Periodic vortex shedding in the supersonic wake of a planar plate

Vortex sheets in the wake have been mainly studied in incompressible flows and in the transonic region. Heinemann et al. (1976) have shown that for the subsonic region the Strouhal number is nearly independent of the Mach number. Motallebi and Norbury (1981) have observed an increase in the Strouhal number in transonic supersonic flow at Mach numbers up to 1.25. The present investigation is concerned with an extension of the studies of vortex shedding to higher supersonic Mach numbers, taking into account questions regarding the possibility of a generation of stable von Karman vortex paths in the considered Mach number range. It is found that the vortex sheet observed in a supersonic wake behind a rough plate is only stable and reproducible in cases involving a certain surface roughness and certain aspects of trailing edge geometry

The Molonglo Southern 4 Jy sample (MS4). II. ATCA imaging and optical identification

Of the 228 sources in the Molonglo Southern 4 Jy Sample (MS4), the 133 with angular sizes < 35 arcsec have been imaged at 5 GHz at 2-4 arcsec resolution with the Australia Telescope Compact Array. More than 90% of the sample has been reliably optically identified, either on the plates of the UK Schmidt Southern Sky Survey or on R-band CCD images made with the Anglo-Australian Telescope. A subsample of 137 sources, the SMS4, defined to be a close southern equivalent of the northern 3CRR sample, was found to have global properties mostly consistent with the northern sample. Linear sizes of MS4 galaxies and quasars were found to be consistent with galaxy-quasar unification models of orientation and evolution.Comment: 102 pages; 6 figures in 21 Postscript files. To appear in Astronomical Journal. For higher-resolution versions of some figures, see http://www.physics.usyd.edu.au/astrop/rwh/ms4