Acoustical characteristics of two-phase horizontal intermittent flow through an orifice

This study addresses acoustical characteristics, in particular, sound generation of intermittent flow regime in a horizontal pipe through an orifice, based on recorded pressure fluctuations and videos of upstream and downstream flow of the orifice. The flow regimes of interest are plug flow and slug flow, respectively, where sharp-edged and...

Mitigation of terrain induced slugging using mixer devices

The present work focuses on experimental evidence of slug mitigation via various devices. The slug mitigation potential of a number of mixers was tested using a laboratory scale air/water setup to compare their effect on the incoming slugs just upstream of the separator inlet. Dedicated methods and key performance indicators were developed to...

Effect of water-droplets on flow-induced pulsations in pipe with two closed-side branches: An experimental study

In this study experiments are conducted on the flow within a horizontal pipe with two closed side branches of equal length. This configuration is referred to as "quasi-cross configuration" as the distance between the two closed side branches is much smaller than the acoustic wavelength of the first acoustic mode. Focus is placed upon...

Hydrodynamic interaction between whistling axisymmetric cavities in the presence of a coupling longitudinal standing wave

An axisymmetric cavity along a pipe is a commonly encountered construction in industrial applications, which can also be considered as a unit element of a corrugated pipe. At critical conditions such a configuration causes severe noise problems, called whistling. Whistling is a self-sustained oscillation, driven by a flow-acoustic interaction....

Whistling behavior of periodic systems: Corrugated pipes and multiple side branch system

Whistling behavior of two geometrically periodic systems are investigated: corrugated pipes and a multiple side branch system. In both systems frequency (Helmholtz number) is a non-decreasing piecewise constant function of the Mach number, whose increase on average is approximately linear. The plateaus, lock-in frequencies, of this piecewise...

Modelling surface pressure fluctuation on medium-rise buildings

This paper describes the results of two experiments into the fluctuating characteristics of windinduced pressures on buildings in a built-up environment. The experiments have been carried out independently in Iceland and The Netherlands and can be considered to represent two separate cases of building geometries (HffiB and HoB). The results from...

Flow-induced noise around the a-pillar of an idealized car greenhouse

Due to the successes in reducing motor and tire noise as perceived inside cars and trucks, aerodynamically generated noise becomes more and more important. Some time ago the study of aero-acoustics in and around these vehicles was mainly done by wind tunnel test. Nowadays, computational methods become available that allow for numerical...

Prediction of wall-pressure fluctuations using the statistical approach to turbulence induced noise (Satin)

The noise prediction model SATIN (Statistical Approach to Turbulence /nduced Noise) is presented. SATIN assumes axial symmetric turbulence with the length scale ratio λ and the Reynolds stress ratio ξ as two anisotropy parameters. The model is based on Lighthill's acoustic analogy and allows to predict both the far-field noise radiation as well...