The combining/dividing tee presents a very unique challenge theory wise.  No set equations have been developed for the hydraulic analysis of these tees, only graphs based on extensive testing done by D.S. Miller (published in Internal Flow Systems, copyright D.S. Miller).  Innovative Hydraulics has taken the time to analyze these graphs and develop K value tables based on the data presented in the graphs, and those K value tables have been included as part of Visual Hydraulics.  Based on the information provided by the user (diameters of the tee, approximate flow split, and angle of the tee), the software determines a K value, which in turn is used to determine the appropriate head loss.

Open Channel Contraction/Expansion:

It is not uncommon to encounter a channel that changes width, and this change in width is typically done as a transition rather than abruptly.  Transitions may be either channel contractions or expansions.  Based on the information provided by the user (type of transition, respective widths of the channel, channel invert, and flow), the software will determine a K value for the transition's characteristics.  This K value is then multiplied by the velocity in the channel to determine the relative head loss of the transition.

Rectangular Notched Weir:

The rectangular notched weir is very similar in operation to the v-notch weir, with the rectangular notches provided more flow capacity than the v-notch.  Typical installations of the rectangular notch occur as clarifier or other process tank effluent weirs.  Single larger rectangular notch weirs may be used in some scenarios.  For analysis by Visual Hydraulics, the user provides the invert of the weir notches, size of the notches, number of notches, and flow over the weir.