Solution to problem 3-12 in White

v(r)=[(-dp/dx)/(4 mu)] [r1^2-r^2+(r2^2-r1^2) ln (r / r1)/ln (r2 / r1)]

Q/A =[(-dp/dx)/(8 mu)] r2^2 [1 + (r1/r2)^2 - (1-(r1/r2)^2)/ln (r2/r1)]

Delta p= 40 000 Pa (mu=0.02  Pa. s) corresponding to 4 m water column

Delta p=200 000 Pa (mu=0.1 Pa .s) corresponding to 20 m water column