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Short‐length instabilities, breakdown and initial value problems in dynamic stall
Author(s) -
Ryzhov O. S.,
Smith F. T.
Publication year - 1984
Publication title -
mathematika
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.955
H-Index - 29
eISSN - 2041-7942
pISSN - 0025-5793
DOI - 10.1112/s0025579300012407
Subject(s) - stall (fluid mechanics) , airfoil , mechanics , instability , choked flow , supersonic speed , angle of attack , mathematics , nonlinear system , boundary value problem , physics , classical mechanics , aerodynamics , mathematical analysis , quantum mechanics
Summary A recent paper [1] indicates that the beginnings of dynamic stall, near an aerofoil's leading edge, for instance, can be regarded as the finite‐time nonlinear breakdown of a boundary layer subjected to an angle of attack above the critical value for the existence of a steady solution. The present theoretical study shows that the same non‐linear breakdown can occur even in the below ‐critical regime. This happens particularly when reversed flow is present since short wavelength disturbances are then unstable and accumulate, for certain confined initial conditions, to force the finite‐time collapse. A number of marginal cases with forward or reversed, subsonic or supersonic, oncoming motion are also noted and shed extra light on the instability and subsequent breakdown.