Abstract: A method of cooling a heat source includes the steps of (1) positioning a thermally conductive base in contact with the heat source, the base having a plurality of fins which define a plurality of channels, (2) generating an initial flow of fluid, (3) positioning a baffle in the path of the initial flow of fluid so as to create a primary flow of fluid and a secondary flow of fluid, (4) directing the primary flow of fluid against the plurality of fins so as to form a quantity of spent fluid which is advanced into the channels, (5) directing the secondary flow of fluid into the plurality of channels so as to force the quantity of spent fluid out of the plurality of channels, and (6) repositioning the baffle from a first position to a second position to change the magnitude of the primary flow of fluid. An apparatus for cooling a heat source which splits an initial flow of fluid into a primary flow of fluid and a secondary flow of fluid is also disclosed.