EXPERIMENTS ON THE DIFFUSION OF SMOKE IN ISOTROPIC TURBULENT-FLOW

Detailed properties of the downstream evolution of smoke released in an isotropic turbulent flowfield are reported. Effects of turbulence on the mass-transfer characteristics of the flow, which in turn affect such things as the spread of pollution and the rate of chemical reactions, are studied. Smoke is released a short distance downstream of a uniform grid placed perpendicular to a uniform stream of air in a wind tunnel. A laser Doppler velocimeter is used to make the desired velocity field measurements, and a laser light-scatttering technique provides the “instantaneous” mass fraction c of smoke at the same point in the flowfield. One-point statistical properties of the velocity and concentration fields are obtained. The one-point cross correlations cu and cv are also reported. © 1979 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.