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 of Re∗ = 590. Three cases are compared: GC, which only has a constant ground cooling, and GCR, which also incorporates radiative cooling effects with varying absorption coefficients of 100,000 and 600,000. The results reveal that turbulence promotes early fog growth by enhancing water vapour 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.