论文标题
温度场湍流运输中的可压缩性效应
Compressibility effects in a turbulent transport of temperature field
论文作者
论文摘要
研究了适用于小péclet数字的准线性方法的湍流传输场中的可压缩性效应，并针对大péclet数字进行光谱$τ$方法。流体流量的可压缩性降低了平均温度场的湍流扩散率与颗粒数密度和磁场的湍流相似。但是，可压缩湍流中平均温度场的湍流扩散系数的表达与平均颗粒数密度和平均磁场的表达式不同。可压缩性和不均匀性的结合作用会导致区域平均温度的升高，由于湍流泵送而导致更强烈的速度波动。正式地，这种作用类似于以前发现的可压缩涡流现象[J。血浆物理。 {\ bf 84}，735840502（2018）]用于非惯性颗粒或气态混合物。平均流体压力的梯度导致平均温度场的额外湍流。后一种效果类似于颗粒和气态混合物的湍流Barodifusion。流体流的可压缩性还导致周围流体的湍流冷却，这是由于平均温度场方程中的其他水槽项。对颗粒的这种影响没有类似物。
Compressibility effects in a turbulent transport of temperature field are investigated applying the quasi-linear approach for small Péclet numbers and the spectral $τ$ approach for large Péclet numbers. Compressibility of a fluid flow reduces the turbulent diffusivity of the mean temperature field similarly to that for particle number density and magnetic field. However, expressions for the turbulent diffusion coefficient for the mean temperature field in a compressible turbulence are different from those for the mean particle number density and the mean magnetic field. Combined effect of compressibility and inhomogeneity of turbulence causes an increase of the mean temperature in the regions with more intense velocity fluctuations due to a turbulent pumping. Formally, this effect is similar to a phenomenon of compressible turbophoresis found previously [J. Plasma Phys. {\bf 84}, 735840502 (2018)] for non-inertial particles or gaseous admixtures. Gradient of the mean fluid pressure results in an additional turbulent pumping of the mean temperature field. The latter effect is similar to turbulent barodiffusion of particles and gaseous admixtures. Compressibility of a fluid flow also causes a turbulent cooling of the surrounding fluid due to an additional sink term in the equation for the mean temperature field. There is no analog of this effect for particles.
