A fluid flows in a laminar regime through either a circular or an equilateral triangular cross-sectional channel. The two channels have equal crosssectional areas, so that the average fluid velocity...

A fluid flows in a laminar regime through either a circular or an equilateral triangular cross-sectional channel. The two channels have equal crosssectional areas, so that the average fluid velocity is the same. Assume thermally developed flow

(a) Determine the ratio of the friction factor–surface area product of the two.

(b) Determine the ratio of the heat transfer coefficient–surface area product of the two.