Experimental investigation of turbulent flow in the inlet region of an eccentric annulus

In a fully eccentric annulus with a radius-ratio of 0.86 the mean flow components and six components of the Reynolds stress tensor were measured. Measurements were made with hot-wire probes. Static pressure and total pressure were determined by static pressure probes and Pitot tubes. Experiments prove that there is a flow reversal directly behind the entrance that covers the total range in azimuthal direction and half the area in radial direction and it induces an enlargement of the velocity in the outer region. There is a secondary flow, which changes substantially over the entrance length. The entrance length is larger than generally thought.