Investigation on multi-objective optimization and flow control mechanism of a bird-inspired bionic geometry for compressor cascades

Inspired by the wing structure of the Grey Heron, this paper proposes a bird‐inspired bionic geometry. A multi‐objective optimization is performed with the total pressure loss coefficients at design (0°) and near‐stall (10°) incidences as objective functions. The optimal geometry reduces the mass-flow-average total pressure loss by 6.19% at the design incidence and by 10.22% at near-stall incidence. The optimal bionic geometry reduces aerodynamic losses mainly by suppressing dissipation in the trailing‐edge and wake regions. The suction‐side groove reshapes the suction‐surface pressure gradient, balancing blade loading and weakening the concentrated shedding vortex in the separation region. Meanwhile, the wavy trailing edge structure creates a localized low-pressure gradient zone near the trailing edge, which inhibits the trailing edge wrapping flow. Shapley additive explanations analysis reveals that increasing groove depth and moving its starting point toward the leading edge reduce aerodynamic losses and improve the flow field. However, the optimal period of the wavy trailing edge varies with incidence: a larger period is favorable for loss reduction at the design incidence, whereas a smaller period yields better performance at the near-stall incidence condition. Compared with the design incidence, a larger amplitude A of the wavy trailing edge is preferred at the high-incidence condition.