Question: Consider steady flow in a tube with a fully developed velocity profile at the tube entrance. Let the fluid temperature at the tube entrance be uniform at t; Then let the tube surface temperature vary axially according to the relation
t0 - te = a[exp (bx+) - 1]
b
where a and b are arbitrary constants. Derive an expression for the local Nusselt number as a function of Show that all members of this family of solutions lead to Nusselt numbers that are independent of X + at sufficiently large values of X ". What are the implications of this result? Discuss how the constant b affects the asymptotic Nusselt number.