Modeling acoustic cavitation with inhomogeneous polydisperse bubble population on a large scale.

A model for acoustic cavitation flows able to depict large geometries and time scales is proposed. It is based on the Euler-Lagrange approach incorporating a novel Helmholtz solver with a non-linear acoustic attenuation model. The method is able to depict a polydisperse bubble population, which may vary locally.

Soft Viscoelastic Particles in Contact with a Quartz Crystal Microbalance (QCM): A Frequency-Domain Lattice Boltzmann Simulation.

Shifts of frequency and bandwidth of a quartz crystal microbalance (QCM) in contact with a structured, viscoelastic sample have been computed with a linearized version of the lattice Boltzmann method (LBM). The algorithm operates in the frequency domain and covers viscoelasticity. The different domains are characterized by different values of the complex viscosity, η, equivalent to different values of the shear modulus, .

Bubble size measurements in different acoustic cavitation structures: Filaments, clusters, and the acoustically cavitated jet.

Acoustic cavitation typically forms a variety of bubble structures of generally unknown and broad size distributions. As the bubbles strongly oscillate, their (equilibrium) sizes are not directly observable. Here, a method is presented to experimentally determine the size distribution in bubble populations from high-speed imaging of the bubbles in oscillation.

Frequency Shifts of a Quartz Crystal Microbalance Calculated with the Frequency-Domain Lattice-Boltzmann Method: Application to Coupled Liquid Mass.

In recent years the quartz crystal microbalance (QCM) has seen an impressive evolution from a film-thickness monitor to a surface-analytical instrument with capabilities much beyond gravimetry. In particular, the instrument has often been applied to adsorbates from a liquid phase and, also, to samples with structure in the surface plane. In order to quantitatively predict frequency shifts induced by such samples from a model, one needs to compute the in-phase component of the area-averaged periodic tangential stress at the resonator surface.

An Euler-Lagrange method considering bubble radial dynamics for modeling sonochemical reactors.

Unsteady numerical computations are performed to investigate the flow field, wave propagation and the structure of bubbles in sonochemical reactors. The turbulent flow field is simulated using a two-equation Reynolds-Averaged Navier-Stokes (RANS) model. The distribution of the acoustic pressure is solved based on the Helmholtz equation using a finite volume method (FVM).

Dissipation of ultrasonic wave propagation in bubbly liquids considering the effect of compressibility to the first order of acoustical Mach number.

In this paper, the energy conservation approach presented by Louisnard (2010) [1] for bubbly liquid is modified by applying the Keller-Miksis Equation (KME) on the radial dynamics of cavitation bubbles. As the sound wave is damped through the liquid due to thermal, viscous and radiation effects, it cannot propagate over long distances. With the use of the Rayleigh-Plesset Equation (RPE) in the energy conservation approach, the part of the damping due to the acoustic radiation is neglected.

Influence of walls on the migration of non-Brownian spherical particles in creeping flow: a lattice Boltzmann study.

The influence of walls on binary encounters of spherical particles under creeping flow is studied by means of the lattice Boltzmann method. Depending on the initial particle displacement different behaviours can be observed, including the 'swapping' trajectories. The domain of the swapping trajectories is identified for interacting spheres with the same diameter; some preliminary results are given for the case of two spheres with different diameters.

Analysis of the flow field and pressure drop in fixed-bed reactors with the help of lattice Boltzmann simulations.

The pressure drop of technical devices is a crucial property for their design and operation. In this paper, we show how the results of lattice Boltzmann simulations can be used in science and engineering to improve the physical understanding of the pressure drop and the flow inhomogeneities in porous media, especially in sphere-packed fixed-bed reactors with low aspect ratios. Commonly used pressure drop correlations are based on simplified assumptions such as the capillary or tortuosity model, which do not reflect all hydrodynamic effects.