论文标题
雷诺数对具有高度可变流体特性的流动湍流动能交换的影响
Effect of the Reynolds number on turbulence kinetic energy exchanges in flows with highly variable fluid properties
论文作者
论文摘要
在各种低的马赫数湍流流量中研究了与每单位质量湍流动能或速度协方差张量的半径相关的空间和光谱能交换。两个通道壁的温度为293 K和586K。这在壁正常方向上产生了强温度梯度。温度梯度对能量交换的影响，使用该通道的两个直接数值模拟，在平均摩擦雷诺数180和395处。由于局部流动性能的变化以及雷诺德斯数量的差异，温度梯度在热和冷的侧面的能量交换之间产生了不对称的能量交换。在较高的雷诺数下，雷诺数的低数量效应较小，从而减少了热和冷侧之间的不对称性。我们还分解了能量交换，以便在恒定质体等温病例中分别研究平均特性术语，以及特定于具有可变流体特性的流量的热项。重要的热项对流量具有相似的影响。此外，雷诺数低的效应对热项的影响可忽略不计，并且仅影响均值术语。
Spatial and spectral energy exchanges associated with the turbulence kinetic energy per unit mass, or half-trace of the velocity covariance tensor, are studied in an anisothermal low Mach number turbulent channel flow. The temperatures of the two channel walls are 293 K and 586 K. This generates a strong temperature gradient in the wall-normal direction. The effect of the temperature gradient on the energy exchanges is investigated using two direct numerical simulations of the channel, at the mean friction Reynolds numbers 180 and 395. The temperature gradient creates an asymmetry between the energy exchanges at the hot and cold sides, due to the variations of the local fluid properties and low Reynolds number effects. The low Reynolds number effects are smaller at higher Reynolds number, reducing the asymmetry between the hot and cold sides. We also decomposed the energy exchanges in order to study separately the mean-property terms, as found in the constant-property isothermal case, and the thermal terms, specific to flows with variable fluid properties. The significant thermal terms have a similar effect on the flow. Besides, low Reynolds number effects have a negligible impact on thermal terms and only affect mean-property terms.
