scholarly journals Peculiarities of the behavior of the ionosphere and HF propagation parameters in September 2017

2018 ◽  
Author(s):  
Donat Blagoveshchensky ◽  
Olga Maltseva ◽  
Tatyana Nikitenko ◽  
Gennady Zhbankov
Keyword(s):  
Hf Propagation ◽  
Propagation Parameters

Updated climatological model predictions of ionospheric and HF propagation parameters

Radio Science ◽  
1991 ◽  
Vol 26 (4) ◽  
pp. 1017-1024 ◽  
Author(s):  
M. H. Reilly ◽  
F. J. Rhoads ◽  
J. M. Goodman ◽  
M. Singh
Keyword(s):  
Model Predictions ◽  
Hf Propagation ◽  
Propagation Parameters ◽  
Climatological Model

scholarly journals Assimilative modeling of ionospheric dynamics for nowcasting of HF propagation channels in the presence of TIDs

Radio Science ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 184-193 ◽  
Author(s):  
L. J. Nickisch ◽  
Sergey Fridman ◽  
Mark Hausman ◽  
Shawn Kraut ◽  
George Zunich
Keyword(s):  
Hf Propagation ◽  
Ionospheric Dynamics

Study on Application of Stress Wave for Nondestructive Test of Wood Defects

2013 ◽  
Vol 401-403 ◽  
pp. 1119-1123 ◽  
Author(s):  
Wen Shu Lin ◽  
Jin Zhuo Wu
Keyword(s):  
Nondestructive Test ◽  
Stress Wave ◽  
Significant Influence ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Wood Products ◽  
Propagation Time ◽  
Propagation Parameters ◽  
Wave Technique ◽  
Wooden Structures

The elm wood samples were tested by the technique of stress wave, and the testing results were analyzed by using the statistic software of SPSS. The results showed that the moister content of wood, wood crack, the sizes of holes and numbers of holes have significant influence on propagation parameters and dynamic modulus of elasticity. Under the same specifications, the propagation time of the stress wave was longer in the wood with holes or cracks than the perfect wood samples, and the time become longer with the increasing the sizes and numbers of holes or cracks. The studying results of the thesis will provide a sound background for the application of stress-wave technique in detecting the inner defects of wood products and other wooden structures.

Simulation of HF propagation and angle of arrival in a turbulent ionosphere

Radio Science ◽  
1989 ◽  
Vol 24 (2) ◽  
pp. 196-208 ◽  
Author(s):  
J.-F. Wagen ◽  
K. C. Yeh
Keyword(s):  
Angle Of Arrival ◽  
Hf Propagation

Numerical Simulation of Detonation Propagation in Flame Arrestor Applications

2020 ◽  
Author(s):  
Hoden A. Farah ◽  
Frank K. Lu ◽  
Jim L. Griffin
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Numerical Study ◽  
Forchheimer Equation ◽  
Detonation Propagation ◽  
Simulation Domain ◽  
Shock Transmission ◽  
Propagation Parameters ◽  
Porous Zone ◽  
Viscous Solutions

Abstract A detail numerical study of detonation propagation and interaction with a flame arrestor product was conducted. The simulation domain was based on the detonation flame arrestor validation test setup. The flame arrestor element was modeled as a porous zone using the Forchheimer equation. The coefficients of the Forchheimer equation were determined using experimental data. The Forchheimer equation was incorporated into the governing equations for axisymmetric reactive turbulent flow as a momentum sink. A 21-step elementary reaction mechanism with 10 species was used to model the stoichiometric oxyhydrogen detonation. Different cases of detonation propagation including inviscid, viscous adiabatic, and viscous with heat transfer and a porous zone were studied. A detail discussion of the detonation propagation and effect of the arrestor geometry, the heat transfer and the porous zone are presented. The inviscid numerical model solutions of the detonation propagation parameters are compared to one-dimensional analytical solution for verification. The viscous solutions are qualitatively compared to historical experimental data which shows very similar trend. The effect of the porous media parameters on shock transmission and re-initiation of detonation is presented.

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