A simplified version of the correct boundary conditions for skewed turbulence in Lagrangian particle models

Recently, Thomson and Montgomery (1994, Atmospheric Environment28, 1981–1987) stated the correct method of treating the reflection of particle velocity at the boundaries in Lagrangian particle diffusion models for non-Gaussian turbulence. Unfortunately, this method does not have an analytical solution. Two different approximated analytical solutions are proposed and compared. It is concluded that both of them satisfy the well-mixed condition and do not appreciably depart from the correct solution. The one consuming less time is proposed.