Turbulent Separated Flows: Near-Wall Behavior and Heat and Mass Transfer

This paper was presented at the Eleventh Asian Congress of Fluid Mechanics as an invited/keynote lecture. The lecture summarizes development of physical model for transfer processes in turbulent separated flows. Attention is focused on the factors that have led to significant advances in understanding of the mechanisms of transfer processes in separated flows, which differs from those in traditional attached turbulent flows in channels and zero pressure gradient turbulent flows. The physical model of transfer processes in the near-wall region of turbulent separated and reattached flows based on the assumption of the governing role of generated local pressure gradient that takes place in the immediate vicinity of the wall in separated flow as a result of intense instantaneous accelerations induced by large-scale vortex flow structures is discussed. Similarity laws for mean velocity and temperature profiles and spectral characteristics of the transfer processes resulting in the physical model are confirmed by the available experimental data. The physical model has provided explanations of the well-known empirical heat and mass transfer correlations for turbulent separated flows and other types of flows close in their structure to those of turbulent separated flows.

کلیدواژه ها:

structure of turbulent separated flows ، transport mechanisms ، velocity profile ، temperature profile ، velocity fluctuation spectra ، similarity laws ، ‘two ، thirds power law’