The interactions between upstream-propagating guided jet waves and shear-layer instability near the nozzle of subsonic nearly ideally expanded supersonic, isothermal free jets are investigated for at Mach numbers 0.50 2 with fully laminar exit boundary layers different thicknesses. velocity spectra in shear downstream exhibit strong narrow peaks first azimuthal modes, associated growing Kelvin–...

A new tropopause definition involving a flow-dependent blending of the traditional thermal tropopause with one based on potential vorticity has been developed and applied to the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalyses (ERA), ERA-40 and ERA-Interim. Global and regional trends in tropopause characteristics for annual and solsticial seasonal means are presented here, ...