Wei Yikun, Shen Pingping, Wang Zhengdao, Liang Hong, Qian Yuehong
Joint Engineering Lab of Fluid Transmission System Technology, Faculty of Mechanical Engineering and Automation, Zhejiang Sci-Tech University, Hangzhou 310018, China.
Department of Physics, Hangzhou Dianzi University, Hangzhou 310018, China.
Entropy (Basel). 2020 Jun 17;22(6):672. doi: 10.3390/e22060672.
Time evolution features of kinetic and thermal entropy generation rates in turbulent Rayleigh-Bénard (RB) convection with mixed insulating and conducting boundary conditions at = 10 are numerically investigated using the lattice Boltzmann method. The state of flow gradually develops from laminar flow to full turbulent thermal convection motion, and further evolves from full turbulent thermal convection to dissipation flow in the process of turbulent energy transfer. It was seen that the viscous, thermal, and total entropy generation rates gradually increase in wide range of /τ < 32 with temporal evolution. However, the viscous, thermal, and total entropy generation rates evidently decrease at time /τ = 64 compared to that of early time. The probability density function distributions, spatial-temporal features of the viscous, thermal, and total entropy generation rates in the closed system provide significant physical insight into the process of the energy injection, the kinetic energy, the kinetic energy transfer, the thermal energy transfer, the viscous dissipated flow and thermal dissipation.
利用格子玻尔兹曼方法，对具有混合绝缘和传导边界条件、瑞利数(Ra = 10^6)的湍流瑞利 - 贝纳德（RB）对流中动力学和热熵产生率的时间演化特征进行了数值研究。流动状态从层流逐渐发展到完全湍流热对流运动，并在湍动能传递过程中进一步从完全湍流热对流演变为耗散流。可以看出，在(t/τ < 32)的较宽范围内，粘性、热和总熵产生率随时间演化逐渐增加。然而，与早期相比，在时间(t/τ = 64)时，粘性、热和总熵产生率明显降低。封闭系统中粘性、热和总熵产生率的概率密度函数分布、时空特征为能量注入、动能、动能传递、热能传递、粘性耗散流和热耗散过程提供了重要的物理见解。
