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Transonic Flow Around a Fan Blade

HS Shadowgraphy at Ma_1=1.22

High-speed shadowgraphy at Ma1 = 1.22

Shadowgraphs are recorded at 10khz and show both the motion of the lambda shock above the suction side of the blades as well as the vibrations of the blade surface.

PIV snap-shots of shock wave boundary layer interaction at a 'fixed' shock position at Ma_1=1.2

PIV snap-shots of the shock-wave boundary-layer interaction (SWBLI) at a 'fixed' shock position at Ma1 = 1.2

The incoming flow upstream of the exhibits a low degree of turbulence (Tu1=0.5%), whereas the transitional boundary layer exhibits strong flow separations.

PIV snap-shots of shock wave boundary layer interaction at Ma_1=1.2 with increased in-flow turbulence

Condition with higher in-flow turbulence

The incoming flow upstream of the air involves a high degree of turbulence (Tu1=2.5%). The transitional boundary layer exhibits weak flow separations . Large-scale flow structures occur occasionally.

Conditionally averaged flow field

Conditional averaged flow fields obtained by bin-averaging of shock position at Ma1 = 1.22

Sequence showing the mean velocity fi eld at ' fixed' shock positions obtained by sorting of 10,000 samples followed by conditional averaging. The transitional separation bubble is highlighted through the red line showing an estimated dividing streamline. These conditional averages clearly indicate an increasing size of the separation region with increasing chord-wise shock position.