Accession Number : AD0013229


Title :   A STUDY OF PHYSICS OF PERTURBATION OF SUBSONIC CIRCULAR JETS


Corporate Author : COLUMBIA UNIV NEW YORK ACOUSTICS LAB


Personal Author(s) : Wegel, R L


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/013229.pdf


Report Date : 29 May 1953


Pagination or Media Count : 36


Abstract : Small departures from steady flow of a subsonic circular jet in an incompressible inviscid fluid are described in terms of a series of wave mode functions. the potential of a typical component mode (representing the velocity potential in cylindrical coordinates along the jet axis) is expressed in terms of a modified Bessel function and Hs, a unit amplitude periodic function of 0. On the jet surface, Hs represents a (1) series of longitudinal ridges modulated sinusoidally along it and moving downstream and/or (2) spiral ridges. The instability of columnar flow is described by the growth in amplitude along the jet. The stabilizing influence of viscous forces in real jets results in disintegration into terminal turbulence at a much slower rate than that indicated by idealized theory. Experimental data are necessary to obtain a more definitive rationalization of this phenomenon in real jets. Theoretical and experimental wave-transmission techniques are shown to be applicable.


Descriptors :   *EDDIES(FLUID MECHANICS) , RIDGES , EXPERIMENTAL DATA , TURBULENCE , CYLINDRICAL BODIES , SUBSONIC CHARACTERISTICS , WAVE FUNCTIONS , AMPLITUDE , INVISCID FLOW , CIRCULAR , INCOMPRESSIBILITY , STEADY FLOW , BESSEL FUNCTIONS , VELOCITY , STABILITY


Subject Categories : Fluid Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE