Horizontal transitions are required for economic and practical reasons for
irrigation works like bridges, weirs and barrages in natural and artificial open channels.
The transitions may be contracting or expanding suddenly or gradually while the flow is
I
either subcritical or supercritical. The problem is solved using the specific energy
i principle. Most of the previous researches solved the problem neglecting the head loss
(theoretical solution).
The author presents in this research paper a new approach to solve the problem for
I horizontal transition for rectangular open channels.
i The specific energy equation in this paper takes a real condition in consideration for
i both contracting and expanding problems. The practical horizontal transitions cases are
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solved taking into consideration the head loss due to contracting or expanding. Also, this
research paper deals with the problem of channel section while contracting with amount
greater than that of critical one. If the contraction of bed is increased further, the
maximum b, and the specific energy were both held constant with this contraction, the
discharge will be decreased until the given specific energy is equal to minimum one
corresponding to the new discharge, because the energy cannot be increased without
outside affect. Consequently the upstream water depth will be changed to a new value.