Dynamic pressure

About: Dynamic pressure is a research topic. Over the lifetime, 3496 publications have been published within this topic receiving 36148 citations. The topic is also known as: velocity pressure.

The Wave-Driven Ocean Circulation

Abstract: Oceanic surface gravity waves have a mean Lagrangian motion, the Stokes drift. The dynamics of winddriven, basin-scale oceanic currents in the presence of Stokes drift are modified by the addition of so-called vortex forces and wave-induced material advection, as well by wave-averaged effects in the surface boundary conditions for the dynamic pressure, sea level, and vertical velocity. Some theoretical analyses previously have been made for the gravity wave influences on boundary-layer motions, including the Ekman currents. The present paper extends this theory to the basin-scale, depth-integrated circulation in a bounded domain. It is shown that the Sverdrup circulation relation, with the meridional transport proportional to the curl of the surface wind stress, applies to Lagrangian transport, while the associated Eulerian transport is shown to have a component opposite to the Stokes-drift transport. A wave-induced correction to the relation between sea level and surface dynamic pressure is also derived. Preliminary assessments are made of the relative importance of these influences using a global wind climatology and an empirical relationship between the wind and wave fields. Recommendations are made for further development and testing of this theory and for its inclusion in general circulation models.

Wall Pressure and Shear Stress Spectra from Direct Simulations of Channel Flow

Abstract: Wall pressure and shear stress spectra from direct numerical simulations of turbulent plane channel flow are presented in this paper. Simulations have been carried out at a series of Reynolds numbers up to Re? = 1440, which corresponds to Re = 6:92 x 10(4) based on channel width and centerline velocity. Single-point and two-point statistics for velocity, pressure, and their derivatives have been collected, including velocity moments up to fourth order.§ The results have been used to study the Reynolds number dependence of wall pressure and shear stress spectra. It is found that the point spectrum of wall pressure collapses for Re? ? 360 under a mixed scaling for frequencies lower than the peak frequency of the frequency-weighted spectrum, and under viscous scaling for frequencies higher than the peak. Point spectra of wall shear stress components are found to collapse for Re? ? 360 under viscous scaling. The normalized mean square wall pressure increases linearly with the logarithm of Reynolds number. The rms wall shear stresses also increase with Reynolds number over the present range, but suggest some leveling off at high Reynolds number.

Dynamic pressure bearing device

Abstract: A dynamic pressure bearing device includes a rotary shaft, a dynamic pressure bearing member for supporting the rotary shaft, two radial dynamic pressure bearing parts and a thrust dynamic pressure bearing part formed between the dynamic pressure bearing member and the rotary shaft, and a lubricating fluid continuously filled in the two radial bearing parts and the thrust bearing part. A bypass passage for pressure release is provided for communicating across the two radial dynamic pressure bearing parts to flow the lubricating fluid corresponding to the amount of the unbalance caused by the unbalance of the pumping effect forces from a high-pressure side to a low-pressure side through the bypass passage to reduce the unbalance.

A velocity-pressure streamline diffusion finite element method for the incompressible Navier-Stokes equation

Abstract: A velocity pressure streamline diffusion finite element method for the incompressible Navier-Stokes equations