Flat-plate Boundary-layer Transition at Hypersonic Speeds

Flat-plate Boundary-layer Transition at Hypersonic Speeds PDF Author: R. E. Deem
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 204

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Flat-plate Boundary-layer Transition at Hypersonic Speeds

Flat-plate Boundary-layer Transition at Hypersonic Speeds PDF Author: R. E. Deem
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 204

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Transition Fixing for Hypersonic Flow

Transition Fixing for Hypersonic Flow PDF Author:
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 28

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Linear and Nonlinear Processes in Hypersonic Boundary Layer Transition to Turbulence

Linear and Nonlinear Processes in Hypersonic Boundary Layer Transition to Turbulence PDF Author: Kenneth Joseph Franko
Publisher:
ISBN:
Category :
Languages : en
Pages :

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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.

Boundary Layer Transition at Supersonic Speeds

Boundary Layer Transition at Supersonic Speeds PDF Author: E. R. Van Driest
Publisher:
ISBN:
Category : Aerodynamics, Supersonic
Languages : en
Pages : 108

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Experiments carried out in the 12-inch supersonic wind tunnel to investigate the effect of three dimensional roughness elements (spheres) on boundary-layer transition on a 10-degree (apex angle) cone without heat transfer are described. The local Mach number for these tests was 2.71. The data show clearly that the minimum (effective) size of trip required to bring transition to its lowest Reynolds number varies power of the distance from the apex of the cone to the trip. Use of available data at other Mach numbers indicates that the Mach number influence for effective tripping is taken into account by a simple expression. Some remarks concerning the roughness variation for transition on a blunt body are made. Finally, a general criterion is introduced which gives insight to the transition phenomenon and anticipates effects of external and internal disturbances, Mach number transfer.

A Brief Review of Some Mechanisms Causing Boundary Layer Transition at High Speeds

A Brief Review of Some Mechanisms Causing Boundary Layer Transition at High Speeds PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 16

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In-flight boundary-layer transition on a large flat plate at supersonic speeds

In-flight boundary-layer transition on a large flat plate at supersonic speeds PDF Author: D. W. Banks
Publisher:
ISBN:
Category :
Languages : en
Pages : 21

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Shock Wave-Boundary-Layer Interactions

Shock Wave-Boundary-Layer Interactions PDF 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.

Turbulence and Interactions

Turbulence and Interactions PDF Author: Michel Deville
Publisher: Springer Science & Business Media
ISBN: 3642002625
Category : Technology & Engineering
Languages : en
Pages : 166

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Book Description
Contains seven keynote lectures of the TI 2006 conference that was held in Porquerolles, May 29-June 2, 2006. This book offers a view on theory, experiments and numerical simulations in the field of turbulence.

Advances in Hypersonics

Advances in Hypersonics PDF Author: BALLMAN
Publisher: Springer Science & Business Media
ISBN: 1461203791
Category : Technology & Engineering
Languages : en
Pages : 448

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Book Description
These three volumes entitled Advances in Hypersonics contain the Proceedings of the Second and Third Joint US/Europe Short Course in Hypersonics which took place in Colorado Springs and Aachen. The Second Course was organized at the US Air Force Academy, USA in January 1989 and the Third Course at Aachen, Germany in October 1990. The main idea of these Courses was to present to chemists, com puter scientists, engineers, experimentalists, mathematicians, and physicists state of the art lectures in scientific and technical dis ciplines including mathematical modeling, computational methods, and experimental measurements necessary to define the aerothermo dynamic environments for space vehicles such as the US Orbiter or the European Hermes flying at hypersonic speeds. The subjects can be grouped into the following areas: Phys ical environments, configuration requirements, propulsion systems (including airbreathing systems), experimental methods for external and internal flow, theoretical and numerical methods. Since hyper sonic flight requires highly integrated systems, the Short Courses not only aimed to give in-depth analysis of hypersonic research and technology but also tried to broaden the view of attendees to give them the ability to understand the complex problem of hypersonic flight. Most of the participants in the Short Courses prepared a docu ment based on their presentation for reproduction in the three vol umes. Some authors spent considerable time and energy going well beyond their oral presentation to provide a quality assessment of the state of the art in their area of expertise as of 1989 and 1991.

Some Effects of Leading-edge Sweep on Boundary-layer Transition at Supersonic Speeds

Some Effects of Leading-edge Sweep on Boundary-layer Transition at Supersonic Speeds PDF Author: Gary T. Chapman
Publisher:
ISBN:
Category : Fluid mechanics
Languages : en
Pages : 38

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