The experimental results show a significant effect of the presence of the ribs on the
heat transfer rate and friction loss over the smooth wall channel. The uniform rib height performs better than
the corresponding non-uniform one. The in-line rib arrangement provides higher heat transfer and friction
loss than the staggered one for a similar mass flow rate. In comparison, the largest e/H rib with inline array
yields the highest increase in both the Nusselt number and the friction factor values but the lowest e/H rib
with staggered array provides the best thermal performance.