The flow patterns and mixing in a jet agitated vessel were investigated using a computational fluid dynamic (CFD) model. Turbulent flow in a cylindrical vessel, agitated by one or two side entering, horizontal jets was simulated using standard k-epsilon model of turbulence. The predicted results are compared with the published experimental data. The fluid dynamic model of a jet mixer was further used to computationally investigate the possibility of applying external spatially periodic perturbations on jets (in the form of alternating jets) to enhance the mixing performance of the jet mixers. The computational model and results presented here will be useful for evolving better mixing protocols (by manipulating the sequence and frequency of alternating jets).