水平流动对周期加热的Rayleigh-Bénard对流的影响

Influence of Horizontal Flow on Rayleigh-Bénard Convection with Periodic Heating

采用二维流体力学基本方程组对普朗特数Pr=0.0272的具有水平流动周期性加热的Rayleigh-Bénard对流特性进行数值模拟.结果说明,当相对瑞利数给定时,对流斑图的形成取决于水平流动强度.由对流斑图随着时间的变化确定了对流周期.随着相对瑞利数的减小,对流周期适应的水平流动强度减小,并且水平流动强度的存在范围减小.随着相对瑞利数的增加,对流周期变小.随着水平流动强度的增加,对流周期变小,并且对流周期变化的梯度变小.随着水平流动强度的增加,两个局部行波对流区的范围减小,水平流动区间增加.然后,随着水平流动强度的进一步增加,第一对流区先消失.当水平流动强度足够大时第二对流区也消失.腔体内形成水平流动.随着相对瑞利数的增大,第一对流区和第二对流区消失的临界水平流动强度也增大.

The Rayleigh-Bénard convection heating periodically with horizontal flows in the Prandtl number Pr = 0.0272 is numerically simulated by using two-dimensional basic equations of fluid mechanics. The results show that the formation of the convection pattern depends on the horizontal flow intensity Re for a given reduced Rayleigh number r. The convection period is determined by the variation of convection pattern with time. As the reduced Rayleigh number r decreases, the horizontal flow intensity Re adapted to the convective period decreases, and the range of horizontal flow intensity Re decreases. With the increase of reduced Rayleigh number r, the convection period decreases. With increasing horizontal flow intensity Re, the convective period decreases and the gradient of convective period decreases. With the increase of horizontal flow intensity Re, the range of two localized traveling wave convection zones decreases and the horizontal flow zones increase. Then, with the further increase of horizontal flow intensity Re, the first convection zone disappeared. When the horizontal flow intensity Re is large enough, the second convection zone also vanishes. Horizontal flow is formed in the cavity. With the increase of the reduced Rayleigh number r,the critical horizontal flow intensity of the disappearance of the first and second convective regions also increases.