Trident Convection in a Cube

The authors numerically investigate the influence of the forced oscillation upon the three-dimensional thermal convection in a cubic cavity heated from one wall and chilled from its opposite wall in the gravity and zero-gravitaty fields without/with a forced sinusoidal oscillation. The direction of the forced oscillation is parallel to the temperature gradient direction. In addition, the direction is parallel to the direction of the gravity, in the gravity field. The authors assume incompressible fluid with a Rayleigh number Ra = 8.0 × 10⁴ in the gravity field without the forced oscillation or Ra = 1.0 × 10⁴ in the gravity field and a Prandtl number Pr = 7.1 (water). The forced-oscillation parameters are a vibrational Rayleigh number Ra _η and a non-dimentional forced-oscillation frequency ω. In the gravity field, Ra _η  = 1.0 × 10⁵ and ω = 5.0 × 10⁰, and in the zero-gravity field, Ra _η  = 1.1 × 10⁵ and ω = 5.0 × 10⁰. As a result, supposes reports a new flow structure in laminar and steady thermal convection, which consists of a pair of trident currents, namely, three ascending streams and three matching descending streams in a cube heated from a bottom wall and chilled from its opposite top wall. This flow is rather robust. Then, it can be observed in a stationary cube under the gravity, and can be observed in an oscillating cube under the gravity or zero gravity besides.