Author: Will J. Stoffers
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 52
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Book Description
This paper presents a low order simulation of a hypersonic shock tunnel experiment at the Calspan-University at Buffalo Research Center (CUBRC). In this experiment, a relatively low enthalpy flow is passed over a double cone geometry at a speed near Mach 12. Empirical data is taken and a higher order simulation of the experiment is also used for comparison. The present study compares the low fidelity data (first order spatial reconstruction) against the empirical and higher fidelity data (second order reconstruction) for this flow. A large difference in separation zone length is evident between the high and low order simulations when pressure and heat transfer are plotted. This confirms the dissipative nature of low order numerical schemes. An evaluation of chemistry models is made as well, comparing the Park model with Kang & Dunn's. Little difference is observed between the low order Park results and the low order Kang & Dunn data. The Kang & Dunn model is chosen because it requires fewer computational resources.
Author: Y.P. Golovachov
Publisher: Springer Science & Business Media
ISBN: 9401584907
Category : Mathematics
Languages : en
Pages : 359
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Book Description
The book is concerned with mathematical modelling of supersonic and hyper sonic flows about bodies. Permanent interest in this topic is stimulated, first of all, by aviation and aerospace engineering. The designing of aircraft and space vehicles requires a more precise prediction of the aerodynamic and heat transfer characteristics. Together with broadening of the flight condition range, this makes it necessary to take into account a number of gas dynamic and physical effects caused by rarefaction, viscous-inviscid interaction, separation, various physical and chemical processes induced by gas heating in the intensive bow shock wave. The flow field around a body moving at supersonic speed can be divided into three parts, namely, shock layer, near wake including base flow, and far wake. The shock layer flow is bounded by the bow shock wave and the front and lat eral parts of the body surface. A conventional approach to calculation of shock layer flows consists in a successive solution of the inviscid gas and boundary layer equations. When the afore-mentioned effects become important, implementation of these models meets difficulties or even becomes impossible. In this case, one has to use a more general approach based on the viscous shock layer concept.
Author: Christopher E. Glass
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 28
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Book Description
CFD numerical simulations of low-density shock-wave interactions for an incident shock impinging on a cylinder have been performed. Flow-field density gradient and surface pressure and heating define the type of interference pattern and corresponding perturbations. The maximum pressure and heat transfer level and location of various interaction types are presented. A time-accurate solution of the Type IV interference is employed to demonstrate the establishment and the steadiness of the low-density flow interaction.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 105
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Book Description
There has been increasing interest in developing numerical methods and accurate physical models for solving computational fluid dynamics (CFD) problems of hypersonic continuum and rarefied flows. In this work, we establish a framework for validating numerical methods and physical models employed in popular CFD codes. The first main objective of this work is to assess the ability of current state-of-the-art methods to simulate challenging hypersonic flow problems by comparing to well characterized experiments. The second main objective is to provide benchmark numerical solutions to hypersonic double-cone laminar flows that can be used as code validation cases.
Author: Holger Babinsky
Publisher: Cambridge University Press
ISBN: 1139498649
Category : Technology & Engineering
Languages : en
Pages : 481
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Book Description
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.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 33
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Book Description
The goal of this research is to study the laminar turbulent transition and other transient flow phenomena of 3-D chemically reacting hypersonic boundary layers by direct numerical simulation (DNS) and by linear stability analysis. The research in the report period was focused on developing new numerical methods for such studies and studying several fundamental transient hypersonic flow phenomena. First, several new efficient and high-order accurate numerical methods for DNS of 3-D hypersonic reacting boundary layers and for computing unsteady hypersonic flows with complex shock interactions were developed. These new methods were developed in order to overcome difficulties associated with the direct numerical simulation of hypersonic flows. Second, several studies on the stability phenomena of hypersonic boundary layers over blunt leading edges both by direct numerical simulation and by linear stability analyses were performed. Also completed were extensive numerical studies on real gas effects on a steady shock/boundary layer interaction and a self-sustained unsteady shock-shock interference heating flows. Third, the effects of using Burnett equations for rarefied hypersonic flow computations were investigated. With the completion of the bulk of work on the development of new numerical methods for complex hypersonic flow simulation, the DNS studies are currently being extended to 3-D hypersonic boundary layer transition over elliptic cross section cones.
Author: Datta V. Gaitonde
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 64
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Book Description
The interaction of an impinging shock with the bow-shock generated by a blunt geometry is examined numerically for hypersonic (Mach 8, perfect gas) flows with modified Steger-Warming flux-split scheme. The modifications are designed to reduce numerical dissipation in the boundary layer thus improving the resolution and accuracy of the resulting algorithm. The full 2-D Navier- Stokes equations are solved in finite-volume formulation with central differencing for viscous terms and residual driven line Gauss-Seidel relaxation for time advancement. Grid resolution studies are performed. For a Type IV interaction, comparison with surface pressure and heat-transfer rates display good overall agreement with experimental values. For a Type III+ interaction, a detailed comparison is made with experimental surface quantities and a computation with Van Leer's flux-splitting algorithm. The peak amplification of pressure is modestly overpredicted with the current algorithm. The computed peak heat transfer is comparable to that obtained in previous research with Van Leer's splitting, although anomalous behavior is observed in the vicinity of the stagnation point. This behavior may be eliminated with appropriate corrections.
Author: John Webster Ellinwood
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 50
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Book Description
Stewartson's theory for axisymmetric hypersonic flow of a model gas with strong viscous interaction and strong shock wave is extended to power-law viscosity variation, nonunit Prandtl number, and body shapes other than power laws. For power-law bodies, the generalized theory is obtained in closed form without recourse to numerical integration. In addition, numerical computations are presented for axisymmetric flow over a three-quarter power-law body with strong shock wave and viscous interactions that range from weak to strong. (Author).
Author: M. Pino Martin
Publisher:
ISBN:
Category : Laminar boundary layer
Languages : en
Pages : 34
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Book Description
Shockwave and turbulent boundary layer interactions produce intense localized pressure loads and heating rates that can have a dramatic influence on the drag and heating experienced by a high-speed vehicle, and can significantly impact fuel mixing and combustion in propulsion systems. The lack of standardized and traceable databases prevents the calibration of computational fluid dynamic models to accurately represent these critical flow phenomena. In this work we accomplished the development and validation against experiments at the same flow and boundary conditions of direct numerical simulations of shock and turbulent boundary layer interactions. We pioneered the development of a unique numerical capability that allows the accurate and detailed three-dimensional turbulence data at a reasonable turn-around time. In turn, parametric studies of fundamental flow physics are feasible, for the first time. By accurate, it is meant that the numerical uncertainty is within the experimental error.
Author: Jiri Blazek
Publisher: Elsevier
ISBN: 0080529674
Category : Science
Languages : en
Pages : 491
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Book Description
Computational Fluid Dynamics (CFD) is an important design tool in engineering and also a substantial research tool in various physical sciences as well as in biology. The objective of this book is to provide university students with a solid foundation for understanding the numerical methods employed in today's CFD and to familiarise them with modern CFD codes by hands-on experience. It is also intended for engineers and scientists starting to work in the field of CFD or for those who apply CFD codes. Due to the detailed index, the text can serve as a reference handbook too. Each chapter includes an extensive bibliography, which provides an excellent basis for further studies.
