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Momentum and Scalar Mixing Across Jet-Fluid Interface of Submerged Rectangular Jet

Author(s): Shengcheng Huang; Kit-Ming Lam

Linked Author(s): Kit Ming Lam

Keywords: Rectangular jet; Aspect ratio; Conventional statistics; Conditional sampling

Abstract: The mixing behavior across the jet-fluid interface of a rectangular jet is investigated experimentally with particle image velocimetry (PIV) and laser-induced fluorescence (LIF). The objectives are to understand the inter-relationship between mixing of momentum and dilution of scalar species concentration in a rectangular jet. Conventional statistical analysis of the velocity and scalar concentration data are performed to investigate the global jet behavior, including flow regimes and self-similarity features. Meanwhile, instantaneous data at several points along the jet -fluid interface are observed and analyzed in order to investigate the correlation between concentration and velocity fluctuations in local region. The results show that the rectangular jet exhibits half power law decay of mean centerline velocity after 4 to 5D (D being jet exit height), which can be regarded as quasi-2D region, and within the quasi-2D region, the concentration spreads 34% faster than the momentum. In regions near the jet exit (2 to 2. 5D), velocity and concentration fluctuations are influenced by vortex motions symmetrically across the jet. Beyond 2. 5D, co-presence of large-scale concentration and radial velocity fluctuations are found to occur on one side of the jet only.


Year: 2013

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