Enhanced convective heat transfer surfaces have been a subject of interest for quite some time. Many different methods have been used to increase the amount of heat transfered from a surface. However, nearly all surface enhancement methods come with a price, frictional losses. This thesis studies the use of enhanced convective heat transfer surfaces on air fins in the laminar, transitional, and turbulent flow regimes with emphasis on the transitional regime. A major goal of this thesis is to further the understanding of the influence of an enhanced wall geometry on the transition from laminar to turbulent flow. Causing the flow to transition at a lower Reynolds number is typically a desirable effect because heat transfer from the surface is increased with a relatively small frictional loss increase --Abstract, page iii