An experimental and analytical study has been made of some features of the turbulent heat diffusion behind a line heated wire stretched perpendicular to a flowing isotropic turbulence. The mean temperature distributions have been measured with systematic variations in wind speed, size of turbulence producing grid, and downstream location of heat source. The nature of the temperature fluctuation field has been studied. A comparison of Lagrangian and Eulerian analyses for diffusion in a nondecaying turbulence yields an expression for turbulent-heat-transfer coefficient in terms of turbulence velocity and a Lagrangian "scale." A convenient form has been deduced for the criterion of interchangeability of instantaneous space and time derivations in a flowing turbulence.

This comprehensive book is based on the Navier-Stokes and other continuum equations for fluids. It interprets the analytical and numerical solutions of the equations of fluid motion. Topics included are turbulence, and how, why, and where it occurs; mathematical apparatus used for the representation and study of turbulence; continuum equations used for the analysis of turbulence; ensemble, time, and space averages as they are applied to turbulent quantities; the closure problem of the averaged equations and possible closure schemes; Fourier analysis and the spectral form of the continuum equations, both averaged and unaveraged; nonlinear dynamics and chaos theory.