scholarly journals Stochastic discrete velocity averaging lemmas and Rosseland approximation

2016 ◽  
pp. 1-10
Author(s):  
Nathalie Ayi
Keyword(s):  
Discrete Velocity ◽  
Rosseland Approximation

Radiation Effect on the Mixed Convection Flow of a Viscoelastic Fluid Along an Inclined Stretching Sheet

2012 ◽  
Vol 67 (3-4) ◽  
pp. 195-202 ◽  
Author(s):  
Muhammad Qasim ◽  
Tasawar Hayat ◽  
Saleem Obaidat
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Viscoelastic Fluid ◽  
Radiative Heat ◽  
Heat Transfer Analysis ◽  
Convection Flow ◽  
Viscoelastic Parameter ◽  
Homotopy Analysis ◽  
Rosseland Approximation ◽  
Momentum Boundary Layer

This study concentrates on the heat transfer analysis of the steady flow of viscoelastic fluid along an inclined stretching surface. Analysis has been carried out in the presence of thermal radiation and the Rosseland approximation is used to describe the radiative heat flux in the energy equation. The equations of continuity, momentum and energy are reduced into the system of governing differential equations and solved by homotopy analysis method (HAM). The velocity and temperature are illustrated through graphs. Exact and homotopy solutions are compared in a limiting sense. It is noticed that viscoelastic parameter decreases the velocity and boundary layer thickness. It is also observed that increasing values of viscoelastic parameter reduces the thickness of momentum boundary layer and increase the heat transfer rate. However, it is found that increasing the radiation parameter has the effect of decreasing the local Nusselt number

scholarly journals Characterization of laser Doppler vibrometers using acousto-optic modulators

ACTA IMEKO ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 361
Author(s):  
Michael Gaitan ◽  
Jon Geist ◽  
Benjamin J. Reschovsky ◽  
Ako Chijioke
Keyword(s):  
Frequency Shift ◽  
Excitation Frequency ◽  
Laser Doppler Vibrometer ◽  
Laser Doppler ◽  
New Approach ◽  
Frequency Reference ◽  
Discrete Velocity ◽  
Velocity Shift ◽  
Vibration Excitation

We report on a new approach to characterize the performance of a laser Doppler vibrometer (LDV). The method uses two acousto-optic modulators (AOMs) to frequency shift the light from an LDV by a known quantity to create a synthetic velocity shift that is traceable to a frequency reference. Results are presented for discrete velocity shifts and for sinusoidal velocity shifts that would be equivalent to what would be observed in an ideal accelerometer vibration calibration. The method also enables the user to sweep the synthetic vibration excitation frequency to characterize the bandwidth of an LDV together with its associated electronics.

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