temperature waves
Recently Published Documents


TOTAL DOCUMENTS

113
(FIVE YEARS 17)

H-INDEX

14
(FIVE YEARS 1)

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Zhiwei Ding ◽  
Ke Chen ◽  
Bai Song ◽  
Jungwoo Shin ◽  
Alexei A. Maznev ◽  
...  

AbstractSecond sound refers to the phenomenon of heat propagation as temperature waves in the phonon hydrodynamic transport regime. We directly observe second sound in graphite at temperatures of over 200 K using a sub-picosecond transient grating technique. The experimentally determined dispersion relation of the thermal-wave velocity increases with decreasing grating period, consistent with first-principles-based solution of the Peierls-Boltzmann transport equation. Through simulation, we reveal this increase as a result of thermal zero sound—the thermal waves due to ballistic phonons. Our experimental findings are well explained with the interplay among three groups of phonons: ballistic, diffusive, and hydrodynamic phonons. Our ab initio calculations further predict a large isotope effect on the properties of thermal waves and the existence of second sound at room temperature in isotopically pure graphite.


2022 ◽  
Vol 962 (1) ◽  
pp. 012019
Author(s):  
S Ye Kholodovskii

Abstract The article indicates the relevance of the study of heat transfer processes in kurums. Boundary value problems of vertical temperature change in kurums and in the underlying rock base are solved, when the temperature on the surface of kurums changes according to a given periodic law, which simulates daily and seasonal temperature fluctuations. The cases when the rock base is a heat-conducting medium and permafrost are considered. Some regularities of temperature propagation along the depth are revealed.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Giacomo Mazza ◽  
Marco Gandolfi ◽  
Massimo Capone ◽  
Francesco Banfi ◽  
Claudio Giannetti

AbstractUnderstanding the mechanism of heat transfer in nanoscale devices remains one of the greatest intellectual challenges in the field of thermal dynamics, by far the most relevant under an applicative standpoint. When thermal dynamics is confined to the nanoscale, the characteristic timescales become ultrafast, engendering the failure of the common description of energy propagation and paving the way to unconventional phenomena such as wave-like temperature propagation. Here, we explore layered strongly correlated materials as a platform to identify and control unconventional electronic heat transfer phenomena. We demonstrate that these systems can be tailored to sustain a wide spectrum of electronic heat transport regimes, ranging from ballistic, to hydrodynamic all the way to diffusive. Within the hydrodynamic regime, wave-like temperature oscillations are predicted up to room temperature. The interaction strength can be exploited as a knob to control the dynamics of temperature waves as well as the onset of different thermal transport regimes.


2021 ◽  
Vol 24 (2) ◽  
pp. 13-21
Author(s):  
Anatoly M. Afanasyev ◽  
Yulia S. Bakhracheva

The problem of asymptotic fluctuations of temperature and moisture content in a half-space whose boundary is blown by an air flow with a temperature varying according to the harmonic law is solved by the method of complex amplitudes. The material filling the half-space consists of a solid base (capillary-porous body) and water. The well-known Fourier solution for temperature fluctuations in half-space in the absence of moisture and under the boundary conditions of heat exchange ofthefirst kind is generalized to the case of a wet material under the boundary conditions of Newton for temperature and Dalton for moisture content. The results of the work can be used in geocryology to model seasonal changes in the thermophysical state offrozen rocks and soils, in the theory of building structures to study the thermal regime of indoor premises with fluctuations in ambient temperature, in the theory of drying by electromagnetic radiation to study the processes of heat and mass transfer inoscillating modes.


Author(s):  
Marco Gandolfi ◽  
Claudio Giannetti ◽  
Francesco Banfi
Keyword(s):  

2021 ◽  
Vol 23 ◽  
pp. 100926
Author(s):  
Zeren Zhang ◽  
Liujun Xu ◽  
Xiaoping Ouyang ◽  
Jiping Huang
Keyword(s):  

2021 ◽  
Vol 7 (27) ◽  
pp. eabg4677
Author(s):  
Albert Beardo ◽  
Miquel López-Suárez ◽  
Luis Alberto Pérez ◽  
Lluc Sendra ◽  
Maria Isabel Alonso ◽  
...  

Second sound is known as the thermal transport regime where heat is carried by temperature waves. Its experimental observation was previously restricted to a small number of materials, usually in rather narrow temperature windows. We show that it is possible to overcome these limitations by driving the system with a rapidly varying temperature field. High-frequency second sound is demonstrated in bulk natural Ge between 7 K and room temperature by studying the phase lag of the thermal response under a harmonic high-frequency external thermal excitation and addressing the relaxation time and the propagation velocity of the heat waves. These results provide a route to investigate the potential of wave-like heat transport in almost any material, opening opportunities to control heat through its oscillatory nature.


Sign in / Sign up

Export Citation Format

Share Document