Chemical laser grating selection measurements of initial vibrational energy distribution by reactions of F atoms with H2, CH4, C2H6

1988 ◽  
Vol 88 (4) ◽  
pp. 2379-2392 ◽  
Author(s):  
Shaoping Lu ◽  
Chengshan Liu ◽  
Xuefeng Yang ◽  
Kaiba Li ◽  
Yukun Gu ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Vibrational Energy ◽  
Chemical Laser ◽  
Vibrational Energy Distribution

Vibrational energy distribution in plate excited with random white noise

2021 ◽  
Vol 263 (6) ◽  
pp. 965-969
Author(s):  
Tyrode Victor ◽  
Nicolas Totaro ◽  
Laurent Maxit ◽  
Alain Le Bot
Keyword(s):  
Boundary Conditions ◽  
Energy Distribution ◽  
White Noise ◽  
Numerical Simulations ◽  
Ray Tracing ◽  
Energy Analysis ◽  
Vibrational Energy ◽  
Statistical Energy Analysis ◽  
Vibrational Energy Distribution ◽  
Tracing Method

In Statistical Energy Analysis (SEA) and more generally in all statistical theories of sound and vibration, the establishment of diffuse field in subsystems is one of the most important assumption. Diffuse field is a special state of vibration for which the vibrational energy is homogeneously and isotropically distributed. For subsystems excited with a random white noise, the vibration tends to become diffuse when the number of modes is large and the damping sufficiently light. However even under these conditions, the so-called coherent backscattering enhancement (CBE) observed for certain symmetric subsystems may impede diffusivity. In this study, CBE is observed numerically and experimentally for various geometries of subsystem. Also, it is shown that asymmetric boundary conditions leads to reduce or even vanish the CBE. Theoretical and numerical simulations with the ray tracing method are provided to support the discussion.

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