A Preliminary Study of Turbulence Characteristics of Flow Along a Corner

In the turbulent flow of a fluid along a corner, secondary flows occur which have a marked influence on the velocity distributions in planes normal to the mean flow direction. All published explanations of the cause of these secondary flows deal with the turbulent structure of the flow. In this paper, measurements of isotach patterns and directional turbulence intensities in the corner of a rectangular channel with zero pressure gradient and a range of free-stream turbulence intensity of 0.8 to 2.3 per cent are reported. (An isotach is a constant velocity line in a plane normal to the mean flow direction.) Within the range of variables investigated, the following conclusions are drawn: (a) Isotach patterns are essentially independent of free-stream turbulence intensity; (b) at any point the ratio of turbulence components in orthogonal directions in a plane normal to the mean flow direction is a maximum for directions tangent and normal to the isotach at that point; (c) the ratio w^′/v^′, where w^′ and v^′ are turbulence components, respectively, tangent and normal to the isotach at any point, is always greater than unity; and (d) in the vicinity of the bisector of the corner angle the ratio w^′/v^′ increases with increasing isotach curvature.