Maps of the multi-holdup regions in co-current and countercurrent flows are presented in
terms of the controlling non-dimensional parameters. These maps clearly demonstrate the
symmetrical relationship between upward and downward co-current inclined flows. The
feasibility of obtaining multi-holdups in co-current up flow is validated experimentally using
oil–water system. The multiple holdups are shown to be associated with hysteresis
phenomenon. The introduction of the multi-holdup regions on flow-pattern maps of various …