Bulk Models of Sheared Boundary Layer Convection

Abstract

This paper discusses approaches to constructing bulk convective boundary layer (CBL) models based on the concept of complete mixing. Large-eddy simulation (LES) results are used to test the basic similarity hypotheses. The empirical constants of the bulk CBL model that are obtained from LES data for the case of free convection agree well with previously published data from laboratory experiments. It is also shown that the flux of kinetic energy from the upper CBL boundary transported by gravity waves is small compared with other components of the balance of turbulence kinetic energy (TKE) in the convective layer. The parametrization of TKE generation for the case of a sheared CBL in terms of the friction velocity and the average wind velocity in the CBL is derived; all dimensionless constants of the theoretical model are obtained from LES data. The results allow us to formulate an integral model of the sheared CBL suitable for practical use.