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Numerical simulations of boundary-layer transition induced by a cylinder wake. (English) Zbl 1082.76053
Summary: Direct and large-eddy simulations of the interaction between a laminar boundary layer and a von Kármán vortex street behind a circular cylinder are carried out for three values of the Reynolds number based on the cylinder diameter and free-stream velocity: $$\text{Re}_D= 385$$, 1155 and 3900. Rapid, bypass-like transition to turbulence is observed in the two higher-Reynolds-number cases. Flow statistics in the transitional and turbulent regions are examined, followed by an investigation of the underlying transition mechanism. Qualitative similarities between wake-induced transition and bypass transition due to free-stream turbulence are discussed and the challenges of predicting boundary-layer transition in this complex environment are pointed out.

MSC:
 76F06 Transition to turbulence 76F65 Direct numerical and large eddy simulation of turbulence
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