In this work we study the hydrodynamics of flow around the tubes of a single-row fin-tube heat exchanger. The study includes numerical analysis using finite elements and flow visualization experiments in a water tunnel. It is found that the nature of the flow is greatly affected by the distance between fins. For small distances, the flow is of the Hele-Shaw type without separation. As the distance between fins is increased, a separated region is formed behind the tube which may become unsteady and lead to vortex shedding. Also affected in a similar fashion by the distance between fins is the horseshoe vortex that exists just upstream of the cylinder.