The calculations presented in this paper are based on the Sanchez-Lacombe（SL）lattice fluid theory.The interaction energy parameter,g12/k,required in this approach was obtained by fitting the cloud points of polystyr...The calculations presented in this paper are based on the Sanchez-Lacombe（SL）lattice fluid theory.The interaction energy parameter,g12/k,required in this approach was obtained by fitting the cloud points of polystyrene（PS）/methylcyclohexane（MCH）polymer solutions under pressure.The SL lattice fluid theory was used to calculate the spinodals,the binodals,and the Flory-Huggins（FH）interaction parameter of the solutions.The calculated results show that the SL lattice fluid theory can describe the dependences of thermodynamics of PS/MCH solutions on temperature and pressure very well.However,the calculated enthalpy and the excess volume changes indicate that the Clausius-Clapeyron equation cannot be suitable to describe pressure effect on PS/MCH solutions.Further analysis on the thermodynamics of this system under pressure shows that the role of entropy is more important than the excess volume in the present case.展开更多
The wavy （oscillatory both in space and in time） properties of free-surface flows due to presence of floating bodies are analyzed within the framework of the potential-flow theory by assuming that the fluid is perfe...The wavy （oscillatory both in space and in time） properties of free-surface flows due to presence of floating bodies are analyzed within the framework of the potential-flow theory by assuming that the fluid is perfect and flow irrotational. A so-called new multi-domain method has been developed based on the fluid domain division by an analytical control surface surrounding bodies and the application of different methods adapted in the external and internal domains. In the analytical domain external to the control surface, the fundamental solution satisfying the linear boundary condition on the free surface associated with a point singularity （often called Green fimction and referred here as point solution） is applied to capture all wavy features of free-surface flows extending horizontally to infinity. Unlike classical studies in which the control surface is discretized, the unknown velocity potential and its normal derivatives are expressed by expansions of orthogonal elementary functions. The velocity potential associa- ted with each elementary distribution （elementary solutions） on the control surface can be obtained by performing multi-fold inte- grals in an analytical way. In the domain internal to the control surface containing the bodies, we could apply different methods like the Rankine source method based on the boundary integral equations for which the elementary solutions obtained in the external domain playing the role of Dirichlet-to-Neumarm operator close the problem.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.20574069,20490220,50303017,50373044and50340420392)Programs of the Chinese Academy of Sciences(No.KJCX2-SW-H07)the National Basic Research Program ofChina(No.2003CB615600).
文摘The calculations presented in this paper are based on the Sanchez-Lacombe（SL）lattice fluid theory.The interaction energy parameter,g12/k,required in this approach was obtained by fitting the cloud points of polystyrene（PS）/methylcyclohexane（MCH）polymer solutions under pressure.The SL lattice fluid theory was used to calculate the spinodals,the binodals,and the Flory-Huggins（FH）interaction parameter of the solutions.The calculated results show that the SL lattice fluid theory can describe the dependences of thermodynamics of PS/MCH solutions on temperature and pressure very well.However,the calculated enthalpy and the excess volume changes indicate that the Clausius-Clapeyron equation cannot be suitable to describe pressure effect on PS/MCH solutions.Further analysis on the thermodynamics of this system under pressure shows that the role of entropy is more important than the excess volume in the present case.
文摘The wavy （oscillatory both in space and in time） properties of free-surface flows due to presence of floating bodies are analyzed within the framework of the potential-flow theory by assuming that the fluid is perfect and flow irrotational. A so-called new multi-domain method has been developed based on the fluid domain division by an analytical control surface surrounding bodies and the application of different methods adapted in the external and internal domains. In the analytical domain external to the control surface, the fundamental solution satisfying the linear boundary condition on the free surface associated with a point singularity （often called Green fimction and referred here as point solution） is applied to capture all wavy features of free-surface flows extending horizontally to infinity. Unlike classical studies in which the control surface is discretized, the unknown velocity potential and its normal derivatives are expressed by expansions of orthogonal elementary functions. The velocity potential associa- ted with each elementary distribution （elementary solutions） on the control surface can be obtained by performing multi-fold inte- grals in an analytical way. In the domain internal to the control surface containing the bodies, we could apply different methods like the Rankine source method based on the boundary integral equations for which the elementary solutions obtained in the external domain playing the role of Dirichlet-to-Neumarm operator close the problem.
