Experimental study of near-field entrainment of moderately overpressured jets

Journal of Fluids Engineering
By: , and 

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Abstract

Particle image velocimetry (PIV) experiments have been conducted to study the velocity flow fields in the developing flow region of high-speed jets. These velocity distributions were examined to determine the entrained mass flow over a range of geometric and flow conditions, including overpressured cases up to an overpressure ratio of 2.83. In the region near the jet exit, all measured flows exhibited the same entrainment up until the location of the first shock when overpressured. Beyond this location, the entrainment was reduced with increasing overpressure ratio, falling to approximately 60 of the magnitudes seen when subsonic. Since entrainment ratios based on lower speed, subsonic results are typically used in one-dimensional volcanological models of plume development, the current analytical methods will underestimate the likelihood of column collapse. In addition, the concept of the entrainment ratio normalization is examined in detail, as several key assumptions in this methodology do not apply when overpressured.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Experimental study of near-field entrainment of moderately overpressured jets
Series title Journal of Fluids Engineering
DOI 10.1115/1.4004083
Volume 133
Issue 5
Year Published 2011
Language English
Publisher ASME
Publisher location New York, NY
Contributing office(s) Cascades Volcano Observatory
Description 12 p.; 051304
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Fluids Engineering
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