to augment heat transfer between two flowing fluids, it is proposed to insert a 100-mm-long, 5-mm-diameter 2024 aluminum pin fin through the wall separating the two fluids. the pin is inserted to a depth of d into fluid 1. fluid 1 is air with a mean temperature of 10°c and velocity of 10 m/s. fluid 2 is air with a mean tempera- ture of 40°c and velocity of 3 m/s.