A complex network perspective on the electrification of turbulent clouds

Abstract:

In recent years, researchers have applied complex networks models and analysis techniques to fluid dynamics, e.g., spatial characterization of turbulent flow fields and formulation of reduced-order model of unsteady vortical flows. This work attempts to explore how the complex networks based flow field modeling can shed light on the understanding of nonlinear phenomena associated with thunderstorm electrification. Specifically, the objective here is to study the effect of the spatiotemporal characteristics of turbulence on the electrification process. The approach is to construct a networked dynamical system model of the unsteady vortical field inside thunderclouds, in which the turbulent structure and dynamics of the flow are represented by the random coupling among the nodes (i.e., small-scale cells). The preliminary results indicate that the charge density and electric field are stabilized after random coupling (turbulent mixing) is introduced. However, strong randomness seems unconstructive in generating sufficient electric field, although resulting in a faster synchronization of the networked system. The complex network perspective implies that "moderate" turbulence is the favored condition for electrification. Therefore, a qualitative understanding on the role of turbulence in thunderstorm electrification is developed.