A pharmaceutical company is developing a topical gel formulation that contains 0.5% (w/w) polyacrylic acid as a thickener in 50% (v/v) glycerin. The gel will be applied to the skin for the treatment of psoriasis. The flow rate of the gel through a cylindrical tube with a diameter of 5 mm and a length of 20 cm is to be determined, assuming laminar flow.

Assumptions:

Incompressible flow

Steady State flow

Constant properties (viscosity, density and temperature)

The velocity of the gel at the walls of the tube is zero, due to the no-slip condition

Pressure drop is assumed to be atmospheric pressure (1atm = 101325Pa)