Laboratory Investigation of Flow Characteristics of a Sutro Weir

Linear proportional weirs are sharp crested weirs in which discharge of water is linearly proportional to the head over the weir crest. They tend to have high accuracy when compared with the nonlinear ones. The main objective of the study was to investigate the flow characteristics of Sutro weir as a linear weir in an open channel. In addition, the effects of the width of the base (s) and the radius (R) of the curved section on the head measured above the weir sill were monitored. The experiments were conducted in a flume having a working length of 6 m with a cross section 0.3 m wide and 0.3 m deep. A total of 45 laboratory experiments were carried out on nine different models for five different discharges. The models made of wood were grouped into two sets of which the first set consisted of five models of constant radius of 9 cm and varying base heights. The second set consisted of four models of constant weir base height of 4 cm and varying curve radius. The experimental results obtained showed that the radius (R) of the curved section had more effect on the head measured above the weir sill compared with the width of the base. The set two models showed a better linear relationship between the actual discharge and the head measured above the weir sill compared to the set one models.