Download or read book Experimental Characterization and Flowfield Analysis of a Swept Shock Wave Boundary Layer Interaction written by Andrew Kyle Baldwin and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shockwave boundary layer interactions (SBLI) occur on both internal and external surfaces and adversely affect both the structural and propulsive performance of high-speed flight vehicles operating in the trans/super/hypersonic flow regimes. In the absence of a comprehensive understanding of the flow physics associated with SBLI, the most common approach to mitigating the negative ramifications is structural over-design, often resulting in reduced aero-propulsion efficiencies and excessive cost. SBLI have been the subject of numerous experimental and numerical investigations focusing on simplified two-dimensional (2-D) canonical configurations derived from relatively complicated aircraft/turbomachinery components. A few recent studies have focused on addressing the knowledge gaps by examining component geometries that produce three-dimensional (3-D) SBLI and therefore a closer representation of real-world configurations. The current experimental investigation explores the viscous/inviscid interaction of an incoming supersonic turbulent boundary layer and a single, sharp unswept fin generated shockwave. This kind of SBLI is of keen interest to the high-speed aerodynamics community as the separated flow induces a strong crossflow component, giving rise to a highly 3-D flowfield. Although previous studies on 3-D SBLI have provided a substantial knowledge base, there are still a number of consequential questions pertaining to the flowfield topology and dynamical behavior that remain unanswered. First, what is the effect of Reynolds number on SBLI flow features, in particular, the length scales associated with the shock-induced separation region and its interaction with the shock generator (sharp-fin)? Second, what is the extent of facility dependence on the 3-D SBLI? Which, if any, component(s) of the unsteadiness is inherent to the interaction and which are facility dependent and therefore limit or bias the flowfield? Are the geometric and boundary layer constraints imposed by the size of the facility necessary for numerical simulations to ensure the proper development of scaling parameters as experiments shift from the laboratory scale to flight testing. Finally, how do the spatio-temporal scales associated with SBLI vary with the interaction strength? The main objective of the present experimental study is to answer the posed questions by conducting a detailed flowfield analysis of the sharp fin induced SBLI over a range of Reynolds numbers and interaction strengths. The research methodology involves high-fidelity experiments at the state-of-the-art wind tunnel facilities housed at the Florida Center for Advanced Aero-Propulsion at Florida State University and the data available from previously published literature. Cutting-edge global flowfield diagnostics allow for the full-field reconstruction of both skin friction (mean) and pressure (time-averaged/unsteady) underneath the single fin SBLI as the incoming Mach number (M[infinity] = 2 - 4), fin angle of attack ([alpha]F = 10° - 20°), and unit Reynolds number (Re/m 17 x 106 - 108 x 106) are parametrically varied. Reynolds number sweeps, spanning nearly an order of magnitude, illustrate that the interaction footprint is distinctly affected by the Reynolds number, with the effects being most prominent near the fin/surface junction and the outer edges of the interaction near the freestream boundary. The results indicate that the interaction flowfield becomes less receptive to Reynolds number variations as the Reynolds number continues to increase. This shrinking dependence indicates that there may be a point beyond which any further increases to the Reynolds number produce negligible differences in the flowfield id est Reynolds number independence. Identical surface oil flow and pressure measurements carried out in facilities of different scale/size compare favorably throughout the interaction region with Reynolds number based scaling. However, different incoming boundary layer thicknesses impose limitations on the extent of the inception region and the onset of finite fin effects. When investigating the mean skin friction between different scale facilities, the Reynolds number scaling could not be assessed due to limitations of the available data sets. An angular scaling was applied to enable proper inter-facility comparison between the conical regions of both identically matching and nominally equivalent interaction strength test cases. The results showed trends similar to those seen in the pressure measurements, with skin friction matching well between the facilities across the interaction with minor divergences in the near fin region, where viscous effects become more prominent. Simultaneously sampled high-speed pressure transducers and fast response PSP measurements allowed for a full-field investigation of the flow dynamics. The RMS pressure field highlights regions of increased unsteadiness along the interaction boundary, inviscid shock line and at/upstream of the fin tip vertex. Increased coherence levels indicate a communication mechanism is present between the inviscid shock and the interaction boundary. When compared with studies conducted in a smaller facility, findings of the current work are consistent in both the locations of increased unsteadiness and their respective magnitudes. In addition to illustrating the robustness of these dynamical features between differing size facilities, the current work identifies the presence of elevated levels of low-frequency content. The presence of this low-frequency content has been observed in investigations associated with 2-D SBLI, but has been absent in the 3-D SBLI studies conducted in smaller facilities. The present study has contributed significantly to a better understanding of swept 3-D SBLI, in particular, the role of Reynolds number and the size of facility on the interaction characteristics. The flowfield analysis has discovered the underlying physics associated with the fin induced SBLI. The high-fidelity experimental database generated will be very useful for the validation of numerical tools and the development of flight vehicle design guidelines.
