A comparison of the trajectories of rising buoyant plumes with theoretical/empirical models

Abstract

The trajectory of a plume of hot gas from a power station is shown to be well represented by the equation $\text{z =}\text{AQ}{}^{0.25}\text{x}{}^{\mathrm{\ast 0.75}}\text{U}$ where z is the rise above the source (m), Q is the rate of heat emission (MW), U is the wind speed at 1.5 stack heights (m s⁻¹) and $\text{x}{}^{\mathrm{\ast }}\text{(m)}$ is a function of the distance downwind, atmospheric stability and stack height, $\text{x}{}^{\mathrm{\ast }}$ is approximately equal to the distance downwind at distances up to a few hundred metres and approaches an asymptotic value of 1 km or more at large distances (i.e. of a few km) in unstable and near neutral meteorological conditions and of a few hundred metres at moderate distances (< 1 km) with stable lapse rates.