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On the Accuracy and Convergence of Numerical Solution of the

Collision-Coalescence Equation

 

Lian-Ping Wang

Department of Mechanical Engineering

University of Delaware

 

Abstract

 

For hydrodynamic collision kernels, the time evolution of droplet size spectrum is only obtainable through numerical solution. When addressing the effect of air turbulence on the growth rate of cloud droplets, it is necessary to separate out the effect of turbulence-enhanced collision kernel from the numerical dispersion and diffusion errors.  In this talk, I will address the origins of numerical errors and the convergence rates for several numerical methods, including the high-order integral method of Berry and Reinhardt (1974), the linear flux method of Bott (1998), and the linear discrete method of Simmel (2002), and two new methods we have developed in our on-going research. In our own methods, we attempt to introduce a more rigorous and logical procedure to describe the nature of mass transfer and re-distribution due to collision-coalescence among discrete bins. Important implementation details of the new methods as well as quantitative comparisons with results from other methods will be presented.

 

 

Thursday, 6 January 2005, 3:30 PM

Refreshments 3:15 PM

NCAR-Foothills Laboratory

3450 Mitchell Lane

Bldg 2 Auditorium (Rm1022)