in fig8 and fig9 the first six transverse rows of fins 67 have an aspect ratio of 6 0 1 the next six transverse columns of fins 68 have an aspect ratio of 5 5 1 the next five transverse columns of fins 69 have an aspect ratio of 5 0 1 the next four transverse columns of fins 70 have an aspect ratio of 4 5 1 the next four transverse columns of fins 71 have an aspect ratio of 4 0 1 the next three transverse columns of fins 72 have an aspect ratio of 3 5 1 the next three transverse columns of fins 73 have an aspect ratio of 3 0 1 the next two transverse columns of fins 74 have an aspect ratio of 2 5 1 the remaining two transverse columns of fins 75 in the first u215e of flow length 65 have an aspect ratio of 2 0 1 referring now to fig8 and fig9 as the fluid absorbs heat and the temperature of the fluid rises lower aspect ratio fins increase the heat transfer coefficient to achieve uniform cooling although a log progression to lower aspect ratios is beneficial the last roughly u215b of the heat sink 66 may contribute a majority of the flow resistance for this reason at about u215e distance along the flow axis the fins progress linearly to high aspect ratios again again referring to fig8 starting at the leading edge of the last u215b of heat sink length 66 the first transverse rows of fins 76 has an aspect ratio of 3 0 1 the next transverse columns of fins 77 has an aspect ratio of 4 0 1 the.