scholarly journals OPPORTUNITIES FOR INTERACTIVE, PHYSICS-DRIVEN WAVE SIMULATION USING THE BOUSSINESQ-TYPE MODEL, CELERIS

2017 ◽  
pp. 11
Author(s):  
Sasan Tavakkol ◽  
Patrick Lynett
Keyword(s):  
Boundary Conditions ◽  
Wave Model ◽  
Simulation Software ◽  
Irregular Waves ◽  
Type Model ◽  
Model Parameters ◽  
Breaking Wave ◽  
Wave Simulation ◽  
Recent Developments ◽  
Language Environment

In this paper, we discuss the recent developments of our GPU-based Boussinesq-type wave simulation software, Celeris. This software is meant to serve the primary purpose of being interactive – i.e. allowing the user to modify the boundary conditions and model parameters as the model is running, and to see the effect of these changes immediately. To accomplish this, the model is coded in a shader language environment, and our physical variables (e.g. ocean surface elevation, water velocity) are represented in the model as graphical textures, which can therefore be rapidly rendered and visualized via a GPU. The model may run faster than real-time for problems with practical setups. Following a description of the numerical development of the wave model, we elaborate on the recent features that are added to the software such as irregular waves and uniform time series boundary conditions. Since the model is previously validated for breaking and non-breaking wave, in this paper, we compare the numerical results of the model with experimental results of a current benchmark and show its good agreement.

scholarly journals INTERACTIVE AND IMMERSIVE COASTAL HYDRODYNAMIC SIMULATION

2018 ◽  
pp. 63
Author(s):  
Patrick J. Lynett ◽  
Sasan Tavakkol
Keyword(s):  
Open Access ◽  
Boundary Conditions ◽  
Wave Model ◽  
Water Velocity ◽  
Model Parameters ◽  
Wave Interactions ◽  
Hydrodynamic Simulation ◽  
Wave Dynamics ◽  
Physical Variables ◽  
Language Environment

In this presentation, we will discuss the development and application of a GPU-based Boussinesq-type wave model. The novelty of this approach is that it is meant to serve the primary purpose of being interactive – allowing the user to modify the boundary conditions and model parameters as the model is running, and to see the effect of these changes immediately. To accomplish this, the model is coded in a shader language environment, and our physical variables (e.g. ocean surface elevation, water velocity) are represented in the model as textures, which can be rapidly rendered and visualized via a GPU. This software can help scientists better understand nearshore wave dynamics as it allows them to observe wave interactions in real-time and modify the boundary conditions and model parameters as the model is running to see the effect of these changes immediately. The model is named “Celeris”, and is released under the GNU (open-source, open-access) license.

scholarly journals An Overland Flood Model for Geographical Information Systems

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2397
Author(s):  
Ceyhun Ozcelik ◽  
Yuri Gorokhovich
Keyword(s):  
Surface Roughness ◽  
Information Systems ◽  
Boundary Conditions ◽  
Geographical Information Systems ◽  
Simulation Software ◽  
Geographical Information ◽  
Model Parameters ◽  
Gis Model ◽  
Flood Model ◽  
Spatio Temporal

A variety of flood models and commercial flood simulation software are provided in the literature, with different accuracies and precisions changing from coarse to fine, depending on model structure and detailed descriptions of basin and hydrologic properties. These models generally focus on river processes, taking overland processes as inputs of 1D or 2D hydrodynamic or hydrologic river flow models. Due to the discrete structure of overland flow and unknown-dynamic boundary conditions, such classical approaches are not cable of fast and reliable spatio–temporal estimations for overland flows, and require detailed and well-organized spatial data that cannot be immediately obtained during an emergency. A spatially-distributed Geographical Information Systems (GIS) based flood model is developed in this study to simulate overland floods, using cellular automata principles. GIS raster cells are considered hydrologic homogeneous areas throughout which hydrologic properties remain constant. Hydrodynamic flow principles, conservations of mass, momentum and energy are applied at pixel level to simulate floodwaters. The proposed GIS model is capable of directly manipulating spatio–temporal pixel level data (e.g., topography, precipitation, infiltration, surface roughness etc.) for modeling of rainfall-induced overland floods; therefore, it can provide fast, temporal and spatial flood depth estimations as well as maximum flood depths and times of concentration for all pixels throughout a study area. The model is quite simple and easy to apply via easily creatable GIS input layers, and is thus very convenient for preliminary engineering applications that need quick and fast response. Its main advantage is that it does not need a predefined flood boundary and boundary conditions. This advantage is especially valuable for coastal plains where delineation of a basin is generally too difficult. Floodwaters of Cyclone Nargis/Myanmar were simulated to test the model. Sensitivity analyses were applied to evaluate the effects of the model parameters (i.e., surface roughness and infiltration rates) on simulation results. The study shows that the proposed GIS model can be readily applied for the fast and inexpensive modeling of rainfall caused floods in areas where flood boundaries and boundary conditions cannot be clearly identified.

