Coherent motions and their role in the turbulent transport process of heat.

Abstract

An objective method for the recognition and description of coherent structures is developed and applied to identify the role of coherent motions in the turbulent heat transport process i n a pipe. Four distinct patterns are recognized in the sequence of coherent motions near the wall. These four basic flow patterns have their own characteristic eddy structures and reflect the succession of stages that might occur in the evolution of coherent motions . Also these recognized patterns can delineate the mechanistic picture of turbulent heat transport in the wall region. among other things, the important finding is that the outflowing low-momentum wall-region fluid organizing strong eddy motions with the incoming higher-momentum fluid from regions away from the wall is the principal contributor to the turbulent exchange process of heat. The other types of ejections are not necessarily important in turbulent heat transfer.