scholarly journals Tsunami propagation kernel and its applications

2021 ◽  
Vol 21 (7) ◽  
pp. 2093-2108
Author(s):  
Takenori Shimozono
Keyword(s):  
Shallow Water ◽  
Kernel Method ◽  
Numerical Models ◽  
Computational Cost ◽  
Specific Area ◽  
Tsunami Propagation ◽  
Wave Data ◽  
Kernel Convolution ◽  
Tsunami Risk ◽  
Offshore Wave

Abstract. Tsunamis rarely occur in a specific area, and their occurrence is highly uncertain. Suddenly generated from their sources in deep water, they occasionally undergo tremendous amplification in shallow water to devastate low-lying coastal areas. Despite the advancement of computational power and simulation algorithms, there is a need for novel and rigorous approaches to efficiently predict coastal amplification of tsunamis during different disaster management phases, such as tsunami risk assessment and real-time forecast. This study presents convolution kernels that can instantly predict onshore waveforms of water surface elevation and flow velocity from observed/simulated wave data away from the shore. Kernel convolution involves isolating an incident-wave component from the offshore wave data and transforming it into the onshore waveform. Moreover, unlike previously derived ones, the present kernels are based on shallow-water equations with a damping term and can account for tsunami attenuation on its path to the shore with a damping parameter. Kernel convolution can be implemented at a low computational cost compared to conventional numerical models that discretise the spatial domain. The prediction capability of the kernel method was demonstrated through application to real-world tsunami cases.

scholarly journals Tsunami propagation kernel and its applications

2021 ◽  
Author(s):  
Takenori Shimozono
Keyword(s):  
Kernel Method ◽  
Numerical Models ◽  
Computational Cost ◽  
Specific Area ◽  
Tsunami Propagation ◽  
Kernel Convolution ◽  
Damping Parameter ◽  
Tsunami Risk ◽  
Convolution Kernels ◽  
Low Computational Cost

Abstract. Tsunamis rarely occur in a specific area, and their occurrence is highly uncertain. Generated from their sources in deep water, they occasionally undergo tremendous amplification over decreasing water depth to devastate low-lying coastal areas. Despite the advancement of computational power and simulation algorithms, there is a need for novel and rigorous approaches to efficiently predict coastal amplification of tsunamis during different disaster management phases, such as tsunami risk assessment and real-time forecast. This study presents convolution kernels that can instantly predict onshore waveforms of water surface elevation and flow velocity from observed/simulated wavedata apart from the shore. Kernel convolution involves isolating an incident-wave component from the offshore wavedata and transforming it into the onshore waveform. Moreover, unlike previous derived ones, the present kernels are based on shallow-water equations with a damping term and can account for tsunami attenuation on its path to the shore with a damping parameter. Kernel convolution can be implemented at a low computational cost compared to conventional numerical models that discretise the spatial domain. The prediction capability of the kernel method was demonstrated through application to real-world tsunami cases.

scholarly journals Wave Climate at Shallow Waters along the Abu Dhabi Coast

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 985 ◽  
Author(s):  
Waleed Hamza ◽  
Letizia Lusito ◽  
Francesco Ligorio ◽  
Giuseppe Tomasicchio ◽  
Felice D’Alessandro
Keyword(s):  
Shallow Water ◽  
Numerical Models ◽  
Grid Point ◽  
Arabian Gulf ◽  
Acoustic Doppler Current Profiler ◽  
Wave Climate ◽  
Abu Dhabi ◽  
Water Conditions ◽  
Key Factor ◽  
Offshore Wave

High-resolution, reliable global atmospheric and oceanic numerical models can represent a key factor in designing a coastal intervention. At the present, two main centers have the capabilities to produce them: the National Oceanic and Atmospheric Administration (NOAA) in the U.S.A. and the European Centre for Medium-Range Weather Forecasts (ECMWF). The NOAA and ECMWF wave models are developed, in particular, for different water regions: deep, intermediate, and shallow water regions using different types of spatial and temporal grids. Recently, in the Arabian Gulf (also named Persian Gulf), the Abu Dhabi Municipality (ADM) installed an ADCP (Acoustic Doppler Current Profiler) to observe the atmospheric and oceanographic conditions (water level, significant wave height, peak wave period, water temperature, and wind speed and direction) at 6 m water depth, in the vicinity of the shoreline of the Saadiyat beach. Courtesy of Abu Dhabi Municipality, this observations dataset is available; the recorded data span the period from June 2015 to January 2018 (included), with a time resolution of 10 min and 30 min for the atmospheric and oceanographic variables, respectively. At the ADCP deployment location (ADMins), the wave climate has been determined using wave propagation of the NOAA offshore wave dataset by means of the Simulating WAves Nearshore (SWAN) numerical model, the NOAA and ECMWF wave datasets at the closest grid point in shallow water conditions, and the SPM ’84 hindcasting method with the NOAA wind dataset used as input. It is shown that the best agreement with the observed wave climate is obtained using the SPM ’84 hindcasting method for the shallow water conditions.

scholarly journals Kelvin wave hydraulic control induced by interactions between vortices and topography

2011 ◽  
Vol 687 ◽  
pp. 194-208 ◽  
Author(s):  
Andrew McC. Hogg ◽  
William K. Dewar ◽  
Pavel Berloff ◽  
Marshall L. Ward
Keyword(s):  
Shallow Water ◽  
Analytical Solutions ◽  
Critical Condition ◽  
Numerical Models ◽  
Kelvin Waves ◽  
Water Model ◽  
Hydraulic Jumps ◽  
Hydraulic Control ◽  
Kelvin Wave ◽  
Shallow Water Model

AbstractThe interaction of a dipolar vortex with topography is examined using a combination of analytical solutions and idealized numerical models. It is shown that an anticyclonic vortex may generate along-topography flow with sufficient speeds to excite hydraulic control with respect to local Kelvin waves. A critical condition for Kelvin wave hydraulic control is found for the simplest case of a 1.5-layer shallow water model. It is proposed that in the continuously stratified case this mechanism may allow an interaction between low mode vortices and higher mode Kelvin waves, thereby generating rapidly converging isopycnals and hydraulic jumps. Thus, Kelvin wave hydraulic control may contribute to the flux of energy from mesoscale to smaller, unbalanced, scales of motion in the ocean.

