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Coupled Radiation Gasdynamic Solution Method For Hypersonic Shock Layers In Thermochemical Nonequilibrium
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Book Synopsis Coupled Radiation-gasdynamic Solution Method for Hypersonic Shock Layers in Thermochemical Nonequilibrium by : Christopher L. Martin
Download or read book Coupled Radiation-gasdynamic Solution Method for Hypersonic Shock Layers in Thermochemical Nonequilibrium written by Christopher L. Martin and published by . This book was released on 2011 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Predicting Radiative Heat Transfer in Thermochemical Nonequilibrium Flow Fields by : Lin Hartung Chambers
Download or read book Predicting Radiative Heat Transfer in Thermochemical Nonequilibrium Flow Fields written by Lin Hartung Chambers and published by . This book was released on 1994 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The theory for radiation emission, absorption, and transfer in a thermochemical nonequilibrium flow is presented. The expression developed reduce correctly to the limit at equilibrium. To implement the theory in a practical computer code, some approximations are used, particularly the smearing of molecular radiation. Details of these approximations are presented and helpful information is included concerning the use of the computer code. This user's manual should benefit both occasional users of the Langley Optimized RAdiative Nonequilibrium (LORAN) code and those who wish to use it to experiment with improved models or properties.
Book Synopsis A Thin-shock-layer Solution for Nonequilibrium, Inviscid Hypersonic Flows in Earth, Martian, and Venusian Atmospheres by : William L. Gose
Download or read book A Thin-shock-layer Solution for Nonequilibrium, Inviscid Hypersonic Flows in Earth, Martian, and Venusian Atmospheres written by William L. Gose and published by . This book was released on 1971 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: An approximate inverse solution is presented for the nonequilibrium flow in the inviscid shock layer about a vehicle in hypersonic flight. The method is based upon a thin-shock-layer approximation and has the advantage of being applicable to both subsonic and supersonic regions of the shock layer. The relative simplicity of the method makes it ideally suited for programming on a digital computer with a significant reduction in storage capacity and computing time required by other more exact methods. Comparison of nonequilibrium solutions for an air mixture obtained by the present method is made with solutions obtained by two other methods. Additional cases are presented for entry of spherical nose cones into representative Venusian and Martian atmospheres. A digital computer program written in FORTRAN language is presented that permits an arbitrary gas mixture to be employed in the solution. The effects of vibration, dissociation, recombination, electronic excitation, and ionization are included in the program.
Book Synopsis Supersonic Unstable Modes in Hypersonic Boundary Layers with Thermochemical Nonequilibrium Effects by : Carleton Knisely
Download or read book Supersonic Unstable Modes in Hypersonic Boundary Layers with Thermochemical Nonequilibrium Effects written by Carleton Knisely and published by . This book was released on 2018 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mack's second mode has been known to be the dominant disturbance leading to transition to turbulence in traditional hypersonic boundary layer flows at zero angle of attack. Physically, the second mode exists due to trapped acoustic waves within the boundary layer. The second mode has been widely studied and the conditions that stabilize or amplify the second mode are well documented. Predicting the second mode amplification is the basis of contemporary transition prediction techniques such as the eN method. There has been a renewed interest in studying hypersonic boundary layer stability in high-enthalpy flows with highly-cooled walls due to its applicability to experiments and some real flight conditions. One physical phenomenon that occurs in these flows is the creation of a supersonic mode, which is associated with an unstable mode F1 synchronizing with the slow acoustic spectrum. This causes the disturbance to travel upstream supersonically relative to the mean flow outside the boundary layer and radiate sound away from the boundary layer. The supersonic mode has been known to exist for decades, but has until recently been deemed negligible in comparison to the second mode. However, a resurgence in interest in the supersonic mode has shown the supersonic mode to exist in unexpected conditions with considerable peak growth rates compared to the second mode. Namely, recent research in the field has shown the supersonic mode in hot-wall flows, upending the notion that it is an artifact of highly-cooled walls. Additionally, a dominant supersonic mode with significantly larger growth rate than the second mode has been found on very blunt cones. Therefore, because the supersonic mode has not been systematically investigated, the mechanism of its creation and the conditions under which it exists are not yet clear. The objective of this work is