Low swirl premixed methane-air flame dynamics under acoustic excitations

2019 ◽  
Vol 31 (9) ◽  
pp. 095106 ◽  
Author(s):  
M. Shahsavari ◽  
M. Farshchi ◽  
S. R. Chakravarthy ◽  
A. Chakraborty ◽  
I. B. Aravind
Keyword(s):  
Flame Dynamics ◽  
Acoustic Excitations

scholarly journals Thermal acoustic excitations with atomic-scale wavelengths in amorphous silicon

2019 ◽  
Vol 3 (6) ◽  
Author(s):  
Jaeyun Moon ◽  
Raphaël P. Hermann ◽  
Michael E. Manley ◽  
Ahmet Alatas ◽  
Ayman H. Said ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Atomic Scale ◽  
Acoustic Excitations

Impingement Cooling Flow and Heat Transfer Under Acoustic Excitations

1997 ◽  
Vol 119 (4) ◽  
pp. 810-817 ◽  
Author(s):  
C. Gau ◽  
W. Y. Sheu ◽  
C. H. Shen
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Shear Layer ◽  
Turbulence Intensity ◽  
Pressure Level ◽  
Unstable Wave ◽  
Impingement Cooling ◽  
Cooling Flow ◽  
Acoustic Excitations ◽  
Excitation Pressure

Experiments are performed to study (a) slot air jet impingement cooling flow and (b) the heat transfer under acoustic excitations. Both flow visualization and spectral energy evolution measurements along the shear layer are made. The acoustic excitation at either inherent or noninherent frequencies can make the upstream shift for both the most unstable waves and the resulting vortex formation and its subsequent pairing processes. At inherent frequencies the most unstable wave can be amplified, which increases the turbulence intensity in both the shear layer and the core and enhances the heat transfer. Both the turbulence intensity and the heat transfer increase with increasing excitation pressure levels Spl until partial breakdown of the vortex occurs. At noninherent frequencies, however, the most unstable wave can be suppressed, which reduces the turbulence intensity and decreases the heat transfer. Both the turbulence intensity and the heat transfer decreases with increasing Spl, but increases with increasing Spl when the excitation frequency becomes dominant. For excitation at high Reynolds number with either inherent or noninherent frequency, a greater excitation pressure level is needed to cause the enhancement or the reduction in heat transfer. During the experiments, the inherent frequencies selected for excitation are Fo/2 and Fo/4, the noninherent frequencies are 0.71 Fo, 0.75 Fo, and 0.8 Fo, the acoustic pressure level varies from 70 dB to 100 dB, and the Reynolds number varies from 5500 to 22,000.

Structural evolution and acoustic phonon behavior in crystalline PTFE latex films

2003 ◽  
Vol 779 ◽  
Author(s):  
M. Pierno ◽  
C.S. Casari ◽  
A. Li Bassi ◽  
M.G. Beghi ◽  
R. Piazza ◽  
...  
Keyword(s):  
Structural Evolution ◽  
Crystalline Polymer ◽  
Model Systems ◽  
Fibrillar Structure ◽  
Sintering Process ◽  
Latex Films ◽  
Force Microscopy ◽  
Crystalline Polymers ◽  
Atomic Force ◽  
Acoustic Excitations

AbstractThe structural evolution of polytetrafluoroethylene (PTFE) crystalline polymer latex films is studied at hundreds nanometer length scale by atomic force microscopy and Brillouin light scattering. In a controlled sintering process the transition is observed from the original particle distribution towards a ‘fibrillar’ structure of crystalline regions embedded in a disordered matrix. This transition is accompanied by a cross-over from localized acoustic excitations to propagating acoustic phonons, related to mesoscopic elastic properties. After sintering, a ‘mark’ of the original particulate structure persists, suggesting that filming of crystalline polymers may be analogous to sintering of ceramic powders. Films of crystalline polymers can thus be exploited as model systems to study the elasto-optical properties of granular and disordered media.

Simple Analysis of Flame Dynamics via Flexible Convected Disturbance Models

2012 ◽  
Vol 28 (6) ◽  
pp. 1268-1276 ◽  
Author(s):  
Joseph A. Ranalli ◽  
Donald Ferguson ◽  
Christopher Martin
Keyword(s):  
Simple Analysis ◽  
Flame Dynamics

Pore-scale flame dynamics in a one-layer porous burner

2021 ◽  
pp. 111711
Author(s):  
Roman V. Fursenko ◽  
Igor A. Yakovlev ◽  
Egor S. Odintsov ◽  
Sergey D. Zambalov ◽  
Sergey S. Minaev
Keyword(s):  
Pore Scale ◽  
Flame Dynamics ◽  
Porous Burner
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