The main goal of this article is to study the oscillatory motion of a spherical gas bubble immersed in a Newtonian liquid subjected to a harmonic pressure excitation. We use the classical RayleighPlesset equation to study the radial motion of the bubble undergoing a forcing acoustic pressure field. The second order nonlinear ordinary differential equation that governs the bubble motion is solve...

The present study is performed to numerically analyze the growth of a vapor bubble during flow of water through a microchannel. The complete Navier– Stokes equations, along with continuity and energy equations, are solved using the SIMPLER (semi-implicit method for pressure-linked equations revised) method. The liquid–vapor interface is captured using the level set technique. The microchannel i...

We consider the effects of “photon bubble” shock trains on the vertical structure of radiation pressure-dominated accretion disks. These density inhomogeneities are expected to develop spontaneously in radiation-dominated accretion disks where magnetic pressure exceeds gas pressure, even in the presence of magnetorotational instability (MRI). They increase the rate at which radiation escapes fr...

This paper reports the first study of the O VI resonance line emission (λλ 1032, 1038) originating in the Local Bubble (or Local Hot Bubble) surrounding the solar neighborhood. In spite of the fact that O VI absorption within the Local Bubble has been observed, no resonance line emission was detected during our 230 ksec Far Ultraviolet Spectroscopic Explorer observation of a " shadowing " filam...

Accurate estimation of crude oil Bubble Point Pressure (Pb) plays a vital rule in the development cycle an field. point pressure is required many petroleum engineering calculations such as reserves estimation, material balance, reservoir simulation, production equipment design, and optimization well performance. Additionally, bubble key input parameter most property correlations. Thus, error es...

Bubble point pressure (BPP) is a key parameter for oil and gas reservoir identification, characterization, management. An accurate correlation of this property with the evolving digital technology machine learning, in absence experimental PVT analysis, serves as guidance development recovery fluids. In study, predictive BPP was derived by intrinsically linearizing nonlinear multiple regression,...

This paper presents a data acquisition system oriented to detect bubble collapse time and pressure losses in water cavitation in an internal orifice. An experimental campaign on a cavitating flow of water through an orifice has been performed to analyze the flow behavior at different pressures and temperatures. The experiments were based on visual observations and pressure fluctuations frequenc...

This second part of a two-part study explores the performance of a new cooling scheme in which the primary working fluid flowing through a micro-channel heat sink is indirectly cooled by a refrigeration cooling system. The objective of this part of study is to explore the pressure drop and heat transfer characteristics of the heat sink. During single-phase cooling, pressure drop decreased with ...

Models of spherical supersonic bubble implosion in cavitating liquids predict that it could generate temperatures and densities sufficient to drive thermonuclear fusion1,2. Convincing evidence for fusion is yet to be shown, but the transient conditions generated by acoustic cavitation are certainly extreme3–5. There is, however, a remarkable lack of observable data on the conditions created dur...

Bubble dynamics in water close to the tip of an ultrasonic horn (∼23 kHz, 3 mm diameter) have been studied using electrochemistry, luminescence, acoustics, light scattering, and high-speed imaging. It is found that, under the conditions employed, a large bubble cluster (∼1.5 mm radius) exists at the tip of the horn. This cluster collapses periodically every three to four cycles of the fundament...