On the stability and bifurcation of the non-rotating Boussinesq equation with the Kolmogorov forcing at a low Péclet number

Autor: Yiqiu Mao, Quan Wang, Chanh Kieu, Zhimin Chen
Rok vydání: 2020
Předmět:
Zdroj: Communications in Nonlinear Science and Numerical Simulation. 89:105322
ISSN: 1007-5704
DOI: 10.1016/j.cnsns.2020.105322
Popis: This study examines the stability and potential bifurcations of a stratified shear flow governed by the non-rotating incompressible Boussinesq equation at a low Peclet number. For the ratio of the vertical scale to the horizontal scale of a stratified flow a ∈ [ 3 / 4 , 3 / 2 ) , it is shown that there exists a threshold for the Reynold number Re above which the steady stratified shear flow driven by the Kolmogorov forcing becomes linearly unstable. As a result, the Boussinesq equation exhibits a Hopf bifurcation. To further determine the type of the Hopf bifurcation, the model is reduced to a low-order system whose numerical analyses reveal that the Hopf bifurcation is supercritical. That is, a stable periodic solution emerges, which describes an oscillating thermal convection in a highly stratified shear flow arising in the atmosphere or interior of many stellar systems with low Peclet numbers.
Databáze: OpenAIRE