Question

For a fully developed laminar flow in a circular pipe, the velocity profile is given by u(r) = 2(1 - r^2/R^2), where R is the radius of the pipe.
a) u(r) = 2 - 2r^2/R^2
b) u(r) = 2 + r^2/R^2
c) u(r) = 2(1 + r^2/R^2)
d) u(r) = 2(1 - 2r^2/R^2)