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Results from simulations using FLUENT (a commercial CFD package) are compared with Time Resolved Digital Particle Image Velocimetry (DPIV) for baseline configurations in order to validate and verify the fidelity of the computations. Different turbulent models are used in this study in order to determine which one is the most appropriate. Subsequently a parametric analysis of the flow characteristics as a function of the clearance height of the impeller from the vessel floor is performed. Results are presented along planes normal and parallel to the impeller axis, displaying velocity vector fields and contour plots of vorticity turbulent dissipation and others. Special attention is focused in the neighborhood of the impeller region and the radial jet generated there. The present results provide useful information for the design of the mixing process as well as for more accurate estimations in future work.

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An exact solution of the Navier-Stokes equations for laminar flow inside porous pipes simulating variable suction and injection of blood flows is proposed in the present article. To solve these equations analytically, it is assumed that the effect of the body force by mass transfer phenomena is the 'porosity' of the porous pipe in which the fluid moves. The resultant of the forces in the pores can be expressed as filtration resistance. The developed solutions are of general application and can be applied to any swirling flow in porous pipes.The effect of porous boundaries on steady laminar flow as well as on species concentration profiles has been considered for several different shapes and systems. In certain physical and physiological processes filtration and mass transfer occurs as a fluid flows through a permeable tube. The velocity and pressure fields in these situations differ from simple Poiseuille flow in an impermeable tube since the fluid in contact with the wall has a normal velocity component. In the new flow model, a variation of the solutions with Bessel functions based on Terrill's theoretical flow model is adopted.

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