%0 Journal Article
%@ 0001-1541
%A Ducci, A
%A Weheliye, WH
%D 2014
%F discovery:1446921
%I Wiley-Blackwell
%J AIChE Journal
%K Mixing, Orbitally Shaken Bioreactor, viscosity, circulation time, dissipation rate, kinetic energy, fluid mechanics
%N 11
%P 3951-3968
%T Orbitally Shaken Bioreactors - Viscosity effects on flow characteristics
%U https://discovery.ucl.ac.uk/id/eprint/1446921/
%V 60
%X Phase resolved PIV measurements were carried out to assess the flow dynamics occurring in orbitally shaken bioreactors of cylindrical geometry when working fluids of increasing viscosity are considered. Study of the phase-resolved flow characteristics allowed to built a Re-Fr map, where four quadrants associated to di fferent flow regimes are identifi ed: in-phase toroidal vortex (low Fr, high Re), out-of-phase precessional vortex (high Fr, high Re), in-phase single vortex (low Fr, low Re), out-of-phase counter-rotating toroidal vortex (high Fr, low Re). Turbulence levels are found to be significant cant only in the top right quadrant (high Fr, low Re) and scaling of the turbulent kinetic energy obtained with fluid of varying viscosity is obtained by employing the ratio of the operating Froude number to the critical Froude number associated to the mean flow transition, Fr=Frc. Estimates of the mean flow strain deformation as well as of the flow dissipative scale are provided, while a comparison is made between the flow circulation times obtained for di fferent regimes.