Resumé
| Originalsprog | Engelsk |
|---|---|
| Artikelnummer | 034503 |
| Tidsskrift | Journal of Chemical Physics |
| Vol/bind | 138 |
| Udgave nummer | 3 |
| Antal sider | 9 |
| ISSN | 0021-9606 |
| DOI | |
| Status | Udgivet - 2013 |
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Generalized extended Navier-Stokes theory : Correlations in molecular fluids with intrinsic angular momentum. / Hansen, Jesper Schmidt; Daivis, Peter; Dyre, J. C.; Todd, Billy; Bruus, Henrik.
I: Journal of Chemical Physics, Bind 138, Nr. 3, 034503, 2013.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review
TY - JOUR
T1 - Generalized extended Navier-Stokes theory
T2 - Correlations in molecular fluids with intrinsic angular momentum
AU - Hansen, Jesper Schmidt
AU - Daivis, Peter
AU - Dyre, J. C.
AU - Todd, Billy
AU - Bruus, Henrik
PY - 2013
Y1 - 2013
N2 - The extended Navier-Stokes theory accounts for the coupling between the translational and rotational molecular degrees of freedom. In this paper, we generalize this theory to non-zero frequencies and wavevectors, which enables a new study of spatio-temporal correlation phenomena present in molecular fluids. To discuss these phenomena in detail, molecular dynamics simulations of molecular chlorine are performed for three different state points. In general, the theory captures the behavior for small wavevector and frequencies as expected. For example, in the hydrodynamic regime and for molecular fluids with small moment of inertia like chlorine, the theory predicts that the longitudinal and transverse intrinsic angular velocity correlation functions are almost identical, which is also seen in the molecular dynamics simulations. However, the theory fails at large wavevector and frequencies. To account for the correlations at these scales, we derive a phenomenological expression for the frequency dependent rotational viscosity and wavevector and frequency dependent longitudinal spin viscosity. From this we observe a significant coupling enhancement between the molecular angular velocity and translational velocity for large frequencies in the gas phase; this is not observed for the supercritical fluid and liquid state points.
AB - The extended Navier-Stokes theory accounts for the coupling between the translational and rotational molecular degrees of freedom. In this paper, we generalize this theory to non-zero frequencies and wavevectors, which enables a new study of spatio-temporal correlation phenomena present in molecular fluids. To discuss these phenomena in detail, molecular dynamics simulations of molecular chlorine are performed for three different state points. In general, the theory captures the behavior for small wavevector and frequencies as expected. For example, in the hydrodynamic regime and for molecular fluids with small moment of inertia like chlorine, the theory predicts that the longitudinal and transverse intrinsic angular velocity correlation functions are almost identical, which is also seen in the molecular dynamics simulations. However, the theory fails at large wavevector and frequencies. To account for the correlations at these scales, we derive a phenomenological expression for the frequency dependent rotational viscosity and wavevector and frequency dependent longitudinal spin viscosity. From this we observe a significant coupling enhancement between the molecular angular velocity and translational velocity for large frequencies in the gas phase; this is not observed for the supercritical fluid and liquid state points.
U2 - 10.1063/1.4774095
DO - 10.1063/1.4774095
M3 - Journal article
VL - 138
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 3
M1 - 034503
ER -