to systematically investigate the supersonic mode using numerical and theoretical tools to simulate hypersonic flow over blunt cones. Specifically, this work aims to (1) Determine the characteristics of the supersonic mode and under what conditions it exists, (2) Explore the effectiveness of Linear Stability Theory (LST) on predicting the supersonic mode, and (3) Examine the impact of the supersonic mode on transition to turbulence under realistic flight or experimental conditions. This work explores the supersonic mode on a 1 mm nose radius cone in various free stream flow configurations with a 5-species, two-temperature nonequilibrium gas model for air. A combined approach of Direct Numerical Simulation (DNS) and Linear Stability Theory (LST) are used to numerically investigate the supersonic mode. New LST equations with linearized Rankine-Hugoniot shock relation boundary conditions are derived and verified. In addition, a theoretical schematic has been developed to aid future experimentalists and those performing DNS in visualizing the supersonic mode. Mach numbers of 5 and 10 are considered with wall-temperature-to-free-stream-temperature ratios (Tw/T ) between 0.2 and 1.43. Additionally, the impact of thermochemical nonequilibrium on the supersonic mode is assessed. Both LST and DNS results have confirmed the existence of the supersonic mode on a Mach 5 axisymmetric cold-wall (Tw/T = 0.2) cone. On a warmer wall (Tw/T = 0.667) under the same free stream conditions, LST indicated the supersonic mode was stabilized, although some weak sound radiation was still apparent in DNS. For the Mach 10 case, LST predicted a stable supersonic mode for both wall temperature cases (Tw/T = 1.43, Tw/T = 0.43), however a prominent supersonic mode was observed in DNS. The supersonic mode was determined to be excited via a modal interaction that is ignored in LST due to the independent mode assumption. Furthermore, the supersonic mode in the Mach 10 case with Tw/T = 0.43 exhibited a stronger peak growth rate for the supersonic mode compared to Mack's traditional second mode. These findings illustrate the need for combined LST and DNS studies of the supersonic mode. Overall, this study has determined that the supersonic mode is destabilized by largely the same factors as Mack's second mode. Namely, wall cooling is destabilizing, increasing Mach number/stagnation enthalpy is destabilizing, and vibrational nonequilibrium is stabilizing. The impact of chemical nonequilibrium is hypothesized to be slightly destabilizing, although was not able to be confirmed with the cases explored here. Based on the results presented here, transition prediction analyses relying on LST, such as the eN method, should be used with caution when applied to the supersonic mode, as it has been shown that LST may not fully capture the mechanism of the supersonic mode's creation.
Book Synopsis Ablation and Radiation Coupled Viscous Hypersonic Shock Layers, Volume 1 by :
Download or read book Ablation and Radiation Coupled Viscous Hypersonic Shock Layers, Volume 1 written by and published by . This book was released on 1971 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Assessment of Nonequilibrium Radiation Computation Methods for Hypersonic Flows by :
Download or read book Assessment of Nonequilibrium Radiation Computation Methods for Hypersonic Flows written by and published by . This book was released on 1993 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ablation and Radiation Coupled Viscous Hypersonic Shock Layers, Volume 2 by :
Download or read book Ablation and Radiation Coupled Viscous Hypersonic Shock Layers, Volume 2 written by and published by . This book was released on 1971 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Hypersonic Viscous Shock Layer of Nonequilibrium Dissociating Gas by : Paul Myung-Ha Chung
Download or read book Hypersonic Viscous Shock Layer of Nonequilibrium Dissociating Gas written by Paul Myung-Ha Chung and published by . This book was released on 1961 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Radiation-coupled Chemical Nonequilibrium Normal Shock Waves by : Martin Philip Sherman
Download or read book Radiation-coupled Chemical Nonequilibrium Normal Shock Waves written by Martin Philip Sherman and published by . This book was released on 1966 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: The problem of a normal shock wave in air or other gas with complex chemistry and coupled radiation is considered. Molecular transport properties are neglected and the gas mixture is assumed in translational, rotation, vibrational and electronic equilibrium with the local temperature. Only continuum radiation is included. Solutions are presented for strong shock waves in air, where air is assumed to consist of eleven species, N2, O2, O, NO, NO+, N+, O, N2+, O2+ and electrons. The usal methods of integrating the stiff ordinary differential equations of chemical nonequilibrium flow are limited to very small step sizes. Methods are developed which permit vastly larger step sizes. Solutions are obtained for the optically thin case, and with absorption of radiation behind the shock front. The spectrum is broken into regions inside of which the absorption cross sections are only a function of temperature. (Author).
