Three-dimensional LDA measurements in the impeller region of a turbulently stirred tank

Three-dimensional, angle-resolved LDA measurements of the turbulent flow field (Re = 2.9 × 10⁴) in the vicinity of a Rushton turbine in a baffled mixing tank have been performed. For this goal, a procedure for accurate beam alignment, based on a submerged micro-mirror system, has been developed. Results on the average flow field as well as on the complete set of Reynolds stresses are presented. The anisotropy of the turbulence has been characterized by the invariants of the anisotropy tensor. The trailing vortex structure, which is characteristic for the flow induced by a Rushton turbine, is demonstrated to be associated with strong, anisotropic turbulent activity. Received: 14 September 1998/Accepted: 22 February 1999