Download or read book Unsteadiness of Shock Wave Boundary Layer Interactions Across Multiple Interaction Configurations and Strengths written by James Threadgill and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Unsteadiness in Shock wave boundary layer Interactions written by Emile Touber and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book On the Scaling and Unsteadiness of Shock Induced Separation written by Louis Jacques Souverein and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shock wave boundary layer interactions (SWBLI) are a common phenomenon in transonic and supersonic flows. The presence of shock waves, induced by specific geometrical configurations, cause a rapid increase of the pressure, wich can lead to flow separation. Examples of such interaction are found in amongts other rocket engine nozzles, on re-entry vehicles, in supersonic and hypersonic engine intakes, and at the tips of compressor and turbine blades. The interactions are important factors in vehicle development. Both the separated flow and the induced shock have been shows to be highly unsteady, causing pressure fluctuations and thermal loading. This generally leads to a degraded performance and possibly structural failure. The current work therefore aims to improve the physical understanding of the mechanisms that govern the interaction, with a special attention for the flow organisation and for the sources of the unsteadiness of the induced shock. Additioinally, it is verified wether the interaction can be controlled by means of upstream fluid injection. PIV measurements were performed, comparing several interactions for a range of shock intensities for a number of Mach and Reynolds numbers. It is proposed that relative importance of the different unsteadiness mechanisms (upstream, downstream) shifts with the imposed shock intensity. The onset of separation is Reynolds number independent for turbulent boundary layers. The interaction length is however governed by the both the Reynolds number and the Mach number.

Download or read book Transition Location Effect on Shock Wave Boundary Layer Interaction written by Piotr Doerffer and published by Springer Nature. This book was released on 2020-07-30 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.

Download or read book Unsteadiness of Shock Wave turbulent Boundary Layer Interactions with Dynamic Control written by Michael S. Selig and published by . This book was released on 1988 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Investigation of Shock Wave turbulent Boundary Layer Interactions with and Without Boundary Layer Suction written by C. C. Sun and published by . This book was released on 1977 with total page 916 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tabulated data from a series of experimental studies of the interaction of a shock wave with a turbulent boundary layer in axisymmetric flow configurations is presented. The studies were conducted at the walls of circular wind tunnels and on the cylindrical centerbody of an annular flow channel. Detailed pitot pressure profiles and wall static pressure profiles upstream of, within and downstream of the interaction region are given. Results are presented for flows at nominal freestream Mach Numbers of 2, 3 and 4. For studies at the tunnel sidewalls, the shock waves were produced by conical shock generators mounted on the centerline of the wind tunnel at zero angle of attack. The annular ring generator was used to produce the shock wave at the centerbody of the annular flow channel. The effects of boundary layer bleed were examined in the investigation. Both bleed rate and bleed location were studied. Most of the bleed studies were conducted with bleed holes drilled normal to the wall surface but the effects of slot suction were also examined. A summary of the principal results and conclusions is given.

Download or read book Calculation of Unsteady Transonic Flows with Mild Separation by Viscous inviscid Interaction written by James T. Howlett and published by . This book was released on 1992 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Tactical Missile Aerodynamics written by and published by . This book was released on 1992 with total page 731 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Theoretical Investigation of 3 D Shock Wave Turbulent Boundary Layer Interactions written by Doyle Knight and published by . This book was released on 1988 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research describes continuing efforts in the analysis of 3-D shock wave turbulent boundary layer interactions. A significant research activity in 3-D hypersonic shock turbulent interactions is initiated to further develop and validate the theoretical model. The quasiconical free interaction principle is examined by simulation of two geometries -17.5 deg sharp fin and (30,60) swept compression corner (Mach 3) - selected to obtain similar shock strengths. The comparison with experimental data is good. It is confirmed that the differences caused by the particular geometry of the model appear only behind the inviscid shock wave. Continuing research on 3-D turbulent interaction control is focused on the effect of bleed and the simulation of flows past the double-fin configuration. The effect of suction is examined on a strong (fin angle=20 deg, Mach 3) and a weak interaction (8 deg, Mach 3). The overall effect of bleed is remarkably modest. Two double-fin configurations (4 x 4 and 8 x 8, Mach 3) are simulated. A study of the computed flowfield indicates that the first is a weak interaction. In contrast, the 8 x 8 configuration displays an interesting separated flowfield. An analysis of viscous and inviscid effects in a sharp fin and a swept corner flow indicates that the physics of both geometries are governed primarily by inviscid (pressure) effects. Viscous effects are of lower magnitude but are not restricted to the sublayer region. High speed flows; Viscous inviscid interactions; Boundary layer interactions; Computational fluid dynamics; Navier stokes equations; Turbulence.(mjm).

