Horizontal convection induced by absorption of solar radiation

In the present study, the formation and development of horizontal convective currents between open water and a shaded area are investigated numerically. Differential solar heating can result from shading aquatic canopy, producing a temperature difference between the shaded and illuminated region. The unsteady two-dimensional Navier-Stokes (NS) equations are used in conjunction with the energy equation, where the latter accounts for the absorption of radiation through an additional source term. The Boussinesq approximation is applied for taking into account the density difference due to temperature difference in the buoyancy term. Two radiation models are being implemented, one based on Beer's law and the other on the Radiative Transfer Equation (RTE). Both models divide the incoming radiation into three bands, each having a specific absorption coefficient. The RTE incorporates the emission and scattering processes, besides the absorption term, while Beer's law model uses only the absorption term. The effect of Grashof number (Gr), ranging from 10^7 to 10^9 , on the characteristics of the convective currents are examined. The numerical results for the current velocity and water temperature profile are presented and compared against available experimental data.