The complex wave representation

1991 ◽  
pp. 66-71
Author(s):  
Torben T. Nielsen
Keyword(s):  
Complex Wave

Flow resistivity, characteristic impedance and complex wave number assessment of coconut fiber with thin thickness samples.

2017 ◽  
Author(s):  
Key Fonseca de Lima ◽  
Nilson Barbieri ◽  
Fernando Jun Hattori Terashima ◽  
Vinicius Antonio Grossl ◽  
Nelson Legat Filho
Keyword(s):  
Characteristic Impedance ◽  
Wave Number ◽  
Coconut Fiber ◽  
Complex Wave ◽  
Flow Resistivity ◽  
Complex Wave Number

Evidence of metamaterial physics at the geophysics scale: the METAFORET experiment

2019 ◽  
Author(s):  
Martin Lott ◽  
Philippe Roux ◽  
Stéphane Garambois ◽  
Philippe Guéguen ◽  
Andrea Colombi
Keyword(s):  
Surface Waves ◽  
Attenuation Length ◽  
Dense Forest ◽  
Complex Wave ◽  
Seismic Surface Waves ◽  
Source Excitation ◽  
Ground Penetrating ◽  
Dense Seismic Array ◽  
Seismic Wavefield ◽  
Large Frequency

Abstract The METAFORET experiment was designed to demonstrate that complex wave physics phenomena classically observed at the meso- and micro-scales in acoustics and in optics also apply at the geophysics scale. In particular, the experiment shows that a dense forest of trees can behave as a locally resonant metamaterial for seismic surface waves. The dense arrangement of trees anchored into the ground creates anomalous dispersion curves for surface waves, which highlight a large frequency band-gap around one resonant frequency of the trees, at ∼45 Hz. This demonstration is carried out through the deployment of a dense seismic array of ∼1000 autonomous geophones providing seismic recordings under vibrating source excitation at the transition between an open field and a forest. Additional geophysical equipment was deployed (e.g. ground-penetrating radar, velocimeters on trees) to provide essential complementary measurements. Insights and interpretations on the observed seismic wavefield, including the attenuation length, the intensity ratio between the field and the forest and the surface wave polarization, are validated with 2D numerical simulations of trees over a layered halfspace.

On the topology of the complex wave spectrum in a fluid‐coupled elastic layer

1989 ◽  
Vol 85 (3) ◽  
pp. 1074-1080 ◽  
Author(s):  
S. I. Rokhlin ◽  
D. E. Chimenti ◽  
A. H. Nayfeh
Keyword(s):  
Elastic Layer ◽  
Wave Spectrum ◽  
Complex Wave
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