Study on the structure of turbulent shear in wall near layers

Experimental studies were conducted on fully developed turbulent flows of water in a pipe of circular cross section by employing two different measuring techniques: flow visualization by trace particles, and hot-film anemometry. The two techniques demonstrate different descriptive approaches to self-preserving wall turbulence. By hot-film anemometry, the flow field is explored point by point and the turbulence described in terms of average velocities and velocity correlations measured at these points, whereas by the trace-particle flow visualization, the instantaneous three-dimensional velocity field is mapped out in space and time.