MMM SEMINAR NCAR
Towards better understanding and quantification of turbulence effects on collision rates of cloud droplets
Lian-Ping Wang
Department of Mechanical
Engineering
University of Delaware
Abstract
An open issue in cloud microphysics concerns the effects of air turbulence on the spectrum broadening of cloud droplets and development of warm-rain precipitation.
An accurate, quantitative understanding of turbulence effects requires a full knowledge of small-scale air turbulent motion and dynamics of droplet-fluid interactions and droplet-droplet interactions. Direct measurements of the collision-coalescence process in a turbulent flow have not yet been proven possible. In this talk, I will discuss an on-going, systematic effort to address various effects of turbulence on geometric collision rates and collision efficiencies. A methodology for conducting direct numerical simulations of hydrodynamically-interacting droplets in a turbulent background flow in the context of cloud microphysics will be reported along with results on collision rates and collision efficiencies. Recent advances on kinematic formulation of collision rates and theoretical developments on modeling turbulence effects will be discussed.
Thursday, August 26 at 3:30
p.m.
Refreshments 3:15 PM
3450 Mitchell Lane
Bldg 2 (Rm 1022,
Auditorium)