Hydrostatic equilibrium

About: Hydrostatic equilibrium is a research topic. Over the lifetime, 2451 publications have been published within this topic receiving 62172 citations.

Effect of hydrostatic initial stress on a fiber-reinforced thermoelastic medium with fractional derivative heat transfer

Abstract: Purpose – The purpose of this paper is to investigate the influences of fractional order, hydrostatic initial stress and gravity field on the plane waves in a linearly fiber-reinforced isotropic thermoelastic medium. Design/methodology/approach – The problem has been solved analytically and numerically by using the normal mode analysis. Findings – Numerical results for the temperature, the displacement components and the stress components are presented graphically and analyzed the results. The graphical results indicate that the effect of fractional order, hydrostatic initial stress and gravity field on the plane waves in the fiber-reinforced thermoelastic medium are very pronounced. Comparisons are made with the results in the absence and presence of hydrostatic initial stress and gravity field. Originality/value – In the present work, the authors shall formulate a fiber-reinforced two-dimensional problem under the effect of fractional order, hydrostatic initial stress, and gravity field. The normal mode...

Numerical studies of wind forced internal waves with a nonhydrostatic model

Abstract: The nonhydrostatic pressure effects on the generation and propagation of wind-forced internal waves are studied with a two-dimensional numerical ocean model. A one-way directed wind pulse over a stratified ocean initiates surface and internal waves in a closed basin. The studies are performed with horizontal grid sizes in the range from 1 km to 62.5 m. The experiments are performed with both a hydrostatic and a nonhydrostatic model, facilitating systematic studies of the sensitivity of the numerical model results to the grid size and to the nonhydrostatic pressure adjustments. The results show that the nonhydrostatic pressure effects are highly dependent on the grid size and grow with increased resolution. In the internal depression wave, the horizontal nonhydrostatic pressure gradients reach the same order of magnitude as the hydrostatic gradients in the high-resolution nonhydrostatic studies. In these studies, the nonhydrostatic pressure gradients approximately balance the corresponding hydrostatic pressure gradients in the internal depression wave, and the wave degenerates into a train of soliton waves. The time for the soliton form to develop agrees with the steepening timescale calculated from Korteweg-de Vries theory. In the high-resolution hydrostatic model, the internal depression wave takes the form of a single wave front. When the internal waves are generated in the boundary layers, the nonhydrostatic pressure gradients are much smaller than the hydrostatic gradients and the generation processes are not effected by the nonhydrostatic pressure with the present range of grid sizes.

The influence of low-degree p-mode frequencies on the determination of the structure of the solar interior

Abstract: Accurate measurements of the frequencies of low-degree acoustic oscillations provide valuable information about the structure of the solar core. We determine the radial resolution that can be achieved by direct inversions of frequency data sets recently obtained by various observers to find the hydrostatic parameters density, sound speed and a parameter of convective stability. The outcome of those inversions indicates that the outer part of the radiative zone of the Sun is similar to that of a solar model that takes account of helium settling against microscopic diffusion. from the two data sets with lowest estimated errors (those by Toutain & Frohlich and Anguera Gubau et al.) there is some evidence for an error in the modelling of the energy-generating core, which could be accounted for by local material redistribution in the core

Nonaxisymmetric incompressible hydrostatic pressure effects in radial face seals

Abstract: A flat seal having an angular misalinement is analyzed, taking into account the radial variations in seal clearance. An analytical solution for axial force, tilting moment, and leakage is presented that covers the whole range from zero to full angular misalinement. Nonaxisymmetric hydrostatic pressures due to the radial variations in the film thickness have a considerable effect on seal stability. When the high pressure is on the outer periphery of the seal, both the axial force and the tilting moment are nonrestoring. The case of high-pressure seals where cavitation is eliminated is discussed, and the possibility of dynamic instability is pointed out.