Book Synopsis Hypersonic and High Temperature Gas Dynamics by : John David Anderson
Download or read book Hypersonic and High Temperature Gas Dynamics written by John David Anderson and published by AIAA. This book was released on 1989 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a self-contained text for those students and readers interested in learning hypersonic flow and high-temperature gas dynamics. It assumes no prior familiarity with either subject on the part of the reader. If you have never studied hypersonic and/or high-temperature gas dynamics before, and if you have never worked extensively in the area, then this book is for you. On the other hand, if you have worked and/or are working in these areas, and you want a cohesive presentation of the fundamentals, a development of important theory and techniques, a discussion of the salient results with emphasis on the physical aspects, and a presentation of modern thinking in these areas, then this book is also for you. In other words, this book is designed for two roles: 1) as an effective classroom text that can be used with ease by the instructor, and understood with ease by the student; and 2) as a viable, professional working tool for engineers, scientists, and managers who have any contact in their jobs with hypersonic and/or high-temperature flow.
Book Synopsis Effects of Thermochemical Nonequilibrium on Hypersonic Boundary-Layer Instability in the Presence of Surface Ablation Or Isolated Two-Dimensional Roughness by : Clifton Mortensen
Download or read book Effects of Thermochemical Nonequilibrium on Hypersonic Boundary-Layer Instability in the Presence of Surface Ablation Or Isolated Two-Dimensional Roughness written by Clifton Mortensen and published by . This book was released on 2015 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current understanding of the effects of thermochemical nonequilibrium on hypersonic boundary-layer instability still contains uncertainties, and there has been little research into the effects of surface ablation, or two-dimensional roughness, on hypersonic boundary-layer instability. The objective of this work is to study the effects of thermochemical nonequilibrium on hypersonic boundary-layer instability. More specifically, two separate nonequilibrium flow configurations are studied: 1) flows with graphite surface ablation, and 2) flows with isolated two-dimensional surface roughness. These two flow types are studied numerically and theoretically, using direct numerical simulation and linear stability theory, respectively. To study surface ablation, a new high-order shock-fitting method with thermochemical nonequilibrium and finite-rate chemistry boundary conditions for graphite ablation is developed and validated. The method is suitable for direct numerical simulation of boundary-layer transition in a hypersonic real-gas flow with graphite ablation. The new method is validated by comparison with three computational data sets and one set of experimental data. Also, a thermochemical nonequilibrium linear stability theory solver with a gas phase model that includes multiple carbon species, as well as a linearized surface graphite ablation model, is developed and validated. It is validated with previously published linear stability analysis and direct numerical simulation results. A high-order method for discretizing the linear stability equations is used which can easily include high-order boundary conditions. The developed codes are then used to study hypersonic boundary-layer instability for a 7 deg half angle blunt cone at Mach 15.99 and the Reentry F experiment at 100~kft. Multiple simulations are run with the same geometry and freestream conditions to help separate real gas, blowing, and carbon species effects on hypersonic boundary-layer instability. For the case at Mach 15.99, a directly simulated 525~kHz second-mode wave was found to be significantly unstable for the real-gas simulation, while in the ideal-gas simulations, no significant flow instability is seen. An N factor comparison also shows that real-gas effects significantly destabilize the flow when compared to an ideal gas. Blowing is destabilizing for the real gas simulation and has a negligible effect for the ideal gas simulation due to the different locations of instability onset. Notably, carbon species resulting from ablation are shown to slightly stabilize the flow for both cases. For the Reentry F flow conditions, inclusion of the ablating nose cone was shown to increase the region of second mode growth near the nose cone. Away from the nose cone, the second mode was relatively unaffected. Experimental and numerical results have shown that two-dimensional surface roughness can stabilize a hypersonic boundary layer dominated by second-mode instability. It is sought to understand how this physical phenomenon extends from an airflow under a perfect gas assumption to that of a flow in thermochemical nonequilibrium. To these ends, a new high-order shock-fitting method that includes thermochemical nonequilibrium and a cut-cell method, to handle complex geometries unsuitable for structured body-fitted grids, is presented. The new method is designed specifically for direct numerical simulation of hypersonic boundary-layer transition in a hypersonic real-gas flow with arbitrary shaped surface roughness. The new method is validated and shown to perform comparably to a high-order method with a body-fitted grid. For a Mach 10 flow over a flat plate, a two-dimensional roughness element was found to stabilize the second mode when placed downstream of the synchronization location. This result is consistent with previous results for perfect-gas flows. For a Mach 15 flow over a flat plate, a two-dimensional surface roughness element stabilizes the second-mode instability more effectively in a thermochemical nonequilibrium flow, than in a corresponding perfect gas flow.
