A printing pigment solution having a viscosity of 0.05 N s /m2 and the yield stress of 0.6 N/m2 flows in a three meter tube which has a diameter of 0.015 m. Calculate the minimum pressure drop required for flow. If the actual pressure drop is twice the minimum, also calculate the followings:
a. The radius of the solid core
b. The velocity of the core
c. The volumetric flow rate