论文标题
压力 - 应变相互作用：I。对PI-D的压缩，变形及其影响
Pressure-Strain Interaction: I. On Compression, Deformation, and Implications For Pi-D
论文作者
论文摘要
压力 - 应变相互作用描述了单位体积的速率，即中性流体或等离子体中的大量流量和热能之间的能量速率。该术语被写成压力扩张的总和和粘性加热的无碰撞类似物，称为$ {\ rm pi-d} $，该术语分别隔离了由于可压缩和不可压缩效应而产生的功率密度。已经表明，$ {\ rm pi-d} $可能是负面的，这使其成为无碰撞粘性加热的识别。我们认为，压力应变相互作用的替代分解对于解释潜在物理学可能是有用的。由于$ {\ rm pi-d} $既包含正常的变形又包含剪切变形，因此我们建议将正常变形与压力扩张进行分组，以描述由于融合/分化流量引起的功率密度，其平衡描述了功率密度，纯粹是由于剪切变形而导致的。然后，我们开发一种对压缩，正常变形和剪切变形的动力学理论解释。我们使用结果来确定可以使$ {\ rm pi-d} $负面的物理机制。我们认为，这两种分解对于研究弱碰撞或无碰撞流体和等离子体中的能量转化都可以有用，并讨论了含义。
The pressure-strain interaction describes the rate per unit volume that energy is converted between bulk flow and thermal energy in neutral fluids or plasmas. The term has been written as a sum of the pressure dilatation and the collisionless analogue of viscous heating referred to as ${\rm Pi-D}$, which isolates the power density due to compressible and incompressible effects, respectively. It has been shown that ${\rm Pi-D}$ can be negative, which makes its identification as collisionless viscous heating troubling. We argue that an alternate decomposition of pressure-strain interaction can be useful for interpreting the underlying physics. Since ${\rm Pi-D}$ contains both normal deformation and shear deformation, we propose grouping the normal deformation with the pressure dilatation to describe the power density due to converging/diverging flows, with the balance describing the power density purely due to shear deformation. We then develop a kinetic theory interpretation of compression, normal deformation, and shear deformation. We use the results to determine the physical mechanisms that can make ${\rm Pi-D}$ negative. We argue that both decompositions can be useful for the study of energy conversion in weakly collisional or collisionless fluids and plasmas, and implications are discussed.
