Lattice Boltzmann study of flow and mixing characteristics of two-dimensional confined impinging streams with uniform and non-uniform inlet jets

Previous works have shown that impinging streams are susceptible to instabilities which will lead to asymmetric and deflecting flows. The inlet velocity profiles as one factor may affect the flow, temperature and mixing characteristics of this flow, which are very important in practical applications and little considered in previous works. In the present work, these characteristics for two inlet velocity profiles (uniform velocity and parabolic velocity, two representative profiles) at different configuration parameters (H/W = 1-4, H and W are the jets' separation and inlet width) and Reynolds numbers (Re = 10-200) are studied numerically via lattice Boltzmann method and compared in detail. In particular, the temperature characteristics with and without the buoyancy effects are investigated. The simulation results show that the inlet velocity profiles have strong influences on these characteristics at larger H/W and Re, which confirm that impinging streams are easily affected by the inlet velocity profiles. (C) 2012 Elsevier Ltd. All rights reserved.