Author(s): Adrian C. H. Lai; Joseph H. W. Lee
Linked Author(s): Joseph Hun-Wei Lee
Keywords: Lternating diffuser; Computational fluid dynamics (CFD); Laser induced fluorescence; Multiple buoyant jet interaction
Abstract: We present a semi-analytical model to study the dynamic interaction of multiple buoyant jets above an alternating diffuser in stagnant ambient condition. The multiple jet induced flow field is computed by replacing each jet with a distribution of sinks of strength equal to the entrainment per unit length along the jet trajectory. The induced pressure in the external irrotational flow is subsequently obtained by the Bernoulli’s principle, and this dynamic effect is incorporated into the governing equations of a buoyant jet via an exact momentum balance using a control volume approach. The deflected jet trajectory is solved iteratively by incorporating the pressure and momentum flux terms due to the external flow. Laboratory experiments have been carried out for an alternating diffuser discharge using the LaserInduced Fluorescence (LIF) technique. 3D numerical simulations have also been carried out using the 3D Reynolds-averaged Navier-Stokes equations (RANS) combined with a buoyancy-extended k-ε model. The trajectory predicted by the semi-analytical model is generally in reasonable agreement with the observations.