混合流体分离比对摆动行波的影响

Effect of separation ratio in a binary fluid mixture on undulation traveling wave

利用Simple算法对流体力学基本方程组进行了数值模拟,研究了摆动行波的特性。结果表明:在摆动行波存在的范围内,当相对瑞利数r较小时,腔体内沿着空间的平均波数是随着时间周期变化的;当r较大时,腔体内沿着空间的平均波数随着时间增大保持为常数。摆动行波的摆动周期随r的增大而减小;分离比负值越大,变化越平缓,摆动行波出现的范围越大。随着长高比增加,较小分离比时,摆动周期的上、下限明显提高;分离比较大时,摆动行波存在区间对应的r上、下限明显增加。

In this paper, the numerical simulations are made by solving the two-dimensional full equations of hydrodynamics using the Simple algorithm, and the dynamics of undulation traveling wave pattern in binary fluid convection in a rectangular cell is studied. In the existence range of undulation traveling wave, the average wave number in space in the cavity changes with time when reduced Rayleigh number is smaller, and the mean wave number in space in the cavity keeps constant when reduced Rayleigh number is larger. The oscillation period of the undulation traveling wave decreases with the increase of the reduced Rayleigh number. The variation of the oscillation period with the reduced Rayleigh number is slower, and the range appearing the undulation traveling wave is larger when the negative separation ratio is larger. With the increase of the aspect ratio, the upper and lower limits of the oscillation period increase obviously at the small separation ratio, and the upper and lower critical values of the existence of undulation traveling wave are obviously increase at the large separation ratio.