The aim of this study was to investigate the effect of sudden contraction on the energy dissipation. In order to achieve the objectives of the present study, a sudden contraction of 15 cm (7.5 cm on each side) was performed in the Froude number range of 2.5 to 7 and a relative critical depth of 2.10 to 3.56. Then the same model was examined numerically using Flow-3D software and RNG (k-ɛ) turbulence model. Experimental and numerical results showed that by increasing the Froude number of upstream sudden contraction, the upstream and downstream relative energy dissipation increases. Also, validation of numerical data with laboratory showed that the results have a very good agreement with the correlation coefficient of 0.995 and the root mean square error of 0.02.