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 Experimental Research on Swept Shock Wave Boundary Layer Interactions written by Gary S. Settles and published by . This book was released on 1987 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments were carried out to assess Mach number effects on boundary layer due to generic fin and swept compression corner geometries. An extensive set of fin interaction experiments was carried out at constant Reynolds number over the Mach number range of 2.5 to 4.0. Data thus far consist of surface flow visualization photographs and laser light-screen visualizations of flowfield structure. Additional experiments were conducted to assess the possibility that experimental data of this type might depend on the wind tunnel facility in which the experiments were performed. That was not found to be the case. Results of the parametric Mach number study revealed that Mach number effects over the range considered are essentially inviscid. These were accounted for simply by referencing measured quantities to the freestream Mach angle. The interaction growth with increasing shock strength was found to be nonlinear, contrary to previous results. Initial results from swept compression corner experiments are also reported. Keywords: High speed flows; Viscous inviscid interactions; Supersonic flow; Flow visualization; Fluid dynamics; Flow separation.
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 Flowfield Analysis for Successive Oblique Shock Wave turbulent Boundary Layer Interactions written by Chen-Chih Sun and published by . This book was released on 1976 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Study of Shock Wave and Turbulent Boundary Layer Interactions written by Seymour M. Bogdonoff and published by . This book was released on 1986 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: The three dimensional shock wave turbulent boundary layer interaction generated by several shock generators defined solely by angles has been carried out at a Mach number of 3. Interactions with thin boundary layers were used to obtain overall characteristics, while interactions with thick boundary layers permitted detailed high resolution surveys. Investigations of the interactions were carried out by mean and high frequency surface pressure distribution measurements, surface flow visualization, and mean total head, yaw, and static pressure distributions through the flowfield. Major new data sets were obtained for the interaction of the shock wave generated by a 20 deg fin, and by a 24 deg wedge swept at 60 deg to the incoming flow. A series of tests were carried out to examine new concepts of three-dimensional interactions and extensive 'non-steady' results were obtained from the high frequency surface pressure distributions. Close coordination of the experiments with major computational efforts, support new concepts of flow structure and physics for these complex interactions. Keywords: Three-dimensional shock wave interactions; Conical similarity; Scaling laws; Conical/cylindrical boundary; Unsteady flow; Non-steady characteristics; flow physics and modeling; Supersonic characteristics.
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 The Effects of Sweep and Bluntness on a Glancing Shock Wave Turbulent Boundary Layer Interaction written by N. R. Fomison and published by . This book was released on 1987 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation was conducted into the effects of leading edge sweep and bluntness on the flow characteristics of a glancing shock wave turbulent boundary layer interaction generated by a fin-on-plate configuration. A series of sharp swept fins (covering angles of sweep from 0 to 75 deg) and a series of blunt unswept fins (ranging in leading edge diameter from 0 to 25.4 mm) were tested at incidences of up to 30 deg at a Mach number of 2.4 and a freestream Reynolds number of 2.6 million/m. Observations of the mean flow were made using oil flow visualization, static pressure measurements, schlieren photography and vapour screen visualization techniques. In addition, some limited measurements of the unsteady static pressures beneath the interaction were taken. Flow field models are proposed to include the effects of sweep and bluntness and the governing parameters controlling the extent of the distributed flow and the pressure levels beneath the interaction are examined.
