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ISSN オンライン: 2642-0554

A LABORATORY ANALOGUE FOR CLOUD ENTRAINMENT: WHOLE-FIELD VELOCITY AND TEMPERATURE MEASUREMENTS IN A VOLUMETRICALLY HEATED JET

Amit Agrawal
126 Spencer Lab, Department of Mechanical Engineering, University of Delaware, DE 19716, USA

Ajay K. Prasad
126 Spencer Lab, Department of Mechanical Engineering, University of Delaware, DE 19716, USA

要約

Whole-field velocity and temperature measurements were conducted in the axial plane of an axisymmetric turbulent jet to investigate the effect of off-source volumetric heat addition on entrainment in clouds. The jet fluid was selectively heated while the ambient fluid temperature remained unaffected, simulating condensation heat release in clouds. Measurements in the heat injection zone are presented for varying Reynolds number and non-dimensional heat injection rate. Off-source heat addition causes the jet velocity to decay less rapidly, and the characteristic gaussian profile of the streamwise velocity is distorted to a "flat-top" gaussian. The cross-stream velocity experiences an even greater difference: the heated jet shows an inward velocity at all radial positions in the heating zone, in contrast to the outward velocity in the vicinity of the center line for an unheated jet. These differences are linked to the different decay rates of the axial velocity of heated and unheated jets. The ensemble-averaged temperature exhibits an interesting double-peak. Further, the heat injection zone can be divided into three sub-zones with sharp differences in flow properties. A theoretical model incorporating the varying decay rates is proposed.