Prediction of Water Wave Propagation Using Computational Fluid Dynamics

2013 ◽  
Author(s):  
Mohammadreza Javanmardi ◽  
Jonathan Binns ◽  
Giles Thomas ◽  
Martin R. Renilson
Keyword(s):  
Experimental Data ◽  
Wave Propagation ◽  
Free Surface ◽  
Water Wave ◽  
Three Dimensional ◽  
Source Model ◽  
Quality Parameters ◽  
Mesh Quality ◽  
Pressure Source ◽  
Moving Body

In this study the influence of grid effects on free surface deformations behind a ship-like moving vessel were investigated. To determine the influence of grid effects on the water wave propagation, various grid domains with different quality parameters were produced. Simulations were conducted for a moving pressure source and the free surface around the moving body captured. Then three-dimensional numerical results for different grids, in both the near and far field, were compared with experimental data over a range of speeds. The experimental data were obtained using tank tests on a pressure source model at the Australian Maritime College. Wave probes at different lateral distances captured the generated wave parameters. The study revealed that the results of numerical simulation of water wave propagation depend on the grid parameters and geometrical mesh quality.

scholarly journals Bechmann’s Number for Harmonic Overtones of Thickness-Shear Vibrations of Rotated Y-Cut Quartz Crystal Plates

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 667
Author(s):  
Han Zhang ◽  
Yumei Chen ◽  
Ji Wang
Keyword(s):  
Experimental Data ◽  
Wave Propagation ◽  
Quartz Crystal ◽  
Three Dimensional ◽  
Approximate Solutions ◽  
Superior Performance ◽  
Shear Modes ◽  
Practical Experiences ◽  
Quartz Crystal Resonators ◽  
Thickness Shear

A procedure based on approximate solutions of three-dimensional equations of wave propagation is utilized for calculating Bechmann’s number for the harmonic overtones of thickness-shear modes in the rotated Y-cut quartz crystal plates. Bechmann’s number is used for the optimization and improvement of electrodes to yield superior performance in the design of quartz crystal resonators. Originally, Bechmann’s number is found through practical experiences, and analytical results were provided afterward to enable optimal design of novel resonator structures. The outcomes in this study are from a simplified theoretical prediction and they are consistent with known empirical results, making it is possible to design optimal quartz crystal resonators for cases without adequate experimental data for a higher frequency and smaller size.

Acoustic-Emission Wave Response to a Dislocation Source in Layered Media

2014 ◽  
Vol 598 ◽  
pp. 135-140
Author(s):  
Rui Chong Zhang
Keyword(s):  
Acoustic Emission ◽  
Wave Propagation ◽  
Free Surface ◽  
Integral Transformation ◽  
Three Dimensional ◽  
Closed Form Solution ◽  
Form Solution ◽  
Arbitrary Orientation ◽  
Dislocation Source ◽  
Time Space

This paper presents synthesis of acoustic-emission (AE) wave propagation in multi-layer materials and simulation of AE wave responses at free surface. In particular, the AE source is modelled as an arbitrary-orientation dislocation over an inclined-to-surface fault within one layer or at the layer-to-layer interface, while the materials are assumed as multi-layer media, each of which is homogeneous, isotropic and linearly elastic. With the use of the integral transformation approach, the three-dimensional wave propagation in the materials is solved in transformed or frequency-wavenumber domain. Subsequently, a closed-form solution for wave responses at free surface is found, which can then be converted in time-space domain. Numerical examples are finally provided for illustration.

