High intensity pulsed ultrasound when interacting with microbubble contrast agents is potentially useful for biomedical applications such as drug delivery, cancer treatment and tissue ablation. To establish a fundamental understanding of the interaction between a microbubble with a sound wave, numerical simulations are performed using the Boundary Element Method (BEM). Bubble dynamics in terms ...

Prediction of jet noise is important for civil aircraft. Some CAA methodologies predict the full unsteady flow field of a jet in order to ascertain the far-field noise. The approach adopted here is to utilise CFD to obtain steady state information using a turbulence model and hence to provide inputs to a semi-empirical noise model, herein after referred to as the four source model. Predictions ...

In the collection and analysis of high-amplitude jet noise data for nonlinear acoustic propagation, both model-scale and full-scale measurements have limitations. Model-scale measurements performed in anechoic facilities are usually limited by transducer and data acquisition system bandwidths and maximum propagation distance. The accuracy of fullscale measurements performed outdoors is reduced ...

Experiments have characterized the acoustics of axisymmetric high-speed jets at a variety of Mach numbers and velocities and at pressure-matched, overexpanded, and underexpanded conditions. The effect of an annular secondary  ow on noise emission was also investigated.The fully expanded jet velocity ranged from 630 to 920m/s and the fully expanded jet Mach number ranged from 1.27 to 1.75.The s...

We present 3-D Large Eddy Simulation (LES) results for a turbulent Mach 0.9 isothermal round jet at a Reynolds number of 100,000 (based on jet nozzle exit conditions and nozzle diameter). Our LES code is part of a Computational Aeroacoustics (CAA) methodology that couples surface integral acoustics techniques such as Kirchhoff’s method and the Ffowcs Williams-Hawkings method with LES for the fa...

Abstract This paper presents a preliminary experimental investigation into the acoustics of two elliptical jet nozzles installed close to wing model. Acoustic pressure data is obtained for range observer polar angles mounted in far field jets. Three nominal Mach numbers, namely 0.4, 0.6 and 0.8 are studied. Results suggest that elliptic jets surveyed provide noise reduction jet-surface installa...

t-shape profile barriers are one of the most successful barriers among many different profiles. it has been shown that using welled diffusers on the top of t-shaped barriers makes a reactive barrier that shows better performance than that of any other used profile barriers compared with their equivalent absorbent barrier. the contribution of the top surface of reactive t-profile barriers to the...

This paper describes the experimental study of the noise generating characteristics of high-temperature, shock-containing jets emanating from conic-section, converging-diverging (C-D) nozzles. Conic C-D nozzles consist of two conic sections, one contracting and the other expanding, joined to form a supersonic nozzle with a very sharp radius of curvature at the nozzle throat. An experiment is co...