Markovian properties of velocity increments in boundary layer turbulence

Highlights: • First paper studying Markovian properties of turbulent boundary layers. • Markovian nature of turbulence evolves across the boundary layer. • Logarithmic behavior below the log-layer. • A constant behavior across the log-layer. • Connection between the spectral gap and Markovian nature of turbulence. Markovian properties of the turbulent velocity increments in a flat plate boundary layer at Re${}_{\theta }$ of $19100$ are investigated using hot-wire anemometry measurements of the streamwise velocity component in a wind tunnel. Increments of the longitudinal velocities at different wall-normal positions show that the flow exhibits Markovian properties when the separation between different scales, or the Markov–Einstein coherence length, is on the order of the Taylor microscale, $\lambda$. The results indicate that Markovian nature of turbulence evolves across the boundary layer showing certain characteristics pertaining to the distance to the wall. The connection between the Markovian properties of turbulent boundary layer and existence of the spectral gap is explored. Markovianity of the process is also discussed in relation to the nonlocal nonlinear versus local nonlinear transfer of energy, triadic interactions and dissipation.