Navier–Stokes Equations and Bulk Viscosity for a Polyatomic Gas with Temperature-Dependent Specific Heats

Temperature-dependent bulk viscosity of nitrogen gas determined from spontaneous Rayleigh-Brillouin scattering.

Values for the bulk viscosity η(b) of molecular nitrogen gas (N2) were derived from spontaneous Rayleigh-Brillouin scattering at ultraviolet wavelengths (λ=366.8 nm) and at a 90° scattering angle. Analysis of the scattering profiles yields values showing a linear increasing trend, ranging from η(b)=0.7×10(-5) to 2.0×10(-5) kg·m(-1)·s(-1) in the temperature interval from 255 to 340 K. The presen...

Dynamic equations and bulk viscosity near the gas-liquid critical point

We derive dynamic equations of the mass, energy, and momentum densities to describe dynamics of highly compressible fluids near the gas-liquid critical point. In particular, the complete expression for the stress tensor is presented, which is nonlinear with respect to the fluctuations of the mass and energy densities. The most dominant nonlinearity in the stress tensor can then be identified an...

Bulk viscosity of a gas of massless pions

Bulk viscosity and the conformal anomaly in the pion gas.

We calculate the bulk viscosity of the massive pion gas within unitarized chiral perturbation theory. We obtain a low-temperature peak arising from explicit conformal breaking due to the pion mass and another peak near the critical temperature, dominated by the conformal anomaly through gluon condensate terms. The correlation between bulk viscosity and conformal breaking supports a recent QCD p...

Efficiency of Atkinson Engine at Maximum Power Density using Temperature Dependent Specific Heats

Thermodynamic analysis of an ideal air-standard Atkinson cycle with temperature dependant specific heat is presented in this paper. The paper outlines the effect of maximizing power density on the performance of the cycle efficiency. The power density is defined as the ratio of the power output to the maximum cycle specific volume. It showed significant effect on the performance of the cycle ov...