论文标题
$re_λ$和Rouse数字对均质各向同性湍流中惯性粒子的结算的影响
The effect of $Re_λ$ and Rouse numbers on the settling of inertial particles in homogeneous isotropic turbulence
论文作者
论文摘要
我们提出了一项实验研究，该研究对风隧道中活性网格产生的湍流中致密的亚基莫戈罗夫颗粒的沉降速度。使用相位多普勒的干涉法，我们观察到惯性颗粒的沉降速度的修饰，在同质的各向同性湍流和稀释条件下$ ϕ_V \ leq o（10）^{ - 5} $，由泰勒基于Taylor的Reynolds reynolds Number number $re_λ$ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_ RE_RE_λ$控制。相反，我们没有发现流体和重力加速度（即$γ\ sim（η/τ_η^2）/g $）之间比率的强大影响。值得注意的是，我们的结果表明，颗粒所经历的沉降速度的阻碍（即，在静态流体条件下测得的粒子沉降速度小于其各自的速度）随着$re_λ$的值而增加，从而逆转了在中间$re_λ$条件下发现的沉降增强。该观察结果适用于所研究的所有粒径，并且与文献中先前的实验数据一致。在研究的最高$re_λ$中，$re_λ> 600 $，粒子增强体制不再存在。我们的数据还表明，对于中等隆起的数字，在静止流体条件下测得的粒子沉降速度与其速度之间的差异与Rouse线性缩放，当该差异通过载体相位RMS波动归一化时，即$（v_p -v_t）/u \ sim -ro $。
We present an experimental study on the settling velocity of dense sub-Kolmogorov particles in active-grid-generated turbulence in a wind tunnel. Using phase Doppler interferometry, we observe that the modifications of the settling velocity of inertial particles, under homogeneous isotropic turbulence and dilute conditions $ϕ_v\leq O(10)^{-5}$, is controlled by the Taylor-based Reynolds number $Re_λ$ of the carrier flow. On the contrary, we did not find a strong influence of the ratio between the fluid and gravity accelerations (i.e., $γ\sim(η/τ_η^2)/g$) on the particle settling behavior. Remarkably, our results suggest that the hindering of the settling velocity (i.e. the measured particle settling velocity is smaller than its respective one in still fluid conditions) experienced by the particles increases with the value of $Re_λ$, reversing settling enhancement found under intermediate $Re_λ$ conditions. This observation applies to all particle sizes investigated, and it is consistent with previous experimental data in the literature. At the highest $Re_λ$ studied, $Re_λ>600$, the particle enhancement regime ceases to exist. Our data also show that for moderate Rouse numbers, the difference between the measured particle settling velocity and its velocity in still fluid conditions scales linearly with Rouse, when this difference is normalized by the carrier phase rms fluctuations, i.e., $(V_p-V_T)/u\sim -Ro$.
