Particle image velocimetry (PIV) study of rotating cylindrical filters for animal cell perfusion processes

In the present work, the main fluid flow features inside a rotating cylindrical filtration (RCF) system used as external cell retention device for animal cell perfusion processes were investigated using particle image velocimetry (PIV). The motivation behind this work was to provide experimental fluid dynamic data for such turbulent flow using a high‐permeability filter, given the lack of information about this system in the literature. The results shown herein gave evidence that, at the boundary between the filter mesh and the fluid, a slip velocity condition in the tangential direction does exist, which had not been reported in the literature so far. In the RCF system tested, this accounted for a fluid velocity 10% lower than that of the filter tip, which could be important for the cake formation kinetics during filtration. Evidence confirming the existence of Taylor vortices under conditions of turbulent flow and high permeability, typical of animal cell perfusion RCF systems, was obtained. Second‐order turbulence statistics were successfully calculated. The radial behavior of the second‐order turbulent moments revealed that turbulence in this system is highly anisotropic, which is relevant for performing numerical simulations of this system. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012     

A Study of Sedimentation and Resuspension in the Near-Bottom Boundary Layer Using Cylindrical Traps in Hydrobiological Investigation

An inexpensive and convenient method for marine biological investigation of the sedimentation in the immediate proximity of biological objects on the seabed is considered. The method is a modification of the widespread method of cylindrical sediment traps [1,6]. It makes it possible to analyze the amount of suspended particulate matter passing within the near-bottom boundary layer and the processes of sedimentation and resuspension. Its application is illustrated by the results of investigation of the influence of some processes taking place in the near-bottom layer on the distribution of scleractinian corals in a reef off Dao-Chao Island (Baitylong Archipelago, the Gulf of Tonkin).