Fluid Flow and Solute Transfer in a Tube with Variable Wall Permeability

We considered a steady flow of viscous incompressible fluid and solute transfer in an axisymmetric tube of uniform cross section with variable wall permeability, which is relevant to the study of movement of solute across the glomerular capillaries. The solutions for the nonlinear governing equations of the fluid flow and solute transfer are obtained by analytical/numerical methods. The combined effect of variable wall permeability and flow parameters on the hydrostatic pressure, osmotic pressure, velocity profiles, concentration profiles, and the total solute clearance are investigated and are presented in this paper. It is found that an increase in the variable permeability parameter increases the solute concentration at the wall.