Estimation of bulk viscosity of dilute gases using a nonequilibrium molecular dynamics approach

Bulk viscosity of dilute monatomic gases

“…This is because the gas becomes more and more dilute with the increasing temperature and decreasing pressure, thereby making dense gas effects less important. This trend is different from that for other gases, such as dilute nitrogen gas, where a weak pressure dependency and linear temperature dependency are observed at similar pressures and temperatures [30,31]. The reason for this contrasting behavior is that both gases have different source mechanisms of bulk viscosity, as discussed in the next paragraph.…”

“…There are primarily two mechanisms responsible for deviation of equilibrium pressure from non-equilibrium pressure-(a) The slow exchange of translational energy with internal degrees of freedom. A brief review of this mechanism can be found somewhere else [30]. This mechanism is only present in polyatomic fluids as the monatomic molecules do not have rotational or vibrational energies.…”

Impact of bulk viscosity on flow morphology of shock-accelerated cylindrical light bubble in diatomic and polyatomic gases

“…While Stokes' hypothesis is believed to be valid in the case of monatomic gases such as argon, there is growing proof that this is not the case with diatomic and polyatomic gases such as nitrogen, methane, and carbon dioxide. [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] Examples of such cases include the inner structure of strong shock waves in diatomic gases and hypersonic entry into the Mars atmosphere, which consists mostly of carbon dioxide. A recent experimental study on the second-mode instability in the laminar-toturbulence transition in hypersonic boundary layers 40 showed that, for a real diatomic gas, the growth and decay of the second mode are accompanied by a dilatation process that leads to a 50% increase in dilatation dissipation in comparison with Stokes' hypothesis.…”

“…In Fig. 3(a), the computed shear viscosity is compared with the experimental data of Vogel, 66 the theoretical results using the Green-Kubo method, 47 and the computational results of Hanley and Elye 64 and Billing and Wang. 65 The selected potential law replicates…”

Global existence versus blow-up for multi-d hyperbolized compressible Navier-Stokes equations

“…The latter is not only motivated because it is mathematically accessible with respect to local existence and blow-up, but also with a physical background. In fact, there are recent studies determining the volume viscosity of a variety of gases which were found to be much larger (factor 10 4 ) than the corresponding shear viscosities, see [32].…”