Download or read book Stability and Unsteadiness of Transitional Shock wave boundary layer Interactions in Supersonic Flows written by Andrea Sansica and published by . This book was released on 2015 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 Laminar transitional shock wave boundary layer interactions SWBLIs in hypersonic flows written by Romie Oktovianus Bura and published by . This book was released on 2004 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 Direct and Large Eddy Simulation XII written by Manuel García-Villalba and published by Springer Nature. This book was released on 2020-05-09 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers the proceedings of the 12th instalment in the bi-annual Workshop series on Direct and Large Eddy Simulation (DLES), which began in 1994 and focuses on modern techniques used to simulate turbulent flows based on the partial or full resolution of the instantaneous turbulent flow structure. With the rapidly expanding capacities of modern computers, this approach has attracted more and more interest over the years and will undoubtedly be further enhanced and applied in the future. Hybrid modelling techniques based on a combination of LES and RANS approaches also fall into this category and are covered as well. The goal of the Workshop was to share the state of the art in DNS, LES and related techniques for the computation and modelling of turbulent and transitional flows. The respective papers highlight the latest advances in the prediction, understanding and control of turbulent flows in academic and industrial applications.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Determination of Effects of Frequency and Amplitude on the Lateral Stability Derivatives for a Delta a Swept and an Upswept Wing Oscillating in Yaw written by Dean R. Chapman and published by . This book was released on 1958 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Investigation of Shock Wave boundary Layer Interaction written by Raymond L. Chuan and published by . This book was released on 1955 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Shock Wave Interactions written by Konstantinos Kontis and published by Springer. This book was released on 2018-03-28 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: This edited monograph contains the proceedings of the International Shock Interaction Symposium, which emerged as an heir to both the Mach Reflection and Shock Vortex Interaction Symposia. These scientific biannual meetings provide an ideal platform to expose new developments and discuss recent challenges in the field of shock wave interaction phenomena. The goal of the symposia is to offer a forum for international interaction between young and established scientists in the field of shock and blast wave interaction phenomena. The target audience of this book comprises primarily researchers and experts in the field of shock waves, but the book may also be beneficial for young scientists and graduate students alike.
Download or read book Supersonic Separated Flows Over Wedges and Flares with Emphasis on a Method of Detecting Transition written by Jean J. Ginoux and published by . This book was released on 1968 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigation is a first step to the study of the effect of cross flow in laminar separation at supersonic speeds. It is related to the selection of a final axi-symmetric model. Several problems were examined. First, the effect of streamwise vortices that develop systematically in laminar reattaching flows, triggered by small irregularities in the leading edge thickness. Second, the choice of the diameter of the model such that the flow resembles that of an equivalent planar body, third the programming of Lees-Reeves theory on a 1130 IBM computer to perform a parametric study and finally the development of a new accurate technique or criteria to ascertain that fully laminar shock wave boundary layer interactions can be obtained. (Author).
Download or read book Relationship Between Transition and Modes of Instability in Supersonic Boundary Layers written by Jamal A. Masad and published by . This book was released on 1993 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Interactions Entre Ondes de Choc Et Couches Limites Dans Les Ecoulements Supersoniques Et Hypersoniques written by and published by . This book was released on 1993 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Shock-wave/boundary-layer interactions continue to be ubiquitous phenomena in supersonic and hypersonic aerodynamics, and their importance is often critical as, for example, for hypersonic controls and for air intakes in general. This is the reason for the continuous research efforts in this field, aiming at developing reliable methodologies for future vehicle design. Results from these programmes have been reported. The present course reviews the recent progress in this field. In particular, a large part of the course is devoted to swept interactions, both laminar and turbulent, including a discussion of the following topics: (1) The flowfield structure; (2) The scaling and similarity laws; (3) The effect of shock strength on flow features; (4) The effect of shock generator geometry for a given shock strength; (5) Experimental techniques, in particular optical techniques, for the investigation of swept interactions; and (6) Contributions of numerical simulations to the understanding of swept interactions. A limiting factor in the understanding and ability to predict shock wave/boundary-layer interactions is a good knowledge of turbulence behavior. A lecture is devoted specifically to hypersonic interactions."--DTIC.
