On the shear number effect in stratified shear flow (Q1964300)

The authors investigate the influence of the shear number on turbulence evolution in a stably stratified fluid. The shear number \(SK/\varepsilon\) is the ratio of a turbulence time scale \(K/\varepsilon\) to the shear time scale \(1/S\). Two series of direct numerical simulations are performed to study the role of this parameter: a moderate Reynolds number series with initial Reynolds number \(\text{Re}_\lambda= 44.72\), and high Reynolds number series with initial Reynolds number \(\text{Re}_\lambda= 89.44\). The Richardson number \(\text{Ri}= 0.15\) is constant in all simulations. The authors find that the shear number affects the spectral space dynamics. Turbulent transport coefficients decrease with increasing shear number.