“…This is consistent with the result of a linear stability analysis for an inertialess limit. [56] Secondly, for the initial state 𝑝 = (δ p 1 , 1, δ p 3 ) with the Dirichlet BC 𝑝| y=0,1 = (0, 1, 0) or the Neumann BC ∂ 𝑝/∂ y| y=0,1 = (0, 0, 0); however, the component p 3 may be unstable to perturbations depending on the value of ζ (ν + 1), leading to true 3D spontaneous flows. We use two initial perturbations given by the following: δ p 1 = δ sin(kπy), δ p 3 = δ sin(kπy) for the Dirichlet BC and δ p 1 = δ cos(kπy), δ p 3 = δ cos(kπy) for the Neumann BC, respectively, in our computations.…”