A Study of the Behaviour of a Single-Bladed Waste-Water Pump

2006 ◽  
Vol 220 (2) ◽  
pp. 79-87 ◽  
Author(s):  
J Keays ◽  
C Meskell
Keyword(s):  
Waste Water ◽  
Power Consumption ◽  
Turbulence Model ◽  
Numerical Models ◽  
Sewage Treatment ◽  
Computational Cost ◽  
Primary Source ◽  
Pressure Head ◽  
Primary Objective ◽  
Pump Efficiency

A single-vaned centrifugal pump, typical of the kind employed in waste-water applications (e.g. sewage treatment), has been investigated numerically. The primary objective was to identify a modelling approach that was accurate, but at an acceptable computational cost. A test program has been executed to provide data to validate the numerical models. The global performance of the pump was assessed in terms of the pressure head, the mass flowrate, the power consumption, and the pump efficiency. In addition, time-resolved surface-pressure measurements were made at the volute wall. Five combinations of three modelling approximations (two or 3D; k-ε or Reynolds stress model turbulence model; unsteady or quasi-steady) were investigated and compared with the experimental results. It was found that the choice of turbulence model did not have a significant effect on the predictions. In all cases, the head-discharge curve was well predicted. However, it was found that only the quasi-steady models could capture the trend of the power consumption curve, and hence that of the efficiency. Discrepancies in the magnitude of the power consumption can be accounted for by the lack of losses such as leakage in the numerical models. Qualitative analysis of the numerical results identifies the trailing edge of the impeller as the primary source of power loss, with the flow in the region of the cut water also contributing significantly to the poor overall efficiency of the design.

scholarly journals Assimilation of Lightning Data Using a Nudging Method Involving Low-Level Warming

2014 ◽  
Vol 142 (12) ◽  
pp. 4850-4871 ◽  
Author(s):  
Max R. Marchand ◽  
Henry E. Fuelberg
Keyword(s):  
Numerical Models ◽  
Deep Convection ◽  
Computational Cost ◽  
Wrf Model ◽  
Stage Iv ◽  
Simulated Precipitation ◽  
Synoptic Forcing ◽  
Total Lightning ◽  
Mu Method ◽  
Short Time

Abstract This study presents a new method for assimilating lightning data into numerical models that is suitable at convection-permitting scales. The authors utilized data from the Earth Networks Total Lightning Network at 9-km grid spacing to mimic the resolution of the Geostationary Lightning Mapper (GLM) that will be on the Geostationary Operational Environmental Satellite-R (GOES-R). The assimilation procedure utilizes the numerical Weather Research and Forecasting (WRF) Model. The method (denoted MU) warms the most unstable low levels of the atmosphere at locations where lightning was observed but deep convection was not simulated based on the absence of graupel. Simulation results are compared with those from a control simulation and a simulation employing the lightning assimilation method developed by Fierro et al. (denoted FO) that increases water vapor according to a nudging function that depends on the observed flash rate and simulated graupel mixing ratio. Results are presented for three severe storm days during 2011 and compared with hourly NCEP stage-IV precipitation observations. Compared to control simulations, both the MU and FO assimilation methods produce improved simulated precipitation fields during the assimilation period and a short time afterward based on subjective comparisons and objective statistical scores (~0.1, or 50%, improvement of equitable threat scores). The MU generally performs better at simulating isolated thunderstorms and other weakly forced deep convection, while FO performs better for the case having strong synoptic forcing. Results show that the newly developed MU method is a viable alternative to the FO method, exhibiting utility in producing thunderstorms where observed, and providing improved analyses at low computational cost.

scholarly journals AN EFFICIENT AND ROBUST GPGPU-BASED SHALLOW WATER MODEL

2020 ◽  
pp. 47
Author(s):  
Fatima-zahra Mihami ◽  
Volker Roeber
Keyword(s):  
Numerical Solution ◽  
Shallow Water ◽  
Computational Cost ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Water Model ◽  
Staggered Grid ◽  
Finite Volume Scheme ◽  
Flow Solver ◽  
Riemann Solvers

We present an efficient and robust numerical model for the solution of the Shallow Water Equations with the objective to develop the numerical foundation for an advanced free surface flow solver. The numerical solution is based on an explicit Finite Volume scheme on a staggered grid to ensure the conservation of mass and momentum across flow discontinuities and wet-dry transitions. This leads to an accurate numerical solution at low computational cost without the need for Riemann solvers. The efficiency of the lean numerical structure is further optimized through a CUDA-GPU implementation.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/xMnK_r7Tj1Q

scholarly journals MULTI-SCALE INFRA-GRAVITY WAVE DYNAMICS - THE FRENCH BASQUE COAST

2020 ◽  
pp. 46
Author(s):  
Volker Roeber ◽  
J. Dylan Nestler ◽  
Jonas Pinault ◽  
Assaf Azouri ◽  
Florian Bellafont
Keyword(s):  
Water Level ◽  
Gravity Wave ◽  
Numerical Study ◽  
Numerical Models ◽  
Wave Direction ◽  
Wave Dynamