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Author : M. Pino Martin
Publisher :
ISBN 13 :
Total Pages : 24 pages
Book Rating : 4.:/5 (395 download)
Download or read book DNS of Reacting Hypersonic Turbulent Boundary Layers written by M. Pino Martin and published by . This book was released on 1998 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Junji Huang
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (139 download)
Download or read book DNS of Hypersonic Turbulent Boundary Layers written by Junji Huang and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the physics of the pressure fluctuations induced by high-speed turbulent boundary layers (TBLs) is of major practical importance. The fluctuating pressure on aerodynamic surfaces of flight vehicles determines the vibrational loading of the vehicles and often leads to damaging effects as fatigue and flutter. The freestream pressure fluctuations radiated from the tunnel-wall TBLs are responsible for the genesis of freestream acoustic noise in conventional (i.e., noisy) supersonic and hypersonic wind tunnels. In this manuscript, wall and freestream pressure fluctuations induced by high-speed TBLs were characterized by direct numerical simulations (DNS). The DNS database covered a broad range of flow conditions (Mach number of $M_\infty = 2.5-14$, wall-to-recovery temperature ratio of $T_w/T_r = 0.18-1.0$, Reynolds number of $Re_\tau=450-1172$) and geometric configurations (flat plate, sharp circular cone, two dimensional channel, realistic wind-tunnel nozzle). The DNS overcame multiple experimental difficulties and provided access to wall and freestream pressure statistics that were difficulty to obtain otherwise, including the root-mean-square fluctuations and higher order moments (skewness and flatness) , probability density function , two-point correlation, convection speed, and coherence function. The study yielded useful insights into the physics of the boundary-layer-induced pressure field and provided critical assessment to reduced-order models such as the Corcos theory for modeling the wall pressure and the eddy-Mach-wave radiation theory for predicting the freestream acoustic pressure.
Author : M. Pino Martin
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (11 download)
Download or read book Prelimary DNS Database of Hypersonic Turbulent Boundary Layers written by M. Pino Martin and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Doyle Knight
Publisher :
ISBN 13 : 9780750350020
Total Pages : 0 pages
Book Rating : 4.3/5 (5 download)
Download or read book Hypersonic Shock Wave Turbulent Boundary Layers written by Doyle Knight and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hypersonic turbulent boundary layers are a fundamental phenomenon in high-speed flight. The interaction of shock waves with hypersonic turbulent boundary layers has a critical impact on vehicle aerothermodynamic loading including surface heat transfer, pressure and skin friction. This book provides a comprehensive exposition of hypersonic turbulent boundary layers, including the fundamental mathematical theory, structure of equilibrium boundary layers, and extensive surveys of Direct Numerical Simulation (DNS), Large Eddy Simulation (LES) and experiments. It also provides a roadmap for both future experiments and DNS and LES simulations. Descriptions of hypersonic ground test facilities is included as an appendix. As a research and reference text, this book would appeal to graduate students and researchers in hypersonics and could be the basis for professional training courses.
Author : Dennis M. Bushnell
Publisher :
ISBN 13 :
Total Pages : 44 pages
Book Rating : 4.:/5 (31 download)
Download or read book Comparison of Prediction Methods and Studies of Relaxation in Hypersonic Turbulent Nozzle-wall Boundary Layers written by Dennis M. Bushnell and published by . This book was released on 1969 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent boundary layer measurements on axisymmetric hypersonic nozzle walls.
Author : Xiaolin Zhong
Publisher :
ISBN 13 :
Total Pages : 12 pages
Book Rating : 4.:/5 (742 download)
Download or read book DNS of Hypersonic Boundary Layer Stability and Transition Using High-Order Nonuniform-Grid Schemes written by Xiaolin Zhong and published by . This book was released on 2001 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-order schemes are necessary for the DNS of stability and transition of hypersonic boundary layers because lower-order schemes do not have a sufficient accuracy level to compute small flow details. Currently, the main limiting factor in the application of high-order schemes is the numerical instability of high-order boundary closure schemes. In a previous AIAA paper (2001-0437), we presented a family of high-order nonuniform-grid finite-difference schemes with stable boundary closures for multi-dimensional flow simulations. In this paper, the high-order nominiform-grid schemes (up to 11th order) are applied to the numerical simulation of the receptivity of hypersonic boundary layers to freestream disturbances over a blunt leading edge. The stability and numerical accuracy of the new high-order nonuniform-grid schemes are evaluated for computing the nonlinear 2-D Navier-Stokes equations for hypersonic flow simulations.
Author : Michael Thomas Semper
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (871 download)
Download or read book Examining A Hypersonic Turbulent Boundary Layer at Low Reynolds Number written by Michael Thomas Semper and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of the current study was to answer several questions related to hypersonic, low Reynolds number, turbulent boundary layers, of which available data related to turbulence quantities is scarce. To that end, a unique research facility was created, instrumentation was developed to acquire data in the challenging low Reynolds number (low density) domain, and meaningful data was collected and analyzed. The low Reynolds number nature of the boundary layer (Re_theta = 3700) allows for tangible DNS computations/validations using the current geometry and conditions. The boundary layer examined in this experiment resembled other, higher Reynolds number boundary layers, but also exhibited its own unique characteristics. The Van Driest equivalent velocity scaling method was found to perform well, and the log layer of the law of the wall plot matched expected theory. Noticeably absent from the data was an overlap region between the two layers, which suggests a different profile for the velocity profiles at these low Reynolds number, hypersonic conditions. The low density effects near the wall may be having an effect on the turbulence that modifies this region in a manner not currently anticipated. The Crocco-Busemann relation was found to provide satisfactory results under its general assumptions. When compared to available data, the Morkovin scaled velocity fluctuations fell almost an order of magnitude short. Currently, it is not known if this deficit is due to inadequacies with the Strong Reynolds Analogy, or the Morkovin scaling parameters. The trips seem to promote uniformity across the span of the model, and the data seems to generally be in agreement across the spanwise stations. However, additional information is needed to determine if two-dimensional simulations are sufficient for these boundary layers. When the turbulent boundary layer power spectra is analyzed, the result is found to follow the traditional power law. This result verifies that even at low Reynolds numbers, the length scales still follow the behavior described by Kolmogorov. Moving downstream of the trips, the peak RMS disturbance value grows in amplitude until it reaches a critical value. After this point, the peak begins to decrease in amplitude, but the affected region spreads throughout the boundary layer. Once the influenced region covers a significant portion of the boundary layer, transition occurs. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/150983
Author : Kenneth Joseph Franko
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (758 download)
Download or read book Linear and Nonlinear Processes in Hypersonic Boundary Layer Transition to Turbulence written by Kenneth Joseph Franko and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The design of vehicles which travel at hypersonic speeds is strongly determined by drag characteristics and heat transfer. A portion of this drag and heating is due to the boundary layer where viscosity and thermal conductivity are most important. The level of drag and heating depends on whether the boundary layer is laminar or turbulent with the latter leading to higher levels of drag and heating. In addition, as high speed boundary layers transition from laminar to turbulent flow, an overshoot of the heat transfer beyond that of turbulent flow has been observed in experiments. In low disturbance environments, transition to turbulence follows the path of receptivity, linear growth, nonlinear interaction, and finally breakdown to turbulence. The linear growth of disturbances can be determined by linear stability theory. An analysis of the predicted growth rates and integrated growth of linear disturbances for hypersonic boundary layers including thermal and chemical non-equilibrium is undertaken. The sensitivity to different chemical assumptions, transport models and thermal boundary conditions is investigated. A disturbance energy norm is proposed and its corresponding balance equation is derived. This energy norm is then to determine the effect of different terms of the linear stability equations and to compute transient growth for hypersonic laminar boundary layers. DNS (Direct Numerical Simulation) is used to simulate the nonlinear breakdown to turbulence for a variety of transition scenarios for both zero pressure gradient and adverse pressure gradient high-speed flat plate boundary layers in order to investigate the mechanism for the overshoot of heat transfer in transitional hypersonic boundary layers. The initial disturbances are excited through suction and blowing at the wall and their frequencies are chosen based on linear stability theory. Different transition mechanisms are investigated including a pair of oblique waves and 2D and 3D instabilities at higher frequencies which are unique to high speed boundary layers. Oblique breakdown shows a clear overshoot in heat transfer and skin friction and leads to a fully turbulent boundary layer. The alternative scenarios also lead to transition but further downstream and without large overshoots in heat transfer. A detailed analysis of the transitional and turbulent regions is undertaken.
Author : John C. Adams
Publisher :
ISBN 13 :
Total Pages : 98 pages
Book Rating : 4.3/5 (91 download)
Download or read book Analysis of the Three-dimensional Compressible Turbulent Boundary Layer on a Sharp Cone at Incidence in Supersonic and Hypersonic Flow written by John C. Adams and published by . This book was released on 1972 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical approach toward numerical calculation of the three-dimensional turbulent boundary layer on a sharp cone at incidence under supersonic and hypersonic flow conditions is presented. The theoretical model is based on implicit finite-difference integration of the governing three-dimensional turbulent boundary-layer equations in conjunction with a three-dimensional scalar eddy-viscosity model of turbulence. Comparison is made of present theory with detailed experimental measurements of the three-dimensional turbulent boundary-layer structure (velocity and temperature profiles), the surface streamline direction (obtained via an oil-flow technique) and surface heat-transfer rate.
Author : María del Pino Martín Aguirre
Publisher :
ISBN 13 :
Total Pages : 216 pages
Book Rating : 4.:/5 (319 download)
Download or read book DNS and the LES Closure of Reacting Turbulence in Hypersonic Flows written by María del Pino Martín Aguirre and published by . This book was released on 1999 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : William H. Dorrance
Publisher : Courier Dover Publications
ISBN 13 : 048681288X
Total Pages : 353 pages
Book Rating : 4.4/5 (868 download)
Download or read book Viscous Hypersonic Flow written by William H. Dorrance and published by Courier Dover Publications. This book was released on 2017-07-18 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: Designed for advanced undergraduate and graduate courses in modern boundary-layer theory, this frequently cited work offers a self-contained treatment of theories for treating laminar and turbulent boundary layers of reacting gas mixtures. 1962 edition.
Author : J. S. Shang
Publisher :
ISBN 13 :
Total Pages : 52 pages
Book Rating : 4.3/5 (91 download)
Download or read book Parametric Study of Hypersonic Turbulent Boundary Layers with Heat Transfer written by J. S. Shang and published by . This book was released on 1974 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Alexander J. Smits
Publisher : Springer Science & Business Media
ISBN 13 : 0387263055
Total Pages : 418 pages
Book Rating : 4.3/5 (872 download)
Download or read book Turbulent Shear Layers in Supersonic Flow written by Alexander J. Smits and published by Springer Science & Business Media. This book was released on 2006-05-11 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: A good understanding of turbulent compressible flows is essential to the design and operation of high-speed vehicles. Such flows occur, for example, in the external flow over the surfaces of supersonic aircraft, and in the internal flow through the engines. Our ability to predict the aerodynamic lift, drag, propulsion and maneuverability of high-speed vehicles is crucially dependent on our knowledge of turbulent shear layers, and our understanding of their behavior in the presence of shock waves and regions of changing pressure. Turbulent Shear Layers in Supersonic Flow provides a comprehensive introduction to the field, and helps provide a basis for future work in this area. Wherever possible we use the available experimental work, and the results from numerical simulations to illustrate and develop a physical understanding of turbulent compressible flows.