Three-dimensional flow evolution after a dam break

2010 ◽  
Vol 663 ◽  
pp. 456-477 ◽  
Author(s):  
A. FERRARI ◽  
L. FRACCAROLLO ◽  
M. DUMBSER ◽  
E. F. TORO ◽  
A. ARMANINI
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Shallow Water ◽  
Three Dimensional ◽  
Dam Break ◽  
Water Model ◽  
Navier Stokes ◽  
Finite Volume Scheme ◽  
Shallow Water Model ◽  
Weakly Compressible

In this paper, the wave propagation on a plane dry bottom after a dam break is analysed. Two mathematical models have been used and compared with each other for simulating such a dam-break scenario. First, the fully three-dimensional Navier–Stokes equations for a weakly compressible fluid have been solved using the new smooth particle hydrodynamics formulation, recently proposed by Ferrari et al. (Comput. Fluids, vol. 38, 2009, p. 1203). Second, the two-dimensional shallow water equations (SWEs) are solved using a third-order weighted essentially non-oscillatory finite-volume scheme. The numerical results are critically compared against the laboratory measurements provided by Fraccarollo & Toro (J. Hydraul. Res., vol. 33, 1995, p. 843). The experimental data provide the temporal evolution of the pressure field, the water depth and the vertical velocity profile at 40 gauges, located in the reservoir and in front of the gate. Our analysis reveals the shortcomings of SWEs in the initial stages of the dam-break phenomenon in reproducing many important flow features of the unsteady free-surface flow: the shallow water model predicts a complex wave structure and a wavy evolution of local free-surface elevations in the reservoir that can be clearly identified to be only model artefacts. However, the quasi-incompressible Navier–Stokes model reproduces well the high gradients in the flow field and predicts the cycles of simultaneous rapid decreasing and frozen stages of the free surface in the tank along with the velocity oscillations. Asymptotically, i.e. for ‘large times’, the shallow water model and the weakly compressible Navier–Stokes model agree well with the experimental data, since the classical SWE assumptions are satisfied only at large times.

scholarly journals Image-based processing simulation of shock wave propagation through the area of ionization instability

2021 ◽  
Vol 2127 (1) ◽  
pp. 012013
Author(s):  
V Kravchenko ◽  
O A Azarova ◽  
T A Lapushkina
Keyword(s):  
Experimental Data ◽  
Shock Wave ◽  
Image Processing ◽  
Wave Propagation ◽  
Digital Processing ◽  
Source Model ◽  
Navier Stokes ◽  
Automatic Method ◽  
The Real ◽  
Real Geometry

Abstract A partially automatic method of digital processing images (photographs, shadow and Schlieren pictures) for the analysis of experimental data is proposed. The method is utilized to investigate the effect of the region of ionization instability created by a glow gas discharge on the front of an initially flat shock wave. The proposed method is based on a composition of simple image processing operations and makes it possible to perform simulations taking into account the real geometry of the ionization strata and the shape of the front of a shock wave based on the obtained experimental images. First, as a result of digital processing the geometry of experimental objects is extracted from the images. This information is then embedded in the Navier-Stokes code for conducting simulations. New results for the real geometry of ionization strata of different scales are presented which confirmed the previous ones obtained for the density homogeneously stratified source model.

Synthesis of Acoustic-Emission Wave Propagation in Multi-Layer Media

2013 ◽  
Vol 321-324 ◽  
pp. 1321-1330
Author(s):  
Rui Chong Zhang ◽  
Alhamid Alamin
Keyword(s):  
Acoustic Emission ◽  
Wave Propagation ◽  
Free Surface ◽  
Integral Transformation ◽  
Three Dimensional ◽  
Closed Form Solution ◽  
Form Solution ◽  
Arbitrary Orientation ◽  
Numerical Examples ◽  
Time Space

This paper presents synthesis of acoustic-emission (AE) wave propagation in multi-layer materials and simulation of AE wave responses at free surface. In particular, the AE source is modelled as an arbitrary-orientation dislocation over an inclined-to-surface fault within one layer or at the layer-to-layer interface, while the materials are assumed as multi-layer media, each of which is homogeneous, isotropic and linearly elastic. With the use of the integral transformation approach, the three-dimensional wave propagation in the materials is solved in transformed or frequency-wavenumber domain. Subsequently, a closed-form solution for wave responses at free surface is found, which can then be converted in time-space domain. Numerical examples are finally provided for illustration.

