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Related papers: Heating by Acoustic Waves of Multiphase Media

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A model for the generation of heat due to mechanical losses during acoustic wave propagation in a solid is considered in a Kelvin-Voigt type framework. In contrast to previous studies on related thermoviscoelastic models, in line with…

Analysis of PDEs · Mathematics 2024-11-25 Leander Claes , Johannes Lankeit , Michael Winkler

We present a linear stability analysis of the perturbation modes in anisotropic MHD flows with velocity shear and strong magnetic field. Collisionless or weakly collisional plasma is described within the 16-momentum MHD fluid closure model,…

Solar and Stellar Astrophysics · Physics 2015-12-09 E. S. Uchava , B. M. Shergelashvili , A. G. Tevzadze , S. Poedts

Acoustic waves are one of the primary suspects besides magnetic fields for the chromospheric heating process to temperatures above radiative equilibrium (RE). We derived the mechanical wave energy as seen in line-core velocities to obtain a…

Solar and Stellar Astrophysics · Physics 2015-05-13 C. Beck , E. Khomenko , R. Rezaei , M. Collados

We consider recent observations of the chromospheric network, and argue that the bright network grains observed in the Ca II H & K lines are heated by an as yet unidentified quasi-steady process. We propose that the heating is caused by…

Astrophysics · Physics 2009-11-13 S. S. Hasan , A. A. van Ballegooijen

Transverse magnetohydrodynamic (MHD) waves have been shown to be ubiquitous in the solar atmosphere and can in principle carry sufficient energy to generate and maintain the Sun's million-degree outer atmosphere or corona. However, direct…

Solar and Stellar Astrophysics · Physics 2015-08-19 Takenori J. Okamoto , Patrick Antolin , Bart De Pontieu , Han Uitenbroek , Tom Van Doorsselaere , Takaaki Yokoyama

High frequency acoustic waves have been suggested as a source of mechanical heating in the chromosphere. In this work the radial component of waves in the frequency interval 22mHz to 1mHz are investigated. Observations were performed using…

Astrophysics · Physics 2008-11-07 Aleksandra Andic

Controlling systems governed by partial differential equations is an inherently hard problem. Specifically, control of wave dynamics is challenging due to additional physical constraints and intrinsic properties of wave phenomena such as…

Signal Processing · Electrical Eng. & Systems 2023-12-18 Tristan Shah , Feruza Amirkulova , Stas Tiomkin

A new optical technique based on light-matter interaction is devised in-house to detect thermo-acoustic disturbances generated after ignition and during propagation of a premixed flame front in a half open channel. The technique involves…

Fluid Dynamics · Physics 2022-08-04 Ratan Joarder , Siba P. Choudhury , Syam S. , Nagendra Singh , S. K. Biswas

Outflowing winds of multiphase plasma have been proposed to regulate the buildup of galaxies, but key aspects of these outflows have not been probed with observations. Using ultraviolet absorption spectroscopy, we show that "warm-hot"…

A theoretical model of thermal boundary layers and acoustic heating in microscale acoustofluidic devices is presented. It includes effective boundary conditions allowing for simulations in three dimensions. The model is extended by an…

Fluid Dynamics · Physics 2021-12-21 Jonas Helboe Joergensen , Henrik Bruus

We study how different opacity-temperature scalings affect the dynamical evolution of irradiated gas clouds using time-dependent, radiation-hydrodynamics (rad-HD) simulations. When clouds are optically thick, the bright side heats up and…

High Energy Astrophysical Phenomena · Physics 2020-02-12 Sergei Dyda , Daniel Proga , Christopher S Reynolds

Much progress has been made recently in the acceleration of $\sim10^{4}$\,K clouds to explain absorption-line measurements of the circumgalactic medium and the warm, atomic phase of galactic winds. However, the origin of the cold, molecular…

Astrophysics of Galaxies · Physics 2021-12-08 Ryan Jeffrey Farber , Max Gronke

The radiative cooling of optically thin gaseous regions and the formation of a two-phase medium and of cold gas clouds with a clumpy substructure is investigated. In optically thin clouds, the growth rate of small isobaric density…

Astrophysics · Physics 2009-10-31 A. Burkert , D. N. C. Lin

We present observational constraints on the solar chromospheric heating contribution from acoustic waves with frequencies between 5 and 50 mHz. We utilize observations from the Dunn Solar Telescope in New Mexico complemented with…

Solar and Stellar Astrophysics · Physics 2021-11-03 Momchil E. Molnar , Kevin P. Reardon , Steven R. Cranmer , Adam F. Kowalski , Yi Chai , Dale Gary

The variation of an ionizing flux as a mechanism to stimulate the condensation of a diffuse gas is considered. To illustrate this effect, two situations are examined: one on the context of pregalactic conditions, and the other on the…

Astrophysics · Physics 2007-05-23 Antonio Parravano , Catherine Pech

We present a theoretical study of near-field heat transfer between two anisotropic materials separated by a small vacuum gap and maintained in a stationary non-equilibrium thermal situation. By combining standard stochastic electrodynamics…

Mesoscale and Nanoscale Physics · Physics 2011-09-07 Svend-Age Biehs , Philippe Ben-Abdallah , Felipe S. S. Rosa , Karl Joulain , Jean-Jacques Greffet

Evaporation of multicomponent droplets is important in a wide range of applications, albeit complex, and requires a careful investigation. We experimentally and numerically investigate the evaporation characteristics of spherical,…

Fluid Dynamics · Physics 2024-02-27 Yuki Wakata , Xing Chao , Chao Sun , Christian Diddens

Using semi-analytical, one-dimensional models, we elucidate the influence of scattering and absorption on the degree of Ohmic dissipation in hot Jovian atmospheres. With the assumption of Saha equilibrium, the variation in temperature is…

Earth and Planetary Astrophysics · Physics 2015-06-04 Kevin Heng

We present a theory for the acoustic force density acting on inhomogeneous fluids in acoustic fields on time scales that are slow compared to the acoustic oscillation period. The acoustic force density depends on gradients in the density…

Fluid Dynamics · Physics 2016-09-19 Jonas T. Karlsen , Per Augustsson , Henrik Bruus

Operating high-intensity discharge lamps in the high frequency range (20-300 kHz) provides energy-saving and cost reduction potentials. However, commercially available lamp drivers do not make use of this operating strategy because light…

Computational Physics · Physics 2016-12-21 Joerg Schwieger , Bernd Baumann , Marcus Wolff , Freddy Manders , Jos Suijker
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