scholarly journals VALIDATION OF A DOUBLE-LAYER BOUSSINESQ-TYPE MODEL FOR HIGHLY NONLINEAR AND DISPERSIVE WAVES

2011 ◽  
Vol 1 (32) ◽  
pp. 14
Author(s):  
Florent Chazel ◽  
Michel Benoit ◽  
Alexandre Ern
Keyword(s):  
Laboratory Experiments ◽  
Irregular Waves ◽  
Type Model ◽  
Breaking Wave ◽  
Test Cases ◽  
Regular Waves ◽  
Dispersive Waves ◽  
One Dimensional ◽  
Highly Nonlinear ◽  
Nonlinearity Dispersion

A two-layer Boussinesq-type mathematical model has been recently introduced by the authors with the goal of modeling highly nonlinear and dispersive waves (Chazel et al. 2009). The analysis of this model has previously shown that it possesses excellent linear properties, up to kh = 10 at least, for dispersion, shoaling coefficient and vertical profile of orbital velocities. In the present work a numerical one-dimensional (1DH) version of model is developed based on a finite difference technique for meshing the spatial domain. It is then applied and verified against a set of three one-dimensional (1DH) test-cases for which either numerical or experimental reference results are available: i. nonlinear and dispersive regular waves of permanent form; ii. propagation of regular waves on a trapezoidal bar (laboratory experiments by Dingemans (1994)); iii. shoaling and propagation of irregular waves on a barred beach profile (laboratory experiments by Becq-Girard et al. (1999)). The test-cases considered in this study confirm the very good capabilities of the model to reproduce either exact solutions, high-precision numerical simulations and experimental measurements in a variety of non-breaking wave conditions and types of bottom profiles. Nonlinearity, dispersion and bathymetric effects are well accounted for by the model, which appears to possess a rather wide domain of validity while maintaining a reasonable level of complexity.

Model of vortex flow of charge in a vessel with turbine impeller

1987 ◽  
Vol 52 (8) ◽  
pp. 1888-1904
Author(s):  
Miloslav Hošťálek ◽  
Ivan Fořt
Keyword(s):  
Boundary Conditions ◽  
Equations Of Motion ◽  
Theoretical Data ◽  
Eddy Diffusion ◽  
Quantitative Agreement ◽  
Creeping Flow ◽  
Model Parameters ◽  
Mean Flow ◽  
Two Dimensional Flow ◽  
Vorticity Transport

A theoretical model is described of the mean two-dimensional flow of homogeneous charge in a flat-bottomed cylindrical tank with radial baffles and six-blade turbine disc impeller. The model starts from the concept of vorticity transport in the bulk of vortex liquid flow through the mechanism of eddy diffusion characterized by a constant value of turbulent (eddy) viscosity. The result of solution of the equation which is analogous to the Stokes simplification of equations of motion for creeping flow is the description of field of the stream function and of the axial and radial velocity components of mean flow in the whole charge. The results of modelling are compared with the experimental and theoretical data published by different authors, a good qualitative and quantitative agreement being stated. Advantage of the model proposed is a very simple schematization of the system volume necessary to introduce the boundary conditions (only the parts above the impeller plane of symmetry and below it are distinguished), the explicit character of the model with respect to the model parameters (model lucidity, low demands on the capacity of computer), and, in the end, the possibility to modify the given model by changing boundary conditions even for another agitating set-up with radially-axial character of flow.

