Numerical simulations of a water quality model in a flooding stream due to dam-break problem using implicit and explicit methods

Abstract

The heavy monsoon rains have been drenched flooding along the rivers and reservoirs. The residents try to construct the sandbag dike to protect their village. If the residents have encountered flood for long period, the water pollutant must be increase. The villagers want to drain the water to another areas. The residents of another village are not agree to receive the drained-polluted water from them. The simulation of water-quality is required to compromise these problem. The simulation process of water-quality model is require the input as the water flow velocities after the villagers dike has been destroyed but there is lack of field data on the flooding period. In this research, the dam-break model is used to describe unsteady dike failure flow. A couple of mathematical models is used to simulate water-quality in the problem. The first model is the dam-break model that provides the velocity fields and elevation of water. The second model is the dispersion model that provides the pollutant concentration fields. A modified Lax-diffusive method for solving a dam-break model is proposed. At each step, the flow velocity fields calculated from the first model are the input into the second model as the field data. The explicit and implicit methods are subsequently employed in the dispersion model. This paper proposes a simply remarkable alteration to the Lax-diffusive method, the implicit methods and the explicit methods so as to make it more accurate without any significant loss of computational efficiency. The numerical techniques indicate that this model can be applied for simulation of water-quality in long-term flooding cases are proposed.