A WAY OF PATTERN ANALYSIS OF TURBULENT STRUCTURE OF LOW-FREQUENCY 3EDDY-GROUP IN A CIRCULAR PIPE FLOW

[摘要] References(5)Cited-By(1)Turbulent axial velocity fluctuations at sixteen radial positions in a circular pipe are measured simultaneously, and contour line maps of the velocity are drawn in time-radial position coordinates. On the basis of these maps, the change in velocity radial distribution with time is regarded as a pattern, and the time- and space-scales of the lowerfrequency eddy-group which is predicted to influence the diffusion of fluid element are discussed. By a statistical method based on pattern analysis, the radial distribution of averaged space-scales of eddies is obtained. Additionally, smaller eddies which cannot be found by the statistical method are extracted through direct reading from the contour line maps, and the usefulness of regarding the turbulent flow field as a pattern is made clear.

[关键词] Fluid Mechanics;Turbulent Flow;Circular Pipe;Eddy Group;Pattern Analysis;Radial Space Scale;Contour Line Map