Hydrostatic equilibrium

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

Parametrization design based hydrostatic pressure spindle manufacturing method

Abstract: The invention relates to a parametrization design based hydrostatic pressure spindle manufacturing method, belongs to the technical field of hydrostatic pressure spindles and solves the problems of low manufacturing efficiency of an existing hydrostatic pressure spindle and large difference between prediction of spindle cutting stability and practical results during computing. The parametrization design based hydrostatic pressure spindle manufacturing method includes firstly, establishing a parametrization finite element model of a hydrostatic pressure spindle; presetting initial values of structural parameters of the hydrostatic pressure spindle; performing numerical simulation of hydrostatic bearing carrying characteristics of the liquid hydrostatic spindle and obtaining bearing rigidity matrix and bearing temperature rise of a static pressure bearing of the liquid hydrostatic pressure spindle; computing dynamic parameters of the liquid hydrostatic pressure spindle and spindle dynamic characteristics with vortex effect; obtaining critical cutting thickness of the spindle; outputting the data via a man-machine interactive interface when the above results meet the manufacturing requirements of the spindle, and realizing manufacturing of the hydrostatic pressure spindle. The parametrization design based hydrostatic pressure spindle manufacturing method is used for manufacturing the hydrostatic pressure spindle.

Flow Criterion Research on Fluid in Hydrostatic Bearing from Laminar to Turbulent Transition

Abstract: The multi- pad circular guide hydrostatic bearing of heavy-duty CNC machine is taken as the research object. Based on the lubrication properties of the heavy hydrostatic bearing, viscosity-temperature equation of interstitial fluid is established in various viscosities. In accordance with factory actual production, the fluid critical from laminar to turbulent is calculated by finite volume method. The inner flow field of hydrostatic bearing is simulated, when the rotating speed of workbench is 6r/min at different flow. The simulation results reveal flow distribution low and verify the reliability of the calculation. The results show that, the transition critical inlet fluid flow from laminar to turbulent of fluid in hydrostatic bearing is 22L/min. Through the above analysis and research, reveals the flow rule of the hydrostatic bearing oil film bearing gap, provides a theoretical basis for actual hydrostatic bearing for engineering structural optimization design.

Earth’s gravity from space

Abstract: Satellite gravimetry began with the launch of the satellites Sputnik 1 and 2 in 1957. During the following 43 years, more and more details were discovered and the models of the Earth’s gravity could be refined. Methods improved and more and more satellite orbits and ground stations were added in the analysis, employing more advanced and precise measuring techniques. A new era started with the dedicated gravimetry missions CHAMP (2000–2010), GRACE (2002–2017), and GOCE (2009–2013). The methods of satellite-to-satellite tracking and satellite gradiometry resulted in a substantial improvement of our knowledge of the Earth’s gravity field in terms of accuracy and its spatial and temporal variations. There are three basic ways of using gravity and geoid models in Earth sciences and geodesy. First, in solid Earth physics, the highs and lows of the field are investigated in comparison with an idealized Earth, e.g., a hydrostatic equilibrium figure. In particular, in South America, Africa, Himalaya and Antarctica the gravity field is known much better now, due to GOCE and lead to an improved understanding of the continental crust and lithosphere. Second, in oceanography, the geoid serves as surface in equilibrium, a hypothetical ocean at rest. The ocean topography is the deviation of the actual ocean surface, measured by satellite altimetry, from this reference. The ocean topography serves as a new and independent input to ocean circulation modeling and leads to an improved understanding of ocean transport of mass, heat, and nutrients. Similarly, geodetic heights of the land surface will soon be referred to the geoid, leading to globally consistent heights and enabling the removal of existent systematic deformations and offsets of national and continental height systems. Third, the GRACE time series of monthly gravity models, reflecting seasonal, inter-annual and long-term gravity changes, became one of the most valuable data sources of climate change studies.

Mountain Waves Produced by a Stratified Boundary Layer Flow. Part I: Hydrostatic Case

Abstract: A hydrostatic theory for mountain waves with a boundary layer of constant eddy viscosity is presented. It predicts that dissipation impacts the dynamics over an inner layer whose depth is c...