Experimental results for the local heat transfer coefficient hx for flow over a flat plate with an extremely rough surface were found to fit the relation
hx(x) = ax-0.1
where a is a coefficient (W/m1.9 · K) and x (m) is the distance from the leading edge of the plate.
1. Develop an expression for the ratio of the average heat transfer coefficient hx for a plate of length x to the local heat transfer coefficient hx at x.
2. Plot the variation of hx and hx as a function of x.