Download or read book Experimental Study of Three Dimensional Shock Wave Turbulent Boundary Layer Interaction Scaling of Sharp and Blunt Fin Induced Flowfields written by David S. Dolling and published by . This book was released on 1980 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study of three-dimensional (3-D) shock wave turbulent boundary layer interaction has been carried out. Interactions generated by fin models having sharp and hemi-cylindrically blunted leading edges have been studied. Tests have been made using incoming turbulent boundary layer varying in thickness in the ratio of about 4:1. Extensive surface property measurements have been made on the test surface on which the incoming boundary layer developed and on the fin itself. All of these tests were carried out at a nominal freestream Mach number of 3, a freestream unit Reynolds number of about 63 million per meter, and under approximately adiabatic wall conditions. The emphasis in the study reported on in this paper was on two main areas. First, to determine the key geometric and/or flow parameters controlling the overall scaling and characteristics of both blunt and sharp fin-induced interactions. Second, to identify the conditions under which both blunt and sharp fins induced interactions have the same local scale and characteristics. (Author).
Download or read book An Exploratory Study of a Three Dimensional Shock Wave Boundary Layer Interaction at Mach 3 written by B. Oskam and published by . This book was released on 1975 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: An exploratory experimental investigation has been carried out on the three dimensional flow fields caused by the interaction of oblique shock waves and a planar turbulent boundary layer. The study was performed at a free stream Mach number of 2.95, a Reynolds number per inch of 1.6 million and near adiabatic wall conditions. The interaction was studied on two experimental configurations having different initial boundary layer thicknesses (delta = approx. 0.13 and 0.55 inches). Both surface measurements as well as complete flow field surveys were performed. The main contributions of the present investigation are two experimentally derived flow field models for shock generator angles of 4 deg and 10 deg. Based upon both static pressure and surface flow patterns, as well as heat transfer data, the interaction region can be characterized as quasi-two-dimensional along the shock direction in the region studied. A critical examination of the occurrence of 'ordinary' flow separation and its character, as applied to the present problem, was carried out. It was concluded that McCabe's criterion, as used by the previous investigators, is not a sufficient condition to determine the onset of flow separation.
Download or read book Experimental Investigation of Crossing Shock Wave Turbulent Boundary Layer Bleed Interaction written by Hyun D. Kim and published by . This book was released on 1996 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Method for Analyzing the Interaction of an Oblique Shock Wave with a Boundary Layer written by William C. Rose and published by . This book was released on 1970 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Method for predicting interaction produced by externally generated, oblique shock wave impinging on laminar or turbulent boundary layers.
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 An Experimental Investigation of Unsteadiness in Swept Shock Wave turbulent Boundary Layer Interactions written by Triet Thuong Tran and published by . This book was released on 1987 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization of the Flowfield Near a Wrap Around Fin at Supersonic Speeds written by Carl P. Tilmann and published by . This book was released on 1998 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wall-mounted semi-cylindrical model fitted with a single wrap- around in (WAF) has been investigated numerically and experimentally, with the objective of characterizing the mean and turbulent flowfield near a WAF in a supersonic flowfield. Numerical and experimental results are used to determine the nature of the flowfield and quantify the effects of fin curvature on the character of the flow near WAFs. This research has been motivated by the need to identify possible sources of a high-speed rolling moment reversal observed in sub-scale flight tests. Detailed mean flow and turbulence measurements were obtained in the AFIT Mach 3 wind tunnel using conventional probes and cross-wire hot-film anemometry at a series of stations upstream of and aft of the fin shock/boundary layer interaction. Hot-film anemometry results showed the turbulence intensity and Reynolds shear stress in the fuselage boundary layer to be far greater on the concave side of the fin than on the convex side. Mean flow was also obtained in the AFIT Mach 5 wind tunnel using conventional pressure probes. Numerical results were also obtained at the test conditions employing the algebraic eddy viscosity model of Baldwin and Lomax. Correlation with experimental data suggests that the calculations have captured the flow physics involved in this complicated flowfield. The calculations, corroborated by experimental results, indicate that a vortex exists in the fin/body juncture region on the convex side of the fin. This feature is not captured by the oft- used inviscid methods, and can greatly influence the pressure loading on the fin near the root.
Download or read book Experimental Study of Shock wave Boundary layer Interaction in a Three dimensional Channel Flow written by R. Benay and published by . This book was released on 1985 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
