A Fundamental Study of Supercritical Flow at Sudden Expansion Structure by Using Numerical Model

River Engineering and Urban Drainage Research Centre (REDAC), Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, Penang, Malaysia.

^* Corresponding author: redac_puay@usm.my

Abstract

In the design of hydraulic structures, it is common to deal with the supercritical flow. Abrupt expansion structure represents a type of transition often constructed in manmade hydraulic structure (e.g. chutes in dam structures, sewer or drainage system, an irrigation channel, etc.) to cater the geometry difference. It is important to cater to the design of such transition especially it involves flow with high velocity. The flow features of high-velocity flow at sudden expansion channel are studied. A two-dimensional depth-averaged model (DA model) incorporate with Constrained Interpolation Profile (CIP) scheme is developed to simulate the supercritical flow at the abrupt expansion channel. The numerical model is able to reproduce the flow features of supercritical flow at the abrupt expansion structure. The simulated results are compared with the analytical solution with a different degree of agreement is observed. The same numerical setup is applied to the model generated by FLOW-3D model. The numerical results from the DA model and FLOW-3D model are compared with previous experimental results. The simulated results from the DA model showed better agreement with the experimental results.