A new time scale for turbulence modulation by particles
A new time scale for turbulence modulation by particles
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DOI：
10.1017/jfm.2019.775
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发表时间：
2019-10
影响因子：
3.7
通讯作者：
Izumi Saito;Takeshi Watanabe;T. Gotoh
中科院分区：
文献类型：
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作者：
Izumi Saito;Takeshi Watanabe;T. Gotoh
引入了粒子湍流调制的新时间尺度。该时间尺度与粒子数密度和半径成反比，可以看作是云物理学中重要时间尺度相弛豫时间的对应物，它表征了湍流与云滴之间通过凝结-蒸发的相互作用。均匀各向同性湍流中稀惯性粒子的尺度分析和直接数值模拟表明，具有固定质量载荷参数的粒子对湍流的调制可以表示为达姆克勒数的函数，达姆克勒数定义为湍流大涡周转时间与新时间尺度的比值。
A new time scale for turbulence modulation by particles is introduced. This time scale is inversely proportional to the number density and the radius of particles, and can be regarded as a counterpart of the phase relaxation time, an important time scale in cloud physics, which characterizes the interaction between turbulence and cloud droplets by condensation–evaporation. Scaling analysis and direct numerical simulations of dilute inertial particles in homogeneous isotropic turbulence suggest that turbulence modulation by particles with a fixed mass-loading parameter can be expressed as a function of the Damköhler number, which is defined as the ratio of the turbulence large-eddy turnover time to the new time scale.