Oscillating onset of the Rayleigh–Bénard convection with viscoelastic fluids in a slightly tilted cavity

The oscillating onset of the Rayleigh–Bénard convection with viscoelastic fluids in a slightly tilted two-dimensional rectangular cavity an aspect ratio Γ = 2 was investigated for first time via direct numerical simulation. A series simulations were conducted plane Rayleigh number (Ra) and tilt angle (α∈[0°, 5°]) three Weissenberg numbers [Wi=(0.1,0.15,0.2)] at fixed Prandtl Pr 7.0. evolutionary path (Wi,α)-plane determined, corresponding complex flow structures observed. inclination box delays oscillations Rac as compared to horizontal configuration. Oscillating acquire attributes traveling wave. specific feature case is that periodicity space exists inclined well. However, evolution oscillatory structure very different from counterclockwise cell assimilates clockwise [Zheng et al., “Pattern selection nonlinear fluids,” Phys. Rev. Fluids 7, 023301 (2022)].