Three-Dimensional Cartesian Grid Method for the Simulations of Flows with Shock Waves in the Domains with Varying Boundaries

2020 ◽  
pp. 2050046
Author(s):  
V. V. Elesin ◽  
D. A. Sidorenko ◽  
P. S. Utkin
Keyword(s):  
Experimental Data ◽  
Shock Wave ◽  
Wave Propagation ◽  
Three Dimensional ◽  
Grid Method ◽  
Cartesian Grid ◽  
Computational Cell ◽  
Cartesian Grid Method ◽  
Moving Particle

This paper is devoted to the development and quantitative evaluation of the properties of the numerical algorithm of the Cartesian grid method for three-dimensional (3D) simulation of shock-wave propagation in areas of varying shape. The detailed description of the algorithm is presented. The algorithm is relatively simple to implement and does not require solving the problem of determination of the shape of the body’s boundary intersection with regular computational cell. The accuracy of the algorithm is demonstrated by comparing the simulated and experimental data in the problems of the interaction of a shock wave (SW) with a nonmoving sphere and a moving particle.

scholarly journals BUBBLE BURSTING AT A FREE SURFACE IN A CLOSED DOMAIN

2016 ◽  
Vol 42 ◽  
pp. 1660160
Author(s):  
NIAN-NIAN LIU ◽  
SHUAI ZHANG ◽  
SHI-PING WANG
Keyword(s):  
Wave Propagation ◽  
Free Surface ◽  
Laplace Equation ◽  
Water Waves ◽  
Water Wave ◽  
Velocity Potential ◽  
Boundary Integral ◽  
Boundary Integral Method ◽  
Closed Domain ◽  
Bubble Motion

When a charge explodes underwater near a free surface, a bubble would be generated and the surface pushed up very high. Experiments have shown that the motion of the spike lags a lot behind the bubble motion. Many studies only focus on the nonlinear interaction between the bubble and free surface while the water waves afterward is mainly studied based on the linear theory. The nonlinear motion of the water wave after the bubble pulsation is seldom studied. In this study, we concerns the interaction between underwater explosion generated bubble and a free surface and its bursting at a free surface in a closed domain. Suppose that the fluid outside the bubble is incompressible, non-viscous and irrotational and the velocity potential satisfies the Laplace equation. Boundary integral method is used to solve the Laplace equation for the velocity potential. The bubble content is described by an adiabatic law. The whole process of the bubble motion and subsequently the water wave propagation will be simulated in this paper. Particular attention will be focused on the phenomenon of water wave propagation in a closed domain.

Analysis of athletes’ stadium stress source based on improved layered K-means algorithm

2020 ◽  
Vol 39 (4) ◽  
pp. 5905-5914
Author(s):  
Chen Gong
Keyword(s):  
Experimental Data ◽  
Machine Learning Algorithms ◽  
User Preference ◽  
Experimental Comparison ◽  
Actual Situation ◽  
Medical Field ◽  
Pressure Source ◽  
Preference Model ◽  
Related Research ◽  
Analysis System

Most of the research on stressors is in the medical field, and there are few analysis of athletes’ stressors, so it can not provide reference for the analysis of athletes’ stressors. Based on this, this study combines machine learning algorithms to analyze the pressure source of athletes’ stadium. In terms of data collection, it is mainly obtained through questionnaire survey and interview form, and it is used as experimental data after passing the test. In order to improve the performance of the algorithm, this paper combines the known K-Means algorithm with the layering algorithm to form a new improved layered K-Means algorithm. At the same time, this paper analyzes the performance of the improved hierarchical K-Means algorithm through experimental comparison and compares the clustering results. In addition, the analysis system corresponding to the algorithm is constructed based on the actual situation, the algorithm is applied to practice, and the user preference model is constructed. Finally, this article helps athletes find stressors and find ways to reduce stressors through personalized recommendations. The research shows that the algorithm of this study is reliable and has certain practical effects and can provide theoretical reference for subsequent related research.

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