Simulation and Simulation Software Development of the Braking Process of a Subway Train

2014 ◽  
Vol 556-562 ◽  
pp. 294-301 ◽  
Author(s):  
Long Han ◽  
Chun Tian ◽  
Yan Wang ◽  
Meng Ling Wu ◽  
Zhuo Jun Luo
Keyword(s):  
Computational Effort ◽  
Simulation Software ◽  
System Model ◽  
Brake System ◽  
Railway Vehicle ◽  
Model Parameters ◽  
Modeling Process ◽  
Time Simulation ◽  
Subway Train ◽  
Braking Process

This paper deals with the problem of braking process modeling. A subway train braking process simulation software is built, which composes of a GUI and a underlying model. The underlying model consists of a train model and a brake system model. The train model is simplified and built by assembling subcomponent element models of a railway vehicle. The brake system model is simplified and built based on experimental data in order to reduce computational effort. The GUI of the software can be use to input model parameters, display simulation results, and store simulation data. As a result of the simplifications of the modeling process, the developed software can perform real time simulation.

scholarly journals Noninteractive Macroscopic Reliability Model for Ceramic Matrix Composites With Orthotropic Material Symmetry

1990 ◽  
Vol 112 (4) ◽  
pp. 507-511 ◽  
Author(s):  
S. F. Duffy ◽  
J. M. Manderscheid
Keyword(s):  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Experimental Program ◽  
Type Model ◽  
Model Parameters ◽  
Reliability Model ◽  
Matrix Composites ◽  
Physical Mechanisms ◽  
Weakest Link ◽  
Monolithic Ceramics

A macroscopic noninteractive reliability model for ceramic matrix composites is presented. The model is multiaxial and applicable to composites that can be characterized as orthotropic. Tensorial invariant theory is used to create an integrity basis with invariants that correspond to physical mechanisms related to fracture. This integrity basis is then used to construct a failure function per unit volume (or area) of material. It is assumed that the overall strength of the composite is governed by weakest link theory. This leads to a Weibull-type model similar in nature to the principle of independent action (PIA) model for isotropic monolithic ceramics. An experimental program to obtain model parameters is briefly discussed. In addition, qualitative features of the model are illustrated by presenting reliability surfaces for various model parameters.

The Summary of the Durability of Concrete Parameters Calculation Models

2011 ◽  
Vol 71-78 ◽  
pp. 937-944
Author(s):  
Ping Jie Cheng ◽  
Han Zhou Hu ◽  
Shu Guang Hu
Keyword(s):  
Environmental Effects ◽  
Concrete Structure ◽  
Civil Engineering ◽  
Steel Corrosion ◽  
Type Model ◽  
Model Parameters ◽  
Source Type ◽  
Important Field ◽  
Parameters Calculation ◽  
Durability Of Concrete

The durability of concrete structure has become an important field of civil engineering at home and abroad, and how to determine the environmental effects of typical durability of concrete structure key parameters become the key. Proposed by different domestic and foreign scholars to study durability parameters of concrete structure of different models, different models are different in the source, type, model parameters and applicable conditions. In this paper, some typical models are reviewed and analyzed from two major aspects of the durability of concrete, the deterioration of concrete and the steel corrosion.

Updating Substructure Models With Dynamic Boundary Conditions

1995 ◽  
Author(s):  
Michael Link ◽  
Zheng Qian
Keyword(s):  
Boundary Conditions ◽  
Dynamic Stiffness ◽  
Design Parameters ◽  
Physical Parameters ◽  
Model Parameters ◽  
Dynamic Boundary Conditions ◽  
Main Structure ◽  
Modal Data ◽  
Residual Structure ◽  
Dynamic Boundary

