“…In this study (part 1), the effects of tip gap height-to-span ratio, h/s, on heat/mass transfer on the protruding FC winglet bottom surface have been investigated experimentally with the wide variation of h/s, by employing the naphthalene sublimation technique along with oil film flow visualizations. The companion paper (part 2) [34] will report heat/mass transfer on the tip surface for the plane tip with the FC winglet.…”