Certain Computational Aspects of Modeling Stratified Environmental/Geophysical Flows Pertaining to Lakes

Abstract

Two intricate issues reiated to environmental hydrodynamics and water quality numerical modeling, with specific application to lakes, are addressed in this report: turbulent closure for stratified flows and transformation of the physical domain into a computational domain. Both problems are very important for the development of an accurate and efficient numerical algorithm intended to simulate thermo-hydrodynamics and transport processes in a lake (pond) cross section. The first section of the report considers the state-of-the art in turbulence modeling of environmental/geophysical flows (e.g. lakes, oceans, atmosphere) particularly in stratified ambiences, where the vertical turbulent transport is significantly hIndered by density stratification. The findings and recommendations stemming from this investigation are reported herein. In the second section of the report, the numerical treatment of irregular lake geometry is described in detail and a simple, efficient mapping transformation is proposed to facilitate the computation in a lake cross section of an arbitrary form.