GAUSSIAN VERSUS TOP-HAT PROFILE ASSUMPTIONS IN INTEGRAL PLUME MODELS

The differences between these two approaches are evaluated by comparing the governing equations on which Gaussian and top-hot models are based; and comparing some typical plume predictions generated by each type of model over a range of model parameters. It is shown that, while the profile assumption does lead to differences in the equations which govern plume variable, the effects of these differences on actual plume predictions is small over the range of parameters of practical interest. Since the predictions of Gaussian and top-hat models are essentially equivalent, it can thus be concluded that the additional physical information incorporated into a Gaussian formulation plays only a minor role in mean plume behavior, and that the top-hat approach, which requires the numerical solution of a simpler set of equations, is adequate for most situations where an integral approach would be used.