An experimental study was conducted to characterize the transient behavior of laminar flow separation on a NASA low-speed GA (W)-1 airfoil at the chord Reynolds number of 70,000. In addition to measuring the surface pressure distribution around the airfoil, a high-resolution particle image velocimetry (PIV) system was used to make detailed flow field measurements to quantify the evolution of un...

The problem of predicting the moments of the distribution of bubble radius in bubbly flows is considered. The particular case where bubble oscillations occur due to a rapid (impulsive or step change) change in pressure is analyzed, and it is mathematically shown that in this case, inviscid bubble oscillations reach a stationary statistical equilibrium, whereby phase cancellations among bubbles ...

A theoretical model for bubble formation and weeping has been developed. Potential #ow theory is used to describe bubble formation at the ori"ce. The in#uence of detached, rising bubbles on liquid pressure at the ori"ce is predicted by Oseen's modi"cation to potential #ow. Model predictions of bubble volumes, weeping #ow rates and weep points agree well with experimental results. ( 2000 Elsevie...

The present study considers of the water and air flow and Micro-Bubble production inside the venturi tube, by the use of dimensional analysis. Numerical analysis of Micro-Bubble creation in venturi tube requires fast computers and large amounts of storage space. Up to now, there has been no numerical analysis concerning Micro-Bubble creation and all other existing studies are experimental. To s...

Bubble formation at two, three, four and six symmetrical ori&ces has been investigated by high-speed photography and analysis of chamber pressure 6uctuations. Regimes of synchronous, alternative and unsteady bubbling were clearly identi&ed, and the e7ects of ori&ce spacing and liquid depth on bubbling synchronicity and frequency were studied. Theoretical predictions of bubble frequency and aver...

We demonstrate extreme superheating and single bubble nucleation in an electrolyte solution within a nanopore in a thin silicon nitride membrane. The high temperatures are achieved by Joule heating from a highly focused ionic current induced to flow through the pore by modest voltage biases. Conductance, nucleation, and bubble evolution are monitored electronically and optically. Temperatures n...

We consider a quadrilateral ’mini’ finite element for approximating the solution of Stokes equations using a quadrilateral mesh. We use the standard bilinear finite element space enriched with element-wise defined bubble functions for the velocity and the standard bilinear finite element space for the pressure space. With a simple modification of the standard bubble function we show that a sing...

We propose and demonstrate a pressure sensor based on a micro air bubble at the end facet of a single mode fiber fusion spliced with a silica tube. When immersed into the liquid such as water, the air bubble essentially acts as a Fabry-Pérot interferometer cavity. Such a cavity can be compressed by the environmental pressure and the sensitivity obtained is >1000 nm/kPa, at least one order of ma...

1 Abstr~ct Dynamic nucleation of ice induced by a cavitation bubble in undercooked water is observed using an acoustic levitation technique. The observation indicates that a high pressure pulse associated with a collapsing bubble is indeed responsible for the nucleation of a high pressure phase of ice. Both the non-luminescing and Iuminescing cavitation bubbles require the minimum undercooking,...

In a certain parameter region, a single sonoluminescencing bubble is unstable against diffusion of gases and their chemical dissociation. Experiments show that a surface unstable bubble emits a microbubble and recoils. After this it exhibits specific dynamical features whereby the ambient radius changes in a nonmonotonic way. A numerical analysis identifies the phenomenon as the result of the i...