The mechanism by which nonlinearity sustains turbulence in plane Couette flow

摘要: Turbulence in wall-bounded shear flow results from a synergistic interaction between linear non-normality and nonlinearity which non-normal growth of subset perturbations configured to transfer energy the externally forced component turbulent state perturbation maintains energy, while energy-transferring is replenished by nonlinearity. Although it accepted that both mediated mean nonlinear interactions among are required maintain state, detailed physical mechanism these processes interact maintaining turbulence has not been determined. In this work statistical dynamics based analysis performed on Couette at R = 600 comparison DNS used demonstrate parametric process fluctuating streamwise adjusted marginal Lyapunov stability. It further shown alternative subspace non-normally growing maintained directly perturbation-perturbation does contribute state. This identifies varying be associated vectors with positive energetics as structures supporting turbulence.