Various soft materials share some common features, such as significant entropic effect, large fluctuations, sensitivity to thermodynamic conditions, and mesoscopic characteristic spatial and temporal scales. However, ...Various soft materials share some common features, such as significant entropic effect, large fluctuations, sensitivity to thermodynamic conditions, and mesoscopic characteristic spatial and temporal scales. However, no quantitative defini- tions have yet been provided for soft matter, and the intrinsic mechanisms leading to their common features are unclear. In this work, from the viewpoint of statistical mechanics, we show that soft matter works in the vicinity of a specific thermo- dynamic state named moderate point, at which entropy and enthalpy contributions among substates along a certain order parameter are well balanced or have a minimal difference. Around the moderate point, the order parameter fluctuation, the associated response function, and the spatial correlation length maximize, which explains the large fluctuation, the sensitivity to thermodynamic conditions, and mesoscopic spatial and temporal scales of soft matter, respectively. Possible applications to switching chemical bonds or allosteric biomachines determining their best working temperatures are also briefly discussed.展开更多
The comparative study on seven equation models with two different six equations modelfor compressible two-phase flow analysis is proposed. The seven equations model isderived for compressible two-phase flow that is in...The comparative study on seven equation models with two different six equations modelfor compressible two-phase flow analysis is proposed. The seven equations model isderived for compressible two-phase flow that is in the nonconservation form. In thepresent work, two different six equations model are derived for two pressures, two velocities and single temperature with the derivation of the equation of state. The closingequation for one of the six equations model is energy conservation equation while anotherone is closed by entropy balance equation. The partial differential form of governingequations is hyperbolic and written in the conservative form. At this point, the set ofgoverning equations are derived based on the principle of extended thermodynamics.The method of solving single temperature from both six equation models are simple anddirect solution can be obtained. Numerical simulation has been tried using one of the sixequation models for air–water shock tube problems. Explicit fourth order Runge–Kuttascheme is used with Finite Volume Shock Capturing method for solving the governingequations numerically. The pressure, velocity and volume fraction variations are captured along the shock tube length through flow solver. Experimental work is carried outto magnify the initial stage of liquid injection into a gas. The outcome of six equationsmodel for compressible two-phase flow has revealed the multi-phase flow characteristicsthat are similar to the actual conditions.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2013CB932804)the National Natural Science Foundation of China(Grant Nos.11274319 and 11421063)
文摘Various soft materials share some common features, such as significant entropic effect, large fluctuations, sensitivity to thermodynamic conditions, and mesoscopic characteristic spatial and temporal scales. However, no quantitative defini- tions have yet been provided for soft matter, and the intrinsic mechanisms leading to their common features are unclear. In this work, from the viewpoint of statistical mechanics, we show that soft matter works in the vicinity of a specific thermo- dynamic state named moderate point, at which entropy and enthalpy contributions among substates along a certain order parameter are well balanced or have a minimal difference. Around the moderate point, the order parameter fluctuation, the associated response function, and the spatial correlation length maximize, which explains the large fluctuation, the sensitivity to thermodynamic conditions, and mesoscopic spatial and temporal scales of soft matter, respectively. Possible applications to switching chemical bonds or allosteric biomachines determining their best working temperatures are also briefly discussed.
文摘The comparative study on seven equation models with two different six equations modelfor compressible two-phase flow analysis is proposed. The seven equations model isderived for compressible two-phase flow that is in the nonconservation form. In thepresent work, two different six equations model are derived for two pressures, two velocities and single temperature with the derivation of the equation of state. The closingequation for one of the six equations model is energy conservation equation while anotherone is closed by entropy balance equation. The partial differential form of governingequations is hyperbolic and written in the conservative form. At this point, the set ofgoverning equations are derived based on the principle of extended thermodynamics.The method of solving single temperature from both six equation models are simple anddirect solution can be obtained. Numerical simulation has been tried using one of the sixequation models for air–water shock tube problems. Explicit fourth order Runge–Kuttascheme is used with Finite Volume Shock Capturing method for solving the governingequations numerically. The pressure, velocity and volume fraction variations are captured along the shock tube length through flow solver. Experimental work is carried outto magnify the initial stage of liquid injection into a gas. The outcome of six equationsmodel for compressible two-phase flow has revealed the multi-phase flow characteristicsthat are similar to the actual conditions.
