scholarly journals EFFECT OF BOUSSINESQ EQUATIONS ON WAVE SPECTRA PROPAGATION

1988 ◽  
Vol 1 (21) ◽  
pp. 24
Author(s):  
J.P. Sierra ◽  
A.S. Arcilla ◽  
J.J. Egozcue ◽  
J.L. Monso
Keyword(s):  
Time Series ◽  
Wave Propagation ◽  
Spectral Analysis ◽  
Numerical Model ◽  
Boussinesq Equations ◽  
Density Functions ◽  
Wave Spectra ◽  
Irregular Wave ◽  
Propagation Effects ◽  
Spectral Density Functions

A 2-D numerical model has been developed to simulate wave propagation prior to breaking. This non linear hydrodynamic model works in connection with various spectral analysis routines. This paper intends to study the propagation effects on the wave time-series and on the corresponding spectral density functions in order to gain insight on both the spectral description of waves and irregular wave propagation.

scholarly journals COUPLING OF A BOUSSINESQ WAVE MODEL WITH A MOORED SHIP BEHAVIOR MODEL

2012 ◽  
Vol 1 (33) ◽  
pp. 69 ◽  
Author(s):  
Liliana Vieira Pinheiro ◽  
Conceição Fortes ◽  
João Santos ◽  
José Leonel Fernandes
Keyword(s):  
Time Series ◽  
Wave Propagation ◽  
Numerical Model ◽  
Wave Model ◽  
Wave Forces ◽  
Behavior Model ◽  
Nonlinear Wave Propagation ◽  
Practical Applications ◽  
Ship Behavior

A set of procedures to evaluate the time series of the diffraction forces on a moored ship inside a harbor basin is presented. Nonlinear wave propagation is obtained using a Boussinesq finite element numerical model, BOUSS-WMH. Determination of hydrodynamic forces acting on the ship is achieved using a modified version of the WAMIT model. Finally, time series of the wave forces on the ship and of the inherent motions of the moored ship are obtained using BAS numerical model. The main focuses of this work are: the coupling of these three models and the modification of the method used in WAMIT to determine diffraction forces. Some simple and practical applications of this procedure are presented as well.

Periods of planetary waves in geomagnetic variations

1995 ◽  
Vol 13 (2) ◽  
pp. 168-176 ◽  
Author(s):  
A. Kohsiek ◽  
K. H. Glassmeier ◽  
T. Hirooka
Keyword(s):  
Time Series ◽  
Wave Propagation ◽  
Spectral Analysis ◽  
Temporal Variations ◽  
Planetary Waves ◽  
Clear Correlation ◽  
Time Interval ◽  
Geomagnetic Variations ◽  
Dynamic Spectra ◽  
Height Data

Abstract. Periods of planetary waves, especially the 10- and 16-day waves, were found in Fourier analyses of 10-year geomagnetic time series from two mid-latitude stations in the northern hemisphere. This suggests that planetary waves influence geomagnetic variations. Cross-spectral analysis of magnetic time series from seven stations located at around 50°N at the beginning of 1979, when a 16-day wave occurred in the stratosphere, also shows a 16-day oscillation. However, study of the phases does not reveal the horizontal direction of wave propagation. Furthermore, the temporal variations of the 16-day oscillation in magnetic time series are presented as dynamic spectra and the results are compared with global investigations of geopotential height data at 1 hPa (around 48 km) with respect to the 16-day wave for the same time interval. In some cases this comparison suggests a clear correlation between geomagnetic variations and planetary waves as well as a propagation of the 16-day wave up to the dynamo region (100-170 km).

Wave propagation improvement in two-dimensional bond-based peridynamics model

2021 ◽  
pp. 095440622098555
Author(s):  
Reza Alebrahim ◽  
Pawel Packo ◽  
Mirco Zaccariotto ◽  
Ugo Galvanetto
Keyword(s):  
Wave Propagation ◽  
Dynamic Performance ◽  
Numerical Dispersion ◽  
Motion Modeling ◽  
Minimization Method ◽  
Irregular Wave ◽  
Point Collocation ◽  
Potential Applications ◽  
Non Local ◽  
Set Up

In this study, methods to mitigate anomalous wave propagation in 2-D Bond-Based Peridynamics (PD) are presented. Similarly to what happens in classical non-local models, an irregular wave transmission phenomenon occurs at high frequencies. This feature of the dynamic performance of PD, limits its potential applications. A minimization method based on the weighted residual point collocation is introduced to substantially extend the frequency range of wave motion modeling. The optimization problem, developed through inverse analysis, is set up by comparing exact and numerical dispersion curves and minimizing the error in the frequency-wavenumber domain. A significant improvement in the wave propagation simulation using Bond-Based PD is observed.

scholarly journals Assessing Stream-Aquifer Connectivity in a Coastal California Watershed

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 416
Author(s):  
Bwalya Malama ◽  
Devin Pritchard-Peterson ◽  
John J. Jasbinsek ◽  
Christopher Surfleet
Keyword(s):  
Time Series ◽  
Spectral Analysis ◽  
Water Level ◽  
Time Series Data ◽  
Series Data ◽  
Low Permeability ◽  
Pumping Tests ◽  
Stream Flows ◽  
The Impact

We report the results of field and laboratory investigations of stream-aquifer interactions in a watershed along the California coast to assess the impact of groundwater pumping for irrigation on stream flows. The methods used include subsurface sediment sampling using direct-push drilling, laboratory permeability and particle size analyses of sediment, piezometer installation and instrumentation, stream discharge and stage monitoring, pumping tests for aquifer characterization, resistivity surveys, and long-term passive monitoring of stream stage and groundwater levels. Spectral analysis of long-term water level data was used to assess correlation between stream and groundwater level time series data. The investigations revealed the presence of a thin low permeability silt-clay aquitard unit between the main aquifer and the stream. This suggested a three layer conceptual model of the subsurface comprising unconfined and confined aquifers separated by an aquitard layer. This was broadly confirmed by resistivity surveys and pumping tests, the latter of which indicated the occurrence of leakage across the aquitard. The aquitard was determined to be 2–3 orders of magnitude less permeable than the aquifer, which is indicative of weak stream-aquifer connectivity and was confirmed by spectral analysis of stream-aquifer water level time series. The results illustrate the importance of site-specific investigations and suggest that even in systems where the stream is not in direct hydraulic contact with the producing aquifer, long-term stream depletion can occur due to leakage across low permeability units. This has implications for management of stream flows, groundwater abstraction, and water resources management during prolonged periods of drought.

Sign in / Sign up

Export Citation Format

Share Document