On the impact of Reynolds number on the performance of a trenched shaped hole

The present paper reports the results of a combined aerodynamic and thermal experimental investigation carried out on a Plexiglas flat plate model with a set of three fan-shaped holes recessed into a trench. Pressure Sensitive Paint and stereo Particle Image Velocimetry techniques were used to characterize the adiabatic film cooling effectiveness and the flow behavior of the standard shaped hole case and of an optimized trench configuration. The aero-thermal performance has been examined at various mainstream Reynolds numbers and different coolant to mainstream blowing ratios M in the range between 1 and 2. Additionally, Large Eddy Simulations (LES) were also conducted for various mainstream Reynolds numbers at a fixed M = 1.5 to compare the cooling performance with the measurement. This data set allows to fully assess the performance of the trenched fan-shaped hole and to further appreciate the prediction capability of LES approach in simulating film cooling related phenomena.