Normal depth equations for wide rectangular and triangular open channel sections involving Lambert's W function

Abstract

Normal depth is a key parameter occurring in open-channel hydraulics. For all practical canal sections, open channel resistance equation involves an implicit form for normal depth. Therefore, determination of normal depth involves the tedious method of trial and error. Presented herein are the exact equations for normal depth in terms of Lambert's W function for triangular and wide rectangular open channel sections.

Keywords:

• canals
• Lambert's W function
• normal depth
• open channel
• resistance and uniform flow