A Quiet Tunnel Investigation of Hypersonic Boundary-Layer Stability Over a Cooled, Flared Cone

A Quiet Tunnel Investigation of Hypersonic Boundary-Layer Stability Over a Cooled, Flared Cone
Author: National Aeronautics and Space Administration NASA
Publisher:
Total Pages: 30
Release: 2018-10-23
Genre:
ISBN: 9781729140024

A flared-cone model under adiabatic and cooled-wall conditions was placed in a calibrated, low-disturbance Mach 6 flow and the stability of the boundary layer was investigated using a prototype constant-voltage anemometer. The results were compared with linear-stability theory predictions and good agreement was found in the prediction of second-mode frequencies and growth. In addition, the same 'N = 10' criterion used to predict boundary-layer transition in subsonic, transonic, and supersonic flows under low freestream noise conditions was found to be applicable for the hypersonic flow regime as well. Under cooled-wall conditions, a unique set of spectral data was acquired that documents the linear, nonlinear, and breakdown regions associated with the transition of hypersonic flow under low-noise conditions. Blanchard, Alan E. and Selby, Gregory V. and Wilkinson, Stephen P. Langley Research Center NCC1-180...

Theories and Technologies of Hypervelocity Shock Tunnels

Theories and Technologies of Hypervelocity Shock Tunnels
Author: Zonglin Jiang
Publisher: Cambridge University Press
Total Pages: 316
Release: 2023-10-26
Genre: Technology & Engineering
ISBN: 1009035673

Introducing the state-of-the-art of hypervelocity shock tunnels, this complete reference features a variety of drivers and step-by-step introductions to their theories, physics, methods and testing. This book enables researchers and engineers in aerospace to design and improve wind tunnels that simulate flow qualities of real hypersonic flyers.

Hypersonic Boundary Layer Stability Experiments in a Quiet Wind Tunnel with Bluntness Effects

Hypersonic Boundary Layer Stability Experiments in a Quiet Wind Tunnel with Bluntness Effects
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
Total Pages: 232
Release: 2018-07-25
Genre:
ISBN: 9781724242556

Hypersonic boundary layer measurements over a flared cone were conducted in a Mach 6 quiet wind tunnel at a freestream unit Reynolds number of 2.82 million/ft. This Reynolds number provided laminar-to-transitional flow over the cone model in a low-disturbance environment. Four interchangeable nose-tips, including a sharp-tip, were tested. Point measurements with a single hot-wire using a novel constant voltage anemometer were used to measure the boundary layer disturbances. Surface temperature and schlieren measurements were also conducted to characterize the transitional state of the boundary layer and to identify instability modes. Results suggest that second mode disturbances were the most unstable and scaled with the boundary layer thickness. The second mode integrated growth rates compared well with linear stability theory in the linear stability regime. The second mode is responsible for transition onset despite the existence of a second mode subharmonic. The subharmonic disturbance wavelength also scales with the boundary layer thickness. Furthermore, the existence of higher harmonics of the fundamental suggests that nonlinear disturbances are not associated with 'high' free stream disturbance levels. Nose-tip radii greater than 2.7% of the base radius completely stabilized the second mode. Lachowicz, Jason T. and Chokani, Ndaona Langley Research Center NASA-CR-198272, NAS 1.26:198272 NCC1-183; RTOP-505-59-50-02...

IUTAM Laminar-Turbulent Transition

IUTAM Laminar-Turbulent Transition
Author: Spencer Sherwin
Publisher: Springer Nature
Total Pages: 809
Release: 2021-07-30
Genre: Computers
ISBN: 3030679020

This volume comprises the carefully revised papers of the 9th IUTAM Symposium on Laminar-Turbulent Transition, held at the Imperial College, London, UK, in September 2019. The papers focus on the leading research in understanding transition to turbulence, which is a challenging topic of fluid mechanics and arises in many modern technologies as well as in nature. The proceedings are of interest for researchers in fluid mechanics and industry who have to handle these types of problems, such as in the aeronautical sector.

Transition, Turbulence and Combustion

Transition, Turbulence and Combustion
Author: M.Y. Hussaini
Publisher: Springer Science & Business Media
Total Pages: 394
Release: 2012-12-06
Genre: Science
ISBN: 9401110328

These two volumes contain the proceedings of the Workshop on Transition, Turbulence and Combustion, sponsored by the Insti tute for Computer Applications in Science and Engineering (ICASE) and the NASA Langley Research Center (LaRC), during June 7 to July 2, 1993. Volume I contains the contributions from the transi tion research, and Volume II contains the contributions from both the turbulence and combustion research. This is the third workshop in the series on the subject. The first was held in 1989, the second in 1991, and their proceedings were published by Springer-Verlag under the titles "Instability and Transition" (edited by M. Y. Hussaini and R. G. Voigt) and "Instability, Transition and Turbulence" (edited by M. Y. Hussaini, A. Kumar and C. L. Streett) respectively. The objectives of these workshops are to expose the academic community to current technologically important issues of transition, turbulence and combustion, and to acquaint the academic commu nity with the unique combination of theoretical, computational and experimental capabilities at LaRC. It is hoped these will foster con tinued interactions, and accelerate progress in elucidating the funda mental phenomena of transition, turbulence and combustion. The research areas of interest in transition covered the full range of the subject: linear and nonlinear stability, direct and large-eddy simulation and phenomenological modeling of the transition zone.

Shock Wave-Boundary-Layer Interactions

Shock Wave-Boundary-Layer Interactions
Author: Holger Babinsky
Publisher: Cambridge University Press
Total Pages: 481
Release: 2011-09-12
Genre: Technology & Engineering
ISBN: 1139498649

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.