Nonlinear Dynamics of Turbulent Thermals in Shear Flow

On the Nonlinear Dynamics of Turbulent Thermals in the Shear Flow

“…In a recent paper by the author [1] a theoretical study was made of the problem of the motion of a turbulent thermal in a horizontal shear flow using the well-known model of turbulent convection from localized sources of buoyancy and (or) momentum, which act for a short timeisolated thermals (see, for example, [2][3][4][5][6][7] and references therein). In such a model, the region of perturbation (thermal) is approximately represented in the form of an ascending (or descending, depending on the sign of perturbation) "bubble" or vortex ring of variable volume and mass.…”

“…In [1] the problem is generalized to the important case where the thermal can move at an angle to the vertical. Such situations arise in a natural way when a thermal rises or descends in a horizontal flow with a vertical shift.…”

“…As the thermal moves in such a flow, it also acquires a horizontal velocity relative to the background flow. Accordingly, the generalization of the first equation of (1.1) in [1] has the form…”

“…In the simplest cases, integral heat release in such a thermal can be taken to be constant: Q = const. The case of unstable background stratification of the surrounding medium, when N 2 < 0, was not considered in [1]. This case is of interest, in particular, in connection with the abovementioned mechanism of generation of microgusts in the atmosphere.…”