Churuksaeva V.   Starchenko A.  

Numerical modeling of pollution transport in a river flow

Reporter: Churuksaeva V.

The purpose of this work is to construct a mathematical model and a computational method to get extensive knowledge about the structure of a river stream that is the essential basis for minimizing damage and making predictions about the behavior of the river.
The model proposed is based on depth-integrated RANS equations. Averaged turbulent stresses appearing in the model were defined from Boussinesq’s hypothesis. Turbulent characteristics of the flow were computed from the depth averaged high-Reynolds modification of the k-epsilon turbulence model. The model also includes wind stresses on water surface, bottom share stresses depending on roughness, and terms to account for the Coriolis force that are significant for the flow in a river.
A finite volume method on the staggered structured grid was used to discretize the equations. Convective fluxes were discretized with the third order MUSCLE scheme. Solution of the discrete system was obtained with a SIMPLE iterative algorithm based on coupled correction of the depth and velocity fields on each time step. The principal innovation of the algorithm proposed is accounting for the variability of the water depth in the source term in the momentum equations.
The main object of the research is the 50 km section of the Tom River near the city of Tomsk. Possible scenarios for the transport of pollutants from wastewater discharge into the river and the areas that could be affected by local flooding from spring snow melt and ice flow were modeled and the results show agreement with general concepts and represent flow patterns observed in field studies.