Download or read book Stability and Transition in Shear Flows written by Peter J. Schmid and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: A detailed look at some of the more modern issues of hydrodynamic stability, including transient growth, eigenvalue spectra, secondary instability. It presents analytical results and numerical simulations, linear and selected nonlinear stability methods. By including classical results as well as recent developments in the field of hydrodynamic stability and transition, the book can be used as a textbook for an introductory, graduate-level course in stability theory or for a special-topics fluids course. It is equally of value as a reference for researchers in the field of hydrodynamic stability theory or with an interest in recent developments in fluid dynamics. Stability theory has seen a rapid development over the past decade, this book includes such new developments as direct numerical simulations of transition to turbulence and linear analysis based on the initial-value problem.
Download or read book Special Course on Shock Wave Boundary Layer Interactions in Supersonic and Hypersonic Flows Interactions Entre Ondes de Choc Et Couches Limites Dans Les Ecoulements Supersoniques Et Hpersoniques written by and published by . This book was released on 1993 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shock-wave/boundary-layer interactions continue to be ubiquitous phenomena in supersonic and hypersonic aerodynamics, and their importance is often critical as, for example, for hypersonic controls and for air intakes in general. This is the reason for the continuous research efforts in this field, aiming at developing reliable methodologies for future vehicle design. Results from these programmes have been reported. The present course reviews the recent progress in this field. In particular, a large part of the course is devoted to swept interactions, both laminar and turbulent, including a discussion of the following topics: (1) The flowfield structure; (2) The scaling and similarity laws; (3) The effect of shock strength on flow features; (4) The effect of shock generator geometry for a given shock strength; (5) Experimental techniques, in particular optical techniques, for the investigation of swept interactions; and (6) Contributions of numerical simulations to the understanding of swept interactions. A limiting factor in the understanding and ability to predict shock wave/boundary-layer interactions is a good knowledge of turbulence behavior. A lecture is devoted specifically to hypersonic interactions.
Download or read book Experimental Investigation of Induced Supersonic Boundary Layer Transition written by Henny Bottini and published by . This book was released on 2014 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence onset within an initially laminar flow is one of the most common phenomenon in Fluid Mechanics, yet is an open field of research. This is due to the many and diverse causes that can trigger turbulence, which often add to each other, change their effect upon the flow velocity, and are difficult to single out in real-world situations. This is why laminar-toturbulent transition experiments have been and still are a fundamental tool for the researcher. This thesis work has addressed the study of turbulence onset in supersonic flows from an experimental point of view. Two test campaigns have been carried out each in a dedicated supersonic wind tunnel. The first aimed at tracking turbulence onset triggered by a single tetrahedral roughness element. It has been carried out in a multiple-Mach-number supersonic wind tunnel whose qualification campaign has been completed within this thesis work. Two roughness heights were tested, both for two Mach numbers, 1.6 and 2.3. The second test campaign has investigated the effects of an oblique shock wave impinging onto a Mach-2 transitional boundary layer. The transitional state of a boundary layer is that state during which the boundary layer passes from fully laminar to fully turbulent. This passage can be either induced or natural, and it was represented in this thesis work by the trigger wake and by the boundary layer flow downstream of the release point of an electric spark, respectively. Surface sensors, as thin-films and piezoelectric pressure transducers, were used to measure steady and unsteady highfrequency flow evolutions. Different wall temperatures were set for the thin-films insert as to allow the experimental estimation of the recovery temperature. Convective heat-flux trends have been extracted from the steady measurements, which, together with the recovery temperature trends, allowed the calculation of the Stanton number trends. All these quantities let to conclude on the general state of the boundary layer investigated in the first test campaign. The post-processing of the unsteady measurements yielded temperature and pressure fluctuations spectra and RMS streamwise evolutions, along with spectral time evolution at a given position. For the first test campaign, they allowed the characterization of the unsteadiness produced by the roughness within the supersonic boundary layer at different downstream locations. In so doing, they helped conclude on the state of the boundary layer, thus on the effectiveness of the roughness in triggering transition to turbulence. For the second test campaign, they allowed to single out the unsteady effects of the shock impinging downstream of the single roughness and downstream of the electric spark release point. In this way, differences in the shock effect between the roughness configuration and the clean-plate configuration have been highlighted, and the effects of different spark release frequencies compared.
