Three-dimensional hybrid asynchronous perfectly matched layer for wave propagation in heterogeneous semi-infinite media

Dam-break flood waves represent a severe threat to people and properties located in downstream regions. Although dam failure has been among the main subjects investigated in academia, little effort has been made toward investigating wave propagation under the influence of tailwater depth. This work presents three-dimensional (3D) numerical simulations of laboratory experiments of dam-breaks with tailwater performed at the Laboratory of Hydraulics of Iskenderun Technical University, Turkey. The dam-break wave was generated by the instantaneous removal of a sluice gate positioned at the center of a transversal wall forming the reservoir. Specifically, in order to understand the influence of tailwater level on wave propagation, three tests were conducted under the conditions of dry and wet downstream bottom with two different tailwater depths, respectively. The present research analyzes the propagation of the positive and negative wave originated by the dam-break, as well as the wave reflection against the channel’s downstream closed boundary. Digital image processing was used to track water surface patterns, and ultrasonic sensors were positioned at five different locations along the channel in order to obtain water stage hydrographs. Laboratory measurements were compared against the numerical results obtained through FLOW-3D commercial software, solving the 3D Reynolds-Averaged Navier–Stokes (RANS) with the k-ε turbulence model for closure, and Shallow Water Equations (SWEs). The comparison achieved a reasonable agreement with both numerical models, although the RANS showed in general, as expected, a better performance.

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Guided Surface Waves on an Elastic Half Space

Journal of Applied Mechanics ◽

10.1115/1.3408973 ◽

1971 ◽

Vol 38 (4) ◽

pp. 899-905 ◽

Cited By ~ 5

Author(s):

L. B. Freund

Keyword(s):

Wave Propagation ◽

Surface Wave ◽

Surface Waves ◽

Half Space ◽

Body Wave ◽

Three Dimensional ◽

Elastic Half Space ◽

Normal Displacement ◽

Rigid Barrier ◽

Wave Disturbances

Three-dimensional wave propagation in an elastic half space is considered. The half space is traction free on half its boundary, while the remaining part of the boundary is free of shear traction and is constrained against normal displacement by a smooth, rigid barrier. A time-harmonic surface wave, traveling on the traction free part of the surface, is obliquely incident on the edge of the barrier. The amplitude and the phase of the resulting reflected surface wave are determined by means of Laplace transform methods and the Wiener-Hopf technique. Wave propagation in an elastic half space in contact with two rigid, smooth barriers is then considered. The barriers are arranged so that a strip on the surface of uniform width is traction free, which forms a wave guide for surface waves. Results of the surface wave reflection problem are then used to geometrically construct dispersion relations for the propagation of unattenuated guided surface waves in the guiding structure. The rate of decay of body wave disturbances, localized near the edges of the guide, is discussed.

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Long waves in a straight channel with non-uniform cross-section

Journal of Fluid Mechanics ◽

10.1017/jfm.2015.147 ◽

2015 ◽

Vol 770 ◽

pp. 156-188 ◽

Cited By ~ 5

Author(s):

Patricio Winckler ◽

Philip L.-F. Liu

Keyword(s):

Boundary Layer ◽

Wave Propagation ◽

Cross Section ◽

Three Dimensional ◽

Channel Cross Section ◽

Cross Sectional ◽

New Model ◽

One Dimensional ◽

Uniform Channel ◽

The Cross

A cross-sectionally averaged one-dimensional long-wave model is developed. Three-dimensional equations of motion for inviscid and incompressible fluid are first integrated over a channel cross-section. To express the resulting one-dimensional equations in terms of the cross-sectional-averaged longitudinal velocity and spanwise-averaged free-surface elevation, the characteristic depth and width of the channel cross-section are assumed to be smaller than the typical wavelength, resulting in Boussinesq-type equations. Viscous effects are also considered. The new model is, therefore, adequate for describing weakly nonlinear and weakly dispersive wave propagation along a non-uniform channel with arbitrary cross-section. More specifically, the new model has the following new properties: (i) the arbitrary channel cross-section can be asymmetric with respect to the direction of wave propagation, (ii) the channel cross-section can change appreciably within a wavelength, (iii) the effects of viscosity inside the bottom boundary layer can be considered, and (iv) the three-dimensional flow features can be recovered from the perturbation solutions. Analytical and numerical examples for uniform channels, channels where the cross-sectional geometry changes slowly and channels where the depth and width variation is appreciable within the wavelength scale are discussed to illustrate the validity and capability of the present model. With the consideration of viscous boundary layer effects, the present theory agrees reasonably well with experimental results presented by Chang et al. (J. Fluid Mech., vol. 95, 1979, pp. 401–414) for converging/diverging channels and those of Liu et al. (Coast. Engng, vol. 53, 2006, pp. 181–190) for a uniform channel with a sloping beach. The numerical results for a solitary wave propagating in a channel where the width variation is appreciable within a wavelength are discussed.

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Application of the perfectly matched layer in numerical modeling of wave propagation with an irregular free surface

10.1190/segam2013-0277.1 ◽

2013 ◽

Author(s):

Youshan Liu ◽

Jianguo Zhao

Keyword(s):

Numerical Modeling ◽

Wave Propagation ◽

Free Surface ◽

Perfectly Matched Layer ◽

Irregular Free Surface

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Wave Propagation Analysis in Composite Laminates Containing a Delamination Using a Three-Dimensional Spectral Element Method

Mathematical Problems in Engineering ◽

10.1155/2012/659849 ◽

2012 ◽

Vol 2012 ◽

pp. 1-19 ◽

Cited By ~ 7

Author(s):

Fucai Li ◽

Haikuo Peng ◽

Xuewei Sun ◽

Jinfu Wang ◽

Guang Meng

Keyword(s):

Wave Propagation ◽

Lamb Wave ◽

Composite Laminates ◽

Composite Structures ◽

Spectral Element Method ◽

Three Dimensional ◽

Spectral Element ◽

Wave Mode ◽

Diagonal Form ◽

Element Method

A three-dimensional spectral element method (SEM) was developed for analysis of Lamb wave propagation in composite laminates containing a delamination. SEM is more efficient in simulating wave propagation in structures than conventional finite element method (FEM) because of its unique diagonal form of the mass matrix. Three types of composite laminates, namely, unidirectional-ply laminates, cross-ply laminates, and angle-ply laminates are modeled using three-dimensional spectral finite elements. Wave propagation characteristics in intact composite laminates are investigated, and the effectiveness of the method is validated by comparison of the simulation results with analytical solutions based on transfer matrix method. Different Lamb wave mode interactions with delamination are evaluated, and it is demonstrated that symmetric Lamb wave mode may be insensitive to delamination at certain interfaces of laminates while the antisymmetric mode is more suited for identification of delamination in composite structures.

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