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Numerical Analysis of Flow Evolution in a Helium Jet Injected into Ambient AirA computational model to study the stability characteristics of an evolving buoyant helium gas jet in ambient air environment is presented. Numerical formulation incorporates a segregated approach to solve for the transport equations of helium mass fraction coupled with the conservation equations of mixture mass and momentum using a staggered grid method. The operating parameters correspond to the Reynolds number varying from 30 to 300 to demarcate the flow dynamics in oscillating and non-oscillating regimes. Computed velocity and concentration fields were used to analyze the flow structure in the evolving jet. For Re=300 case, results showed that an instability mode that sets in during the evolution process in Earth gravity is absent in zero gravity, signifying the importance of buoyancy. Though buoyancy initiates the instability, below a certain jet exit velocity, diffusion dominates the entrainment process to make the jet non-oscillatory as observed for the Re=30 case. Initiation of the instability was found to be dependent on the interaction of buoyancy and momentum forces along the jet shear layer.
Document ID
20050060866
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Satti, Rajani P.
(Oklahoma Univ. Norman, OK, United States)
Agrawal, Ajay K.
(Oklahoma Univ. Norman, OK, United States)
Date Acquired
August 22, 2013
Publication Date
January 1, 2005
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
HT-FED-2004-56811
Meeting Information
Meeting: 2004 ASME Heat Transfer/Fluids Engineering Summer Conference
Location: Charlotte, NC
Country: United States
Start Date: July 11, 2004
End Date: July 15, 2004
Funding Number(s)
CONTRACT_GRANT: NAG3-2388
Distribution Limits
Public
Copyright
Other

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