SIMULATION OF TURBULENT DISPERSION USING WEIERSTRASS MODES

A simple fractal model is proposed for the dispersion of passive scala rs in an incompressible homogeneous turbulent flow field. The dispersi on process is based on a three-dimensional velocity field which is ass umed to be a linear superposition of Taylor-Green vortices with wave n umbers and amplitudes as those in a Weierstrass function. The chosen v elocity field satisfies the continuity equation as well as Kolmogorov' s inertial range power law, and has a fractal dimension D between uppe r and lower length-scale bounds. A cloud of tracer particles is relase d into the flow field and dispersed by the fluid motion, the trajector ies are numerically integrated from the velocity field. The puffs whic h result from this process are used to examine some aspects of turbule nt dispersion, through comparisons with integrated concentration wind- tunnel measurements. The agreement between numerical and experimental results indicates the significance of the proposed simulation model.