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Asymptotic methods for internal transonic flowsFor many internal transonic flows of practical interest, some of the relevant nondimensional parameters typically are small enough that a perturbation scheme can be expected to give a useful level of numerical accuracy. A variety of steady and unsteady transonic channel and cascade flows is studied with the help of systematic perturbation methods which take advantage of this fact. Asymptotic representations are constructed for small changes in channel cross-section area, small flow deflection angles, small differences between the flow velocity and the sound speed, small amplitudes of imposed oscillations, and small reduced frequencies. Inside a channel the flow is nearly one-dimensional except in thin regions immediately downstream of a shock wave, at the channel entrance and exit, and near the channel throat. A study of two-dimensional cascade flow is extended to include a description of three-dimensional compressor-rotor flow which leads to analytical results except in thin edge regions which require numerical solution. For unsteady flow the qualitative nature of the shock-wave motion in a channel depends strongly on the orders of magnitude of the frequency and amplitude of impressed wall oscillations or fluctuations in back pressure. One example of supersonic flow is considered, for a channel with length large compared to its width, including the effect of separation bubbles and the possibility of self-sustained oscillations. The effect of viscosity on a weak shock wave in a channel is discussed.
Document ID
19890011566
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Adamson, T. C., Jr. (Michigan Univ. Ann Arbor, MI, United States)
Messiter, A. F. (Michigan Univ. Ann Arbor, MI, United States)
Date Acquired
September 5, 2013
Publication Date
March 1, 1989
Publication Information
Publication: NASA, Langley Research Center, Transonic Symposium: Theory, Application, and Experiment, Volume 1, Part 1
Subject Category
Aerodynamics
Accession Number
89N20937
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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