Author : Marvin I. Kussoy
Publisher :
ISBN 13 :
Total Pages : 32 pages
Book Rating : 4.:/5 (317 download)
Download or read book Documentation of Two- and Three-dimensional Hypersonic Shock Wave/turbulent Boundary Layer Interaction Flows written by Marvin I. Kussoy and published by . This book was released on 1989 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Xiaolin Zhong
Publisher :
ISBN 13 :
Total Pages : 46 pages
Book Rating : 4.3/5 (91 download)
Download or read book Direct Numerical Simulation and Experimental Validation of Hypersonic Boundary-layer Receptivity and Instability written by Xiaolin Zhong and published by . This book was released on 2007 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research project is to compare our numerical simulation solutions with available experimental or theoretical results on hypersonic boundary layer receptivity and stability; and to conduct extensive DNS studies on the flow mechanisms of hypersonic boundary layer receptivity and stability. During the three-year period, we have conducted extensive DNS studies on the receptivity of hypersonic boundary layer flows over a sharp wedge, a flat plate, a blunt cone, and the FRESH aeroshell. DNS studies are compared with Stetson's 1984 stability experiment on Mach 7.99 flow over a blunt cone, and Maslov's leading-edge receptivity experiment on Mach 5.92 flow over a flat plate. Our numerical studies have been validated to be of high accuracy and led to further understanding of hypersonic boundary layer receptivity mechanism. Such understanding can lead to better tools for the prediction and control of high-speed boundary layer transition.
Author : Arnold Polak
Publisher :
ISBN 13 :
Total Pages : 56 pages
Book Rating : 4.3/5 (91 download)
Download or read book Hypersonic-turbulent Boundary-layer Separation Over a Cone-cylinder-flare Configuration written by Arnold Polak and published by . This book was released on 1969 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of a study of hypersonic-turbulent boundary-layer separation over axisymmetric bodies are presented. Pressure, heat-transfer and flow visualization data were obtained for a cone-cylinder-flare configuration. The experimental data were correlated with a theoretical prediction. (Author).
Author : PILBUM KIM
Publisher :
ISBN 13 :
Total Pages : 112 pages
Book Rating : 4.:/5 (17 download)
Download or read book Non-equilibrium Effects on Hypersonic Turbulent Boundary Layers written by PILBUM KIM and published by . This book was released on 2016 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding non-equilibrium effects of hypersonic turbulent boundary layers is essential in order to build cost efficient and reliable hypersonic vehicles. It is well known that non-equilibrium effects on the boundary layers are notable, but our understanding of the effects are limited. The overall goal of this study is to improve the understanding of non-equilibrium effects on hypersonic turbulent boundary layers. A new code has been developed for direct numerical simulations of spatially developing hypersonic turbulent boundary layers over a flat plate with finite-rate reactions. A fifth-order hybrid weighted essentially non-oscillatory scheme with a low dissipation finite-difference scheme is utilized in order to capture stiff gradients while resolving small motions in turbulent boundary layers. The code has been validated by qualitative and quantitative comparisons of two different simulations of a non-equilibrium flow and a spatially developing turbulent boundary layer. With the validated code, direct numerical simulations of four different hypersonic turbulent boundary layers, perfect gas and non-equilibrium flows of pure oxygen and nitrogen, have been performed. In order to rule out uncertainties in comparisons, the same inlet conditions are imposed for each species, and then mean and turbulence statistics as well as near-wall turbulence structures are compared at a downstream location. Based on those comparisons, it is shown that there is no direct energy exchanges between internal and turbulent kinetic energies due to thermal and chemical non-equilibrium processes in the flow field. Instead, these non-equilibria affect turbulent boundary layers by changing the temperature without changing the main characteristics of near-wall turbulence structures. This change in the temperature induces the changes in the density and viscosity and the mean flow fields are then adjusted to satisfy the conservation laws. The perturbation fields are modified according to the adjusted mean field and the conservation laws. From this, it can be concluded that Morkovin's hypothesis is still valid with thermal and chemical non-equilibrium, and the effects of non-equilibrium can be compensated by taking the variations of mean density and viscosity into account. In the present study, it is shown that a semi-local scale is a proper scale that can account for the non-equilibrium effects.
