Nearfield Aerodynamics and Optical Propagation Characteristics of a Large-Scale Turret Model

1982 ◽  
Author(s):  
William C. Rose ◽  
James E. Craig ◽  
K. R. Raman
Keyword(s):  
Large Scale ◽  
Propagation Characteristics ◽  
Optical Propagation

scholarly journals Physical Modelling of Roll and Pitch Motions of Travelling or Stationary Ship in Large-Scale Landslide-Generated Waves

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Pei-yin Yuan ◽  
Ping-yi Wang ◽  
Yu Zhao
Keyword(s):  
Large Scale ◽  
Physical Modelling ◽  
River Channel ◽  
Mountain River ◽  
Propagation Characteristics ◽  
Field Investigations ◽  
Movement Characteristics ◽  
Depth Study ◽  
Sailing Ship ◽  
River Type

Large-scale landslides often occur in river-type reservoirs, and landslide-generated waves affect navigation channels and the navigation of ships. Thus, such waves cause widespread regional disasters. This study establishes a mechanical model of landslide-generated waves via field investigations and data collection, reveals the mechanism and process of landslide-generated waves, and investigates the propagation characteristics of landslide-generated waves along a sloping wave. The feasibility of the model is verified via (i) regularity analysis, (ii) comparative analysis of the effect of landslide-generated waves of mountain river channel reservoirs on the movement characteristics of navigation vessels and stationary vessels, (iii) deviation from the equilibrium position, and (iv) an in-depth study of the influence of large-scale landslide-generated waves on ships in different navigation positions in a river channel. Countermeasures are proposed for a sailing ship to tackle a sudden landslide-generated wave; these measures can provide a theoretical basis for ships to sail safely through large-scale landslide-generated waves.

scholarly journals Effects of Concrete on Propagation Characteristics of Guided Wave in Steel Bar Embedded in Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Zhupeng Zheng ◽  
Ying Lei
Keyword(s):  
Large Scale ◽  
Guided Waves ◽  
Density Ratio ◽  
Guided Wave ◽  
Wave Number ◽  
Propagation Characteristics ◽  
Civil Infrastructures ◽  
Steel Bar ◽  
Reinforced Concrete Member ◽  
Steel Bars

Techniques based on ultrasonic guided waves (UGWs) play important roles in the structural health monitoring (SHM) of large-scale civil infrastructures. In this paper, dispersion equations of longitudinal wave propagation in reinforced concrete member are investigated for the purpose of monitoring steels embedded in concrete. For a steel bar embedded in concrete, not the velocity but the attenuation dispersion curves will be affected by the concrete. The effects of steel-to-concrete shear modulus ratio, density ratio, and Poisson’s ratio on propagation characteristics of guided wave in steel bar embedded in concrete were studied by the analysis of the real and imaginary parts of the wave number. The attenuation characteristics of guided waves of steel bar in different conditions including different bar concrete constraint and different diameter of steel bar are also analyzed. Studies of the influence of concrete on propagation characteristics of guided wave in steel bars embedded in concrete will increase the accuracy in judging the structure integrity and promote the level of defect detection for the steel bars embedded in concrete.

Large-scale FDTD analysis to obtain precise propagation characteristics of in-flight wireless access service

2013 Africon ◽  
2013 ◽  
Author(s):  
Takashi Hikage ◽  
Toshio Nojima ◽  
Shunichi Futatsumori ◽  
Akiko Kohmura ◽  
Naruto Yonemoto
Keyword(s):  
Large Scale ◽  
Wireless Access ◽  
Propagation Characteristics ◽  
Access Service

scholarly journals Case studies of the propagation characteristics of auroral TIDS with EISCAT CP2 data using maximum entropy cross-spectral analysis

1998 ◽  
Vol 16 (2) ◽  
pp. 161-167 ◽  
Author(s):  
S. Y. Ma ◽  
K. Schlegel ◽  
J. S. Xu
Keyword(s):  
Spectral Analysis ◽  
Phase Velocity ◽  
Maximum Entropy ◽  
Case Studies ◽  
Large Scale ◽  
Phase Speed ◽  
Wave Number ◽  
Propagation Characteristics ◽  
Dominant Period ◽  
Horizontal Wavelength

Abstract. In this paper case studies of propagation characteristics of two TIDs are presented which are induced by atmospheric gravity waves in the auroral F-region on a magnetic quiet day. By means of maximum entropy cross-spectral analysis of EISCAT CP2 data, apparent full wave-number vectors of the TIDs are obtained as a function of height. The analysis results show that the two events considered can be classified as moderately large-scale TID and medium-scale TID, respectively. One exhibits a dominant period of about 72 min, a mean horizontal phase speed of about 180 m/s (corresponding to a horizontal wavelength of about 780 km) directed south-eastwards and a vertical phase speed of 55 m/s for a height of about 300 km. The other example shows a dominant period of 44 min, a mean horizontal phase velocity of about 160 m/s (corresponding to a horizontal wavelength of about 420 km) directed southwestwards, and a vertical phase velocity of about 50 m/s at 250 km altitude.Key words. Ionosphere · Auroral ionosphere · Ionosphere-atmosphere interactions · Wave propagation)

A survey of fog and related optical propagation characteristics

1982 ◽  
Vol 20 (3) ◽  
pp. 481 ◽  
Author(s):  
Dorathy A. Stewart ◽  
Oskar M. Essenwanger
Keyword(s):  
Propagation Characteristics ◽  
Optical Propagation
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