equivalent steady-flow incompressible coefficient; (b) a nonlinear approach is used to permit application of the theory to large attenuations; and (c) transition effects are considered. Curves are presented for predicting attenuation for shock pressure ratios up to 20 and a range of shock-tube Reynolds numbers. Comparison of theory and experimental data for shock wave strengths between 1.5 and 10 over a wide range of Reynolds numbers shows good agreement with the nonlinear theory evaluated for a transition Reynolds nuniber of 2.5 million.
Download or read book Boundary Value Problems for Transonic Flow written by Alexander G Kuz'min and published by John Wiley & Sons. This book was released on 2003-02-28 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transonic flow occurs around moving objects as they approach and cross the sound barrier. Serious problems can occur at this point, such as shock-induced flow separation which can cause the aircraft to spin out of control. Another important practical problem is the achievement of higher aerodynamic performance of aircraft at cruise conditions, which leads to considerable fuel savings. The success in application of numerical methods for simulation of transonic flow and aircraft design depends on developments in the underlying mathematical theory. This book presents a breakthrough in the solvability analysis of boundary value problems, which makes it possible to establish convergence of finite element approximations for shock-free flow and to provide a framework for putting the existing numerical methods on a more sound basis. Also, physical aspects concerned with patterns of formation and propagation of weak shock waves are analysed. This contributes to the understanding of the extreme sensitivity of transonic flow to perturbation of freestream conditions. The developed theoretical knowledge base yields promising concepts of the airfoil design and active flow control by airfoil/wing shape modifications or suction/blowing through a perforated surface. Boundary Value Problems for Transonic Flow * Focuses on Computational Fluid Dynamics. * Addresses practical problems, such as airfoil design and flow control. * Presents developments made in the last two decades. In essence this is a much needed monograph for researchers and engineers in applied mathematics and numerical analysis applied to aerodynamics and for algorithm developers in Computational Fluid Dynamics in the aircraft industry. It gives design engineers the underlying mathematical theory necessary for developing new concepts for airfoil/wing design and flow control.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book STAR written by and published by . This book was released on 1973 with total page 888 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of the Mechanism of Transonic Shock Wave Boundary Layer Interactions Using a Navier Stokes Analysis written by D. V. Roscoe and published by . This book was released on 1984 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present report discusses the development of a time-dependent Navier-Stokes code for use in predicting transonic shock-wave boundary layer interaction. In addition, various test cases which have been performed are discussed. The algorithm used to solve the equations is based upon the consistently split linearized block implicit method of Briley and McDonald (15, 16). The philosophy and use of a solution adaptive mesh is also described. The test cases studied in this report are: normal shock wave boundary layer interaction in a constant area circular pipe, steady transonic flow over an axisymmetric bump, unsteady flow over an axisymmetric bump, supersonic flow over an axisymmetric compression corner and oblique shock wave impingement on a flat plate boundary layer. (Author).
Download or read book Analysis of Imbedded Transonic Shock Wave Influence on Turbulent Boundary Layer Separation written by J. E. Carter and published by . This book was released on 1982 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: A strong viscous-inviscid interaction model has been developed for predicting the detailed properties of the flow in the vicinity of an imbedded transonic shock wave interacting with a turbulent boundary layer in cases where the shock wave is of sufficient strength to result in flow separation. In this interaction model the inviscid flow is analyzed with a compressible stream function analysis specifically developed for mixed subsonic-supersonic flow regions. In the present effort this analysis has been extended to include upstream vorticity effects and the boundary-layer displacement effects. Numerous calculations are presented which demonstrates the capability of this analysis to predict transonic rotational flow. The viscous analysis in this interaction model is a newly developed inverse boundary-layer analysis which accounts for normal pressure gradients and imbedded shock waves. The equations are solved with a coupled implicit finite-difference scheme subject to the condition that the flow at the edge of viscous layer merges asymptotically with the outer inviscid flow. A model problem has been analyzed with this generalized inverse boundary-layer procedure and no stability problems were encountered.
Download or read book Transonic Symposium Theory Application and Experiment written by and published by . This book was released on 1989 with total page 964 pages. Available in PDF, EPUB and Kindle. Book excerpt:
