论文标题
旋转对法拉第不稳定驱动的湍流混合的影响
Effect of rotation on turbulent mixing driven by the Faraday instability
论文作者
论文摘要
使用直接数值模拟（DNS）研究了旋转对两个小对比度密度的湍流的湍流。我们证明，在较低的强迫幅度下，T.K.E.随着f的增加（f/ω\ right）^2 <0.25的增加，其中强迫频率是在亚谐波不稳定阶段。 T.K.E.的增加增加B_V，这增加了总势能（TPE）。 TPE的一部分是猿。猿的某些部分可以通过b_v转换为$ t.k.e. $，而其余部分则转换为内部能量，通过ϕ_i增加BPE。其余的TPE还通过diapynal通量ϕ_d转换为BPE，从而导致不可逆的混合。随着不稳定性的饱和，不可逆的混合停止。当（f/ω\ right）^2> 0.25时，科里奥利的力显着延迟了亚谐波不稳定性的发作。在此期间，初始浓度曲线扩散以增加TPE，最终在BPE中花费了。强烈的旋转效应抑制了T.K.E ..因此，B_V和APE变小，大部分TPE花费了BPE。由于不稳定永远不会以$ \ left（f/ω\右）^2> 0.25 $饱和，因此$ b_v $保持非零，从而导致TPE持续增加。通过$ ϕ_d $将TPE转换为BPE，我们发现了长时间的不可逆混合。在较高的强迫幅度下，旋转的稳定效果可以忽略不计，湍流较少且短暂。因此，不可逆转的混合现象也以$ \ left（f/ω\ right）^2 <0.25 $快速结束。但是，当$ \左（f/ω\右）^2> 0.25 $时，观察到连续混合。我们发现，湍流混合在较低的强迫幅度和旋转速率（f/ω）^2> 0.25时有效。
The effect of the rotation on the turbulent mixing of two miscible fluids of small contrasting density, produced by Faraday instability, is investigated using direct numerical simulations (DNS). We demonstrate that at lower forcing amplitudes, the t.k.e. increases with an increase in f till (f/ω\right)^2<0.25, where ωis the forcing frequency, during the sub-harmonic instability phase. The increase in t.k.e. increases B_V, which increases the total potential energy (TPE). A portion of TPE is the APE. Some parts of APE can convert to $t.k.e.$ via B_V, whereas the rest converts to internal energy, increasing BPE through ϕ_i. The remaining TPE also converts to BPE through the diapycnal flux ϕ_d resulting in irreversible mixing. With the saturation of the instability, irreversible mixing ceases. When (f/ω\right)^2 > 0.25, the Coriolis force significantly delays the onset of the sub-harmonic instabilities. During this period, the initial concentration profile diffuses to increase TPE, which eventually expends in BPE. The strong rotational effects suppress t.k.e.. Therefore, B_V and APE become small, and the bulk of the TPE expends to BPE. Since the instability never saturates for $\left(f/ω\right)^2 > 0.25$, the $B_V$ remains non-zero, resulting in a continuous increase in TPE. Conversion of TPE to BPE via $ϕ_d$ continues, and we find prolonged irreversible mixing. At higher forcing amplitudes, the stabilizing effect of rotation is negligible, and the turbulence is less intense and short-lived. Therefore, the irreversible mixing phenomenon also ends quickly for $\left(f/ω\right)^2<0.25$. However, when $\left(f/ω\right)^2>0.25$ a continuous mixing is observed. We find that the turbulent mixing is efficient at lower forcing amplitudes and rotation rates of (f/ω)^2 > 0.25.
