A parameter analysis of a two-phase flow model for supersaturated total dissolved gas downstream spillways

A high concentration of the total dissolved gas (TDG) in a flow downstream high dams may cause the gas bubble disease in fishes. To better understand the spatial distribution of a supersaturated TDG, a numerical simulation approach for determining the TDG concentration is shown to be effective and convenient; however, the determination of the model parameters relies to a great extent on the observed field data, which are scarce but are very sensitive to the accuracy of the simulation. In this regard, determining the source parameter in the TDG transport equation is the primary concern of this paper. Observed field data from six different spillways in China are used to calibrate the source parameter. A relationship between the source parameter and the hydrodynamic characteristics is established. The inclusion of this relationship in the predictive relationship will enable an accurate and rapid estimation of the source parameter and may help in developing mitigation measures for the TDG supersaturation downstream the spillways.