2025/12/12 by Ben-Shlomo, David, Berkovich, Ronen, Fattal, Eyal
Engineering · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Turbulent Flows #Lattice Boltzmann Simulation Studies #Particle Dynamics in Fluid Flows
paper · doi:10.48550/arxiv.2512.11586
openalex publication_date 2025/12/12 · openalex created_date 2025/12/16 · openalex updated_date 2026/07/28
We investigate the validity of the Markovian assumption in modeling near-wall turbulence by analyzing the detachment of micron-sized particles from the viscous sublayer. By coupling direct numerical simulations with a fractional Ornstein-Uhlenbeck process, we demonstrate that while wall shear stress events follow Poissonian occurrence statistics, their internal dynamics exhibit strong temporal persistence (Hurst exponent H ≈ 0.84), indicating non-Markovian memory. We reveal that the successful predictions of Markovian resuspension models stems from their free parameter acting as a phenomenological surrogate for flow memory. We further identify a critical regime transition governed by a wall shear stress events decay rate, λ. We identify a strong intermittency regime (λ< 0.2), where coherent structures exhibit extended temporal correlations that cannot be mimicked by white noise. Conversely, rapid decays (λ> 0.2) generate quasi-random fluctuations that justify the Markovian approximation. These findings offer a new perspective on the physical validity of classical stochastic modeling in wall-bounded flows.