Round turbulent puffs and buoyant thermals in uniform Crossflows

F. J. Diez, O. C. Kwon, R. Sangras, L. P. Bernal, G. M. Faeth

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


The properties of round nonbuoyant turbulent puffs, and buoyant turbulent thermals in uniform crossflows were studied both experimentally and theoretically, motivated by applications to interrupted gas and liquid releases caused by process upsets, explosions and unwanted fires, among others. Emphasis was placed on self-preserving conditions far from the source where extraneous source disturbances have been lost, where flow properties are largely controlled by the conserved properties of the flow, and where properly scaled flow properties become independent of both distance from the source and time. The experiments involved injecting dye-containing turbulent round water puffs and thermals into a uniform crossflow produced by a 610 x 610 mm crosssection water tunnel facility and observing the flow with CCD cameras. Near-source properties varied significantly with source properties but the flows became turbulent and then self-preserving within 5 and 30-40 source diameters in the vertical direction (aligned with the source puff/thermal) from the source, respectively. Within the self-preserving region, the vertical penetration distance generally varied as a function of time in accord with self-preserving predictions. Flow in the self-preserving region, also satisfied the assumption of no slip crosstream convection at the mean crosstream velocity, yielding a simple and convenient way of predicting flow trajectories. Radial penetration distances of the flows also satisfied the general scaling relationships for puffs and thermals in still fluids but with the added complication that the flow was no longer axisymmetric about the axis of the trajectory. Finally, when amounts of source fluid injected became large for puffs and thermals, self-preserving behavior for starting jets and plumes was achieved before the source flow was terminated and the flow was best considered to be an interrupted jet or plume rather than a puff or a thermal.

Original languageEnglish (US)
Title of host publication8th AIAA/ASME Joint Thermophysics and Heat Transfer Conference
PublisherAmerican Institute of Aeronautics and Astronautics Inc.
ISBN (Print)9781624101182
StatePublished - 2002
Externally publishedYes
Event8th AIAA/ASME Joint Thermophysics and Heat Transfer Conference 2002 - St. Louis, MO, United States
Duration: Jun 24 2002Jun 26 2002

Publication series

Name8th AIAA/ASME Joint Thermophysics and Heat Transfer Conference


Other8th AIAA/ASME Joint Thermophysics and Heat Transfer Conference 2002
Country/TerritoryUnited States
CitySt. Louis, MO

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Nuclear and High Energy Physics


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