Direct Numerical Simulation of Turbulent Radiation Fog

Abstract: This study investigates the interplay between turbulent and radiative effects in fog formation using Direct Numerical Simulation (DNS). The simulation is conducted in an open channel with a fixed total amount of cooling at a friction Reynolds Number (Re_tau) of 590. Three cases are compared: GC, which only has constant ground cooling, and GCR, which also incorporates radiative cooling effects with varying absorption coefficients of 100000 and 600000. The results reveal that turbulence promotes early fog growth by enhancing water vapor aggregation, while higher radiative absorption by fog results in more uniform liquid water potential temperature distributions. Both turbulence and radiation contribute to increased liquid water accumulation, revealing complex interactions in fog dynamics and offering insights into fog formation under different conditions. Keywords: Direct Numerical Simulation, Turbulent Channel Flow, Radiation Fog, Condensation Processes