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1. Enrichment of Scavenged Particles in Jet Drops Determined by Bubble Size and Particle Position

   https://doi.org/10.1103/PhysRevLett.130.054001  

   Dubitsky, Lena; McRae, Oliver; Bird, James C. (February 2023, Physical Review Letters)
2. Oscillations of a partially wetting bubble

   https://doi.org/10.1017/jfm.2022.584  

   Ding, D.; Bostwick, J.B. (August 2022, Journal of Fluid Mechanics)

   We study the linear stability of a compressible sessile bubble in an ambient fluid that partially wets a planar solid support, where the gas is assumed to be an ideal gas that obeys the adiabatic law. The frequency spectrum is computed from an integrodifferential boundary value problem and depends upon the wetting conditions through the static contact angle $$\alpha$$ , the dimensionless equilibrium bubble pressure $$\varPi$$ , and the contact-line dynamics that we assume to be either (i) pinned or (ii) freely moving with fixed contact angle. Corresponding mode shapes are defined by the polar-azimuthal mode number pair $$[k,\ell ]$$ with $$k+\ell =\mathbb {Z}^{+}_{even}$$ . We report instabilities to the (i) $[0,0]$ breathing mode associated with volume change, and (ii) $[1,1]$ mode that is linked to horizontal centre-of-mass motion of the bubble. Stability diagrams and instability growth rates are computed, and the respective instability mechanisms are revealed through an energy analysis. The zonal $$\ell =0$$ modes are associated with volume change, and we show that there is a complex dependence between the classical volume and shape change modes for wetting conditions that differ from neutral wetting $$\alpha =90^\circ$$ . Finally, we show how the classical frequency degeneracy for the Rayleigh–Lamb modes of the free bubble splits for the azimuthal modes $$\ell \neq 0,1$$ . 

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3. Bubble deformation by a turbulent flow

   https://doi.org/10.1017/jfm.2021.379  

   Perrard, Stéphane; Rivière, Aliénor; Mostert, Wouter; Deike, Luc (August 2021, Journal of Fluid Mechanics)

   We investigate the modes of deformation of an initially spherical bubble immersed in a homogeneous and isotropic turbulent background flow. We perform direct numerical simulations of the two-phase incompressible Navier–Stokes equations, considering a low-density bubble in the high-density turbulent flow at various Weber numbers (the ratio of turbulent and surface tension forces) using the air–water density ratio. We discuss a theoretical framework for the bubble deformation in a turbulent flow using a spherical harmonic decomposition. We propose, for each mode of bubble deformation, a forcing term given by the statistics of velocity and pressure fluctuations, evaluated on a sphere of the same radius. This approach formally relates the bubble deformation and the background turbulent velocity fluctuations, in the limit of small deformations. The growth of the total surface deformation and of each individual mode is computed from the direct numerical simulations using an appropriate Voronoi decomposition of the bubble surface. We show that two successive temporal regimes occur: the first regime corresponds to deformations driven only by inertial forces, with the interface deformation growing linearly in time, in agreement with the model predictions, whereas the second regime results from a balance between inertial forces and surface tension. The transition time between the two regimes is given by the period of the first Rayleigh mode of bubble oscillation. We discuss how our approach can be used to relate the bubble lifetime to the turbulence statistics and eventually show that at high Weber numbers, bubble lifetime can be deduced from the statistics of turbulent fluctuations at the bubble scale. 

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4. A review on correlations of bubble growth mechanisms and bubble dynamics parameters in nucleate boiling

   https://doi.org/doi.org/10.1007/s10973-021-10876-2  

   Mahyar Ghazivini, Mazen Hafez (July 2022, Journal of thermal analysis and calorimetry)
5. Ultrasonic Bubble Cleaner as a Sustainable Solution

   https://doi.org/10.3390/fluids8110291  

   Howell, Justin; Ham, Emerson; Jung, Sunghwan (November 2023, Fluids)

   We aim to develop a floor-cleaning design by exploiting oscillating bubbles combined with ambient pressure waves to clean various surfaces. Previous studies of this method in lab settings have proven its efficacy, but practical applications, especially concerning real-world conditions like dirt surfaces, remain largely unprobed. Our findings indicate that, excluding a configuration with a heavy mass bottom transducer, all tested configurations achieved approximately 60–70% cleaning performance. A slight improvement in cleaning performance was observed with the introduction of microbubbles, although it was within the error margin. Particularly noteworthy is the substantial reduction in water consumption in configurations with a water pocket, decreasing from 280 mL to a mere 3 mL, marking a significant step toward more environmentally sustainable cleaning practices, such as reduced water usage. This research provides implications for real-world cleaning applications, promising an eco-friendly and efficient cleaning alternative that reduces water usage and handles a variety of materials without causing damage. 

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