Abstract In recent years procedures for updating analytical model parameters have been developed by minimizing differences between analytical and preferably experimental modal analysis results. Provided that the initial analysis model contains parameters capable of describing possible damage these techniques could also be used for damage detection. In this case the parameters are updated using test data before and after the damage. Looking at complex structures with hundreds of parameters one generally has to measure the modal data at many locations and try to reduce the number of unknown parameters by some kind of localization technique because the measurement information is generally not sufficient to identify all the parameters equally distributed all over the structure. Another way of reducing the number of parameters shall be presented here. This method is based on the idea of measuring only a part of the structure and replacing the residual structure by dynamic boundary conditions which describe the dynamic stiffness at the interfaces between the measured main structure and the remaining unmeasured residual structure. This approach has some advantage since testing could be concentrated on critical areas where structural modifications are expected either due to damage or due to intended design changes. The dynamic boundary conditions are expressed in Craig-Bampton (CB) format by transforming the mass and stiffness matrices of the unmeasured residual structure to the interface degrees of freedom (DOF) and to the modal DOFs of the residual structure fixed at the interface. The dynamic boundary stiffness concentrates all physical parameters of the residual structure in only a few parameters which are open for updating. In this approach damage or modelling errors within the unmeasured residual structure are taken into account only in a global sense whereas the measured main structure is parametrized locally as usual by factoring mass and stiffness submatrices defining the type and the location of the physical parameters to be identified. The procedure was applied to identify the design parameters of a beam type frame structure with bolted joints using experimental modal data.

scholarly journals COMPARATIVE ANALYSIS OF DIFFERENT CAD METHODS FOR EXTRACTION OF THE HEMT NOISE WAVE MODEL PARAMETERS

2017 ◽  
Vol 16 (2) ◽  
pp. 117
Author(s):  
Vladica Đorđević ◽  
Zlatica Marinković ◽  
Olivera Pronić-Rančić
Keyword(s):  
Comparative Analysis ◽  
Electron Mobility ◽  
Computer Aided Design ◽  
Wave Model ◽  
High Electron Mobility Transistor ◽  
Extraction Methods ◽  
Model Parameters ◽  
High Electron ◽  
High Electron Mobility ◽  
Noise Modeling

The noise wave model has appeared as a very appropriate model for the purpose of transistor noise modeling at microwave frequencies. The transistor noise wave model parameters are usually extracted from the measured transistor noise parameters by using time-consuming optimization procedures in microwave circuit simulators. Therefore, three different Computer-Aided Design methods that enable more efficient automatic determination of these parameters in the case of high electron-mobility transistors were developed. All of these extraction methods are based on different noise de-embedding procedures, which are described in detail within this paper. In order to validate the presented extraction methods, they were applied for the noise modeling of a specific GaAs high electron-mobility transistor. Finally, the obtained results were used for the comparative analysis of the presented extraction approaches in terms of accuracy, complexity and effectiveness.

scholarly journals NON-BREAKING AND BREAKING WAVE LOADS ON A COOLING WATER OUTFALL

1978 ◽  
Vol 1 (16) ◽  
pp. 148
Author(s):  
G.R. Mogridge ◽  
W.W. Jamieson
Keyword(s):  
Water Level ◽  
Cooling Water ◽  
High Water ◽  
Breaking Waves ◽  
Irregular Waves ◽  
Scale Model ◽  
Breaking Wave ◽  
Wave Loads ◽  
Eastern Canada ◽  
Spilling Breakers

Cooling water from a power generating station in Eastern Canada is pumped to an outfall and distributed into the ocean through discharge ports in the sidewalls of a diffuser cap. The cap is essentially a shell-type structure consisting of a submerged circular cylinder 26.5 ft in diameter and 14 ft high. It is located in 25 ft of water at low water level and 54 ft at high water level. Horizontal forces, vertical forces and overturning moments exerted by waves on a 1:36 scale model of the diffuser cap were measured with and without cooling water discharging from the outfall. Tests were run with regular and irregular waves producing both non-breaking and breaking wave loads on the diffuser cap. The overturning moments measured on the diffuser cap were up to 150 percent greater than those on a solid submerged cylinder sealed to the seabed. Unlike sealed cylinders, all of the wave loads measured on the relatively open structure reached maximum values at approximately the same time. The largest wave loads were measured on the diffuser structure when it was subjected to spilling breakers at low water level. For a given wave height, the spilling breakers caused wave loads up to 100 percent greater than those due to non-breaking waves.

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