Book Synopsis Coupling of Gas-surface Interaction and Material Response in Hypersonic Ablation by : Guangwei Liu
Download or read book Coupling of Gas-surface Interaction and Material Response in Hypersonic Ablation written by Guangwei Liu and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Hypersonic flight has seen a considerable resurgence of interest over the past two decades. Several unique physical phenomena occur in this ultra-high-speed regime, one of them being a bow shock appearing in front of the vehicle. There is a rapid increase in temperature across this thin shock layer that imposes high heat loads on the windward surface of the aircraft. Thermal Protection Systems are therefore crucial to prevent heat damage. Such systems consist of a layer of insulation covering the craft's surface. Experimental trials on Thermal Protection Systems are complex, expensive, and difficult to repeat because of the hypersonic flow conditions and shape of the vehicles. CFD can complement experiments by providing reliable predictions for a wide range of operating conditions and complex geometries. It is thus the most viable approach at the design stages.The present work extends the capabilities of the HALO3D (High Altitude Low Orbit, 3D) hypersonic flow simulation software to predict the surface ablation behavior along the re-entry trajectory of a vehicle. A loosely coupled model is established to consider the thermochemical non-equilibrium of the flow field and heat transfer inside the solid protection layer. The gasdynamic equations of chemical-thermal non-equilibrium air and the heat conduction in the solid material are solved separately and loosely coupled to increase computational efficiency. The surface chemistry is solved involving the gaseous reactant from the Thermal Protection Systems as well as chemical non-equilibrium conditions. The gas-surface interactions are simulated with a quasi-steady assumption. By contrast, the material response is solved transiently and coupled with gas-surface interaction results through interface boundary conditions. The computational grids of both fluid and solid domains are updated at every trajectory point.The surface chemistry solver is verified and validated with various freestream temperatures and pressures. The coupling between gas-surface interaction and material response is verified through one-dimensional heat transfer. The loosely coupled ablation approach is first validated for a rocket engine blast pipe with given surface regression rates and temperature-dependent material properties. The capabilities of the proposed coupling methodology are then demonstrated for a scenario of hypersonic flow over a half-cylinder"--
Book Synopsis Journal of Thermophysics and Heat Transfer by :
Download or read book Journal of Thermophysics and Heat Transfer written by and published by . This book was released on 2007 with total page 868 pages. Available in PDF, EPUB and Kindle. Book excerpt: This journal is devoted to the advancement of the science and technology of thermophysics and heat transfer through the dissemination of original research papers disclosing new technical knowledge and exploratory developments and applications based on new knowledge. It publishes papers that deal with the properties and mechanisms involved in thermal energy transfer and storage in gases, liquids, and solids or combinations thereof. These studies include conductive, convective, and radiative modes alone or in combination and the effects of the environment.
Book Synopsis International Aerospace Abstracts by :
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1997 with total page 940 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1993 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ablation and Radiation Coupled Viscous Hypersonic Shock Layers by : Carl D. Engel
Download or read book Ablation and Radiation Coupled Viscous Hypersonic Shock Layers written by Carl D. Engel and published by . This book was released on 1971 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:
