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Turbulent jet; counterflow; penetration length; computational fluid dynamics; similarity solution.

The mean flowfield of a turbulent jet issuing into a confined, uniform counterflow was investigated computationally. Based on dimensional analysis, the jet penetration length was shown to scale with jet-to-counterflow momentum flux ratio. This scaling and the computational results reproduce the well-known correct limit of linear growth of the jet penetration length for the unconfined case when the momentum flux ratio is small. However, for the high momentum flux ratio case corresponding to the confinement, the jet penetration length is shown to reach an asymptotic limit of about 3.57 times the confining duct diameter. This conclusion is contrary to the existing results which predict indefinite growth. A simple modification of an existing similarity solution for the jet in an unconfined counterflow provides a convenient framework for presenting the results of the flowfield and jet penetration length.

M Sivapragasam¹ M D Deshpande¹ S Ramamurthy² P White³

1. Department of Automotive and Aeronautical Engineering, M S Ramaiah School of Advanced Studies, Bangalore 560 058, India
2. National Civil Aircraft Development Programme, National Aerospace Laboratories, Bangalore 560 017, India
3. Faculty of Engineering and Computing, Coventry University, Coventry CV1 5FB, UK

Published

June 2014

Manuscript received

26 November 2012

Manuscript revised

9 November 2013

Accepted

21 November 2013