Proposed control equipment scheme is based on acoustic Helmholtz resonator property to change its resonance frequency when sound speed in the vicinity of its throat inlet is changed. So this kind of resonator with pressure measuring acoustic transducer is installed in well known Pitou probe static pressure volume envelope, slightly changing its construction. To use Pitou probe of new type, exce...

This paper (SPE 134140) was accepted for presentation at the SPE Annual Technical Conference and Exhibition, Florence, Italy, 19–22 September 2010, and revised for publication. Original manuscript received 1 June 2010. Revised manuscript received 20 October 2010. Paper peer approved 8 November 2010. Summary The second-largest oil spillage in Norwegian petroleum history occurred on 12 December 2...

A theoretical study analyzing three-dimensional combustion acoustic instabilities in a liquid propellant rocket engine combustor has been conducted. A linear theory based on Crocco’s pressure sensitive time lag model is used. To apply this theory the combustor is divided into two main components, including the combustion chamber and the converging part of the nozzle. The assumption of concentra...

The paper considers receiving acoustic horns designed for particle velocity amplification and suitable for use in vector sensing applications. Unlike conventional horns, designed for acoustic pressure amplification, acoustic velocity horns (AVHs) deliver significant velocity amplification even when the overall size of the horn is much less than an acoustic wavelength. An AVH requires an open-en...

This study explores the use of scanning acoustic microscopy (SAM) as a potential tool for characterisation of arterial stiffness using aortic biopsies. SAM data is presented for human tissue collected during aortic bypass graft surgery for multi-vessel coronary artery disease. Acoustic wave speed as determined by SAM was compared to clinical data for the patients namely, pulse wave velocity (PW...

We present a novel approach for optimizing acoustic parameters using sensitivity analysis for computer-aided design and analysis of architectural models. Our approach builds on recent low-dispersion wave-based acoustic solvers that can accurately compute the pressure field in large models. We present an efficient technique to compute the gradient of the pressure field using automatic differenti...

Time-periodic CFD simulations are widely used to investigate turbomachinery components. The triple-plane pressure mode matching method (TPP) developed by Ovenden and Rienstra extracts the acoustic part in such simulations. Experience shows that this method is subject to significant errors when the amplitude of pseudo-sound is high compared to sound. Pseudo-sound are unsteady pressure fluctuatio...

the current study presents the results of the aerodynamic noise prediction of the flow field around a naca 0012 airfoil at a chord-based reynolds number of 100,000 and at 8.4 degree angle of attack. an incompressible large eddy simulation (les) turbulence model is applied to obtain the instantaneous turbulent flow field. the noise prediction is performed by the ffowcs williams and hawkings (fw-...

Fluid pressure increase in the brain, contained in the skull, is a serious medical condition that can be life threatening. Intracranial pressure changes can be detected noninvasively using acoustic stimulation and analysis. The brain and eye are coupled resonant systems that will respond in a predictable fashion to brain pressure increases, given the constraints of the bioboundary (skull) condi...

The effects of pressure on the structure of ice XI-an ordered form of the phase of ice Ih, which is known to amorphize under pressure-are investigated theoretically using density-functional theory. We find that pressure induces a mechanical instability, which is initiated by the softening of an acoustic phonon occurring at an incommensurate wavelength, followed by the collapse of the entire aco...