Numerical Study on the Coupled Impact of Periodic Wake and Pulsating Jet on Film Cooling Efficiency on a Flat Wall

This paper presents a numerical study investigating the coupled effects of periodic incoming wake and pulsating jets on the film cooling efficiency of a flat wall. The sweeping frequency of the wake is maintained at a constant 10 Hz, while the blowing ratio (M) varies from 0.3 to 1. By adjusting the initial position of the rod, different phase lags are generated to assess the interaction between the incoming wake and the pulsating jet concerning film cooling efficiency. The results reveal that coupling the wake-affected surface with the low-blowing-ratio phase of the pulsating jet can effectively enhance film cooling efficiency at lower blowing ratios. Conversely, at higher blowing ratios, aligning the low-pressure phase of the pulsating jet at the film hole with the high-blowing-ratio jet pulsation results in an improved film cooling effect. Notably, when the phase lag (ψ) is set to zero, the cooling efficiency of the pulsating film reaches its maximum across all blowing ratios, indicating an optimal coupling strategy.