On the asymmetry of structures in turbulent boundary layers

Turbulence‐producing events in the buffer region of a turbulent boundary layer were found to be associated with a significant probability of a nonzero spanwise velocity component at the time of maximum Reynolds stress. The conditional structures were reconstructed for various levels of spanwise velocity perturbations using the stochastic estimation. The resulting fields exhibit a marked asymmetry with one dominating vortical structure instead of a pair of counter‐rotating ones.