Download or read book A Study of Unsteadiness of Shock Wave turbulent Boundary Layer Interactions from Fluctuating Wall Pressure Measurements written by T. T. Tran and published by . This book was released on 1987 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Research on Crossing Shock Wave Boundary Layer Interactions written by and published by . This book was released on 1994 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental research effort of the Penn State Gas Dynamics Laboratory on the subject of crossing shock wave boundary layer interactions is reported. This three year study was supported by AFOSR Grant 89-0315. A variety of experimental techniques were employed to study the above phenomena including planar laser scattering flowfield visualization, kerosene lampblack surface flow visualization, laser-interferometer skin friction surveys, wall static pressure measurements, and flowfield five-hole probe surveys. For a model configuration producing two intersecting shock waves, measurements were made for a range of oblique shock strengths at freestream Mach numbers of 3.0 and 3.85. Additionally, measurements were made at Mach 3.85 for a configuration producing three intersecting waves. The combined experimental dataset was used to formulate the first detailed flowfield models of the crossing-shock and triple-shock wave/boundary layer interactions. The structure of these interactions was found to be similar over a broad range of interaction strengths and is dominated by a large, separated, viscous flow region. (AN).

Download or read book Interaction of Two Glancing Crossing Shock Waves with a Turbulent Boundary Layer at Various Mach Numbers written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-08 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: A preliminary experimental investigation was conducted to study two crossing, glancing shock waves of equal strengths, interacting with the boundary-layer developed on a supersonic wind tunnel wall. This study was performed at several Mach numbers between 2.5 and 4.0. The shock waves were created by fins (shock generators), spanning the tunnel test section, that were set at angles varying from 4 to 12 degrees. The data acquired are wall static pressure measurements, and qualitative information in the form of oil flow and schlieren visualizations. The principle aim is two-fold. First, a fundamental understanding of the physics underlying this flow phenomena is desired. Also, a comprehensive data set is needed for computational fluid dynamic code validation. Results indicate that for small shock generator angles, the boundary-layer remains attached throughout the flow field. However, with increasing shock strengths (increasing generator angles), boundary layer separation does occur and becomes progressively more severe as the generator angles are increased further. The location of the separation, which starts well downstream of the shock crossing point, moves upstream as shock strengths are increased. At the highest generator angles, the separation appears to begin coincident with the generator leading edges and engulfs most of the area between the generators. This phenomena occurs very near the 'unstart' limit for the generators. The wall pressures at the lower generator angles are nominally consistent with the flow geometries (i.e. shock patterns) although significantly affected by the boundary-layer upstream influence. As separation occurs, the wall pressures exhibit a gradient that is mainly axial in direction in the vicinity of the separation. At the limiting conditions the wall pressure gradients are primarily in the axial direction throughout. Hingst, Warren R. and Williams, Kevin E. Glenn Research Center...

Download or read book Investigations into the causes of unsteadiness of shock wave turbulent boundary layer interactions using planar laser scattering written by Mark Comninos and published by . This book was released on 1997 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 On Unsteadiness in 2 D and 3 D Shock Wave Turbulent Boundary Layer Interactions written by Mbu Waindim and published by . This book was released on 2017 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: The most substantial outcome of this work is the insight obtained regarding the dynamics of the swept interaction. The results show that: (i) The shock generated by the fin is anchored unlike the oscillating reflected shock in 2-D; consequently, the low frequencies observed in 2-D are not present in this swept interaction. (ii) A convective inviscid instability is identified at a frequency an order of magnitude higher than the characteristic frequency of shock motions in 2-D. It is shown to be a consequence of the crossflow and analogous to the mid frequencies associated with K-H shedding in the 2-D interaction. (iii) The absolute instability observed in 2-D does not persist here as the absence of a closed separation reduces the interaction’s ability to perpetually self-sustain introduced perturbations.