Numerical studies on a sort of strongly swirling flows

In general, swirling flows in pipes are generated by three means: tangentially inleting medium; guiding fluids by vanes with a certain angle and axially rotating pipe. But experiments of Horii and his co workers discovered that three kinds of apparatuses can also cause swirling flows with none of the three methods. In our work, the velocity fields of the swirling flow took place in one of the three apparatuses were simulated. The results confirmed the phenomenon of asymmetric double vortices evolving into a single vortex and showed the merits of the contracting portion as well as the distinctions between the different inflow manners. By comparison of the results of linear, quadratic and cubic turbulent models, the cubic model's irregularity of breaking symmetry was exposed.