Stream Division by a Channel Bottom Orifice

A particularly important application of devices dividing a stream of liquid is in storm water drainage systems. Dividers of rainwater sewage streams have in recent years aroused considerable interest among producers of separators. It is therefore important to develop mathematically simple and, if possible, physically precise methods of sizing such structures. It is all the more important given that there are few such methods in the literature on hydraulics. This work is meant to partially remedy this deficiency by elaborating on the calculation methodology and by verifying it empirically. A circular orifice at the bottom of the supplying channel is technically the simplest type of stream divider (which makes it higly practical and particularly appealing to producers). A procedure for dimensioning the structure under consideration is proposed here. It is formally simple, being meant as a practical designing tool. This proposal has been verified experimentally. The degree of the division of the stream was measured in a laboratory model. The main issues were the stability of the characteristics of the lateral outflow and the possibility of applying the classical equations of hydraulics to size the type of divider considered here. In both cases the results obtained may be regarded as positive. Admittedly, the output of the lateral outflow exceeds the nominal value for greater inflows Qp, but it is at most double the nominal value. From a technical point of view, this may be regarded as a good result, considering the simplicity of the system. The answer to the second issue proved even more satisfactory. It turns out that the formally simple hydraulics relationships provide a technically consistency of theory with measurement results. Thus the designing of objective devices does not require the application of difficult, time-consuming and costly methodology.