(Similarity) The Coefficient Of Discharge At The Bottom Intake Weir With A Screen Of A Circular Perforated Plate

The purpose of this study is to find the value of the discharge coefficient (Cd) on a sieve with a circular perforated
plate so that it can be used for application in the field. The method used is to make a physical model test of the screen weir
in the laboratory with a width of 40 cm and a length of 797 cm, then the screen is made variations in the diameter of the
hole 6, 8, 10 and 12 mm, flowrate Q = 453–4 481 cm
3
–1
∙s
and the slope of the screen θ = 20–45°. The result was quite ef-
fective, the sediment did not enter above the screen and did not clog the screen even the catch was quite good about 80% of
the screen rods. The discharge coefficient (Cd) is directly proportional to the square value of the number Froude (Fr), the
slope of the screen (θ) and the ratio of distance, diameter of the screen (a:d) and inversely proportional to the value of the
specific energy square (E). From modelling the average value of the discharge coefficient (Cd) between 0.1–2.75 with
NSE = 0.71, MAE = 0 and RMSE = 0.12.
Key words: bottom intake, circular perforated plate, discharge coefficient, screen