NUMERICAL STUDY ON FLOW CHARACTERISTICS OF A SINGLE JET AND MULTIPLE TANDEM JETS IN CROSSFLOW

The flow dynamics of a single jet and four tandem jets in cross flow were simulated using the Computational Fluid Dynamics (CFD) code Fluent. The realizable k-epsilon model was used to close the Reynolds-Averaged equations. The flow characteristics of the jets, including jet trajectory, velocity field and turbulent kinetic energy, were compared at the jet to cross flow velocity ratio of R = 2.38 - 17.88. The single jet is found to penetrate slightly deeper than the first jet in a jet group at the same R, although discrepancy decreases with decreasing R. The way that the velocity decays along the centerline of the jet is similar for a single jet and the first jet in a group, and the speed of the decay increases with decreasing R. The downstream jets in a group behave differently due to the sheltering effect of the first jet in the group. Compared with the first jet, the downstream jets penetrate deeper into the cross flow, and the velocity decays slower. The circulation zone between the two most upstream jets is stronger than those formed between downstream jets.