Acta Scientiarum Polonorum

In the article described the use of laboratory tests and modern computational techniques to determine the
shape of the free water profile over the sill a long crested weir. The analysis of the trapezoidal weir with
a vertical upstream face and down surface slanted in a 1:1 ratio were performed. Physical model tests were
performed in a laboratory channel width of 0.20 m and length of 4.0 m. Computer simulations using the
VOF method used in CFD fluid mechanics computing techniques using the ANSYS-Fluent programming
environment were conducted. The coordinates of the water profile obtained from numerical simulations are
compared to the measured values. This is confirmed by statistical analyzes that showed excellent correlation
between computational and measurement coordinates.