Single-row film holes were drilled on flat plates

and experimental tests were performed to investigate the cylindrical-hole (CH) film cooling in the presence of upstream sand-dune-shaped ramp (SDR) under four typical blowing ratios of 0.5

1.0

1.5 and 2.0 using infrared thermometry method. A straight-wedge-shaped ramp (SWR) was adopted for the comparison. At the same time

numerical simulations were also performed to illustrate different roles of respective upstream ramps on the film cooling enhancement. Results showed that the presence of the upstream sand-dune-shaped ramp helped to generate an additional pair of anti-kidney vortices. As a consequence

the SDR provided a more favorable film cooling enhancement than the SWR. Under a small blowing ratio of 0.5

the area-averaged adiabatic film cooling effectiveness in a specific zone (within 15 times of the hole diameter downstream of the film hole) increased about 26% by SWR and 75% by SDR

with respect to the baseline cylindrical-hole situation. Under a high blowing ratio of 1.5

the area-averaged adiabatic film cooling effectiveness could be increased up to 100% and 150%

respectively

by using SWR and SDR.