We prove that isentropic gas flow does not admit non-degenerate TVD fields on any invariant set M(r0, s0) = {r0 < r < s < s0}, where r, s are Riemann coordinates. A TVD field refers to a scalar field whose spatial variation VarX(φ(τ(t,X), u(t,X))) is nonincreasing in time along entropic solutions. The result is established under the assumption that the Riemann problem defined by an overtaking s...

The current study investigates experimentally the potential of integrating a scroll expander into a micro cogeneration steam Rankine cycle. This expander technology is not an existing technical option for such applications; consequently an existing oil-free scroll compressor is adapted to run in an expander mode with water as working fluid. The performance of the adapted scroll expander, with d...

Ozone depletion above Kiruna (67.9N, 21.1E), Sweden, was investigated using daily ozone and temperature measurements by ozonesondes between 1 February and 25 March 1997. Using UKMO Ertel’s potential vorticity (EPV) and wind fields, three dynamically distinct regions were defined on a grid of isentropic surfaces viz.: the polar vortex boundary region characterized by steep EPV gradients, the are...

A major question for climate studies is to quantify the role of turbulent eddy fluxes in maintaining the observed atmospheric mean state. Both the equator-to-pole temperature gradient and the static stability of the extratropical atmosphere are set by a balance between these eddy fluxes and the radiative forcing. Much attention has been paid to the adjustment of the isentropic slope, which rela...

For the purpose of engineering, it is important to study convergent rates in process low Mach number limit. However, there are only a few results on this issue, which focus cases isentropic regime or ones without solid boundaries. In paper, we obtain convergence for local strong solutions non-isentropic compressible Navier-Stokes equations with well-prepared initial data and Navier-slip boundar...

Starting from a standard description of an ideal, isentropic fluid, we derive the effective theory governing a gapless non-relativistic mode—the sound mode. The theory, which is dictated by the requirement of Galilei invariance, entails the entire set of hydrodynamic equations. The gaplessness of the sound mode is explained by identifying it as the Goldstone mode associated with the spontaneous...

in this article, modeling and optimization of power consumption of two–stage compressed airsystem has been investigated. to do so, the two – stage compressed air cycle with intercooler offajr petroleum company was considered. this cycle includes two centrifugal compressors, ashell, and a tube intercooler. for modeling of power consumption, actual compressors isentropicefficiencies and intercool...