When fluid flows through the underwater vehicles, flow separation occurs, and generates eddy currents, which in turn induce pulsating pressure on surfaces of generating noise making vehicle easy to expose. We conducted research this phenomenon, taking cone-column shell as object based Large Eddy Simulation (LES) theory. Additionally, calculation results each parameter such grid scale structural...

An inherent problem of single-phase rectifiers is the existence of a pulsating portion in the input power, which pulsates at twice the grid frequency. If this pulsating power is transferred to the DC-link, it causes a significant amount of second-order harmonic at the output voltage. Since in many applications, such a high level of DC oscillation is not acceptable, so the pulsating power must b...

Oxygen gas-liquid mass transfer coefficient was measured in a gas-induced pulsating flow bubble column. Pulsating amplitude had a great influence on kla under pulsating state of equal base flow and pulsating flow, which was enhanced up to 30 % compared with that under steady state; however, it had a negative effect on mass transfer under a fixed low base flow. It was also found that kla had a n...

In this paper, we prove the uniqueness, up to shifts, of pulsating traveling fronts for reaction-diffusion equations in periodic media with Kolmogorov-Petrovsky-Piskunov type nonlinearities. These results provide in particular a complete classification of all KPP pulsating fronts. Furthermore, in the more general case of monostable nonlinearities, we also derive several global stability propert...

BACKGROUND To assess the reproducibility of ophthalmodynamometric measurements using a new, Goldmann contact lens associated, device allowing biomicroscopic visualisation of the optic disc. METHODS The prospective clinical study included 87 eyes of 58 subjects presenting with a normal fundus (n=40), or ocular diseases (n=47). With topical anaesthesia, a Goldmann contact lens, fitted with a pr...

Motivated by recent event studies and modeling efforts on pulsating aurora, which conclude that the precipitation energy during these events is high enough to cause significant chemical changes in the mesosphere, this study looks for the bulk behavior of auroral pulsations. Based on about 400 pulsating aurora events, we outline the typical duration, geomagnetic conditions, and change in the pea...

Prediction of pressure pulsation magnitude and their harmonic components for a multistage reciprocating compressor, piping and reservoir system depends on the input design and operating parameters. In the present paper, the results of the theoretical study carried out to study the effect of such parameters on pressure pulsations and their harmonics have been presented. The effect of pipe diamet...

The chemical-gas dynamic mechanisms behind the instability and failure of a onedimensional pulsating detonation wave driven by a three-step chain-branching reaction are revealed by direct numerical simulation. Two types of pulsating instability observed experimentally are explained. The first involves regular oscillations of the detonation front, where the instability is driven by low-frequency...

The channel flow subjected to a wind stress at the free surface and an oscillating pressure gradient is investigated using large-eddy simulations. The orientation of the surface stress is parallel with the oscillating pressure gradient and a purely pulsating mean flow develops. The Reynolds number is typically Re!=10 and the Keulegan–Carpenter number—the ratio between the oscillation period and...

Pressure sensitive paint (PSP) was used to measure pressure on the blades of a radial compressor with a 51 mm inlet diameter rotating at speeds up to 50 krpm using the so called lifetime method. A diode laser with a scanning-mirror system was used to illuminate the paint and the luminescent lifetime was registered using a photo multiplier. With the described technique the surface-pressure field...