Particle Dispersion in a Turbulent Shear Flow
Annual rept. 15 May 1989-14 May 1990
CALIFORNIA UNIV DAVIS
Pagination or Media Count:
A joint experimental and numerical study of droplet dispersion in a round turbulent jet has been initiated. Laser light scattering was used to measure the motion of non-vaporizing droplets of water and hexadecane in an isothermal turbulent jet of air. The results indicated that an initial radial velocity fluctuation in the droplet motion at the jet exit can serve to increase significantly the dispersion of droplets larger than 100 microns. Vortex dynamics simulations of the near region of the jet showed that Basset, virtual mass and pressure gradient forces may be neglected for small droplets but may need to be accounted for, particularly at high pressure, with large droplets 100 microns even if the drop to gas density ratio is close to one. A stochastic simulation of particle dispersion revealed that the Reynolds stresses or velocity correlations in this flow do not contribute significantly to particle dispersion. Keywords Turbulent shear flows, Particle dispersion, Vortex dynamics, Stochastic simulation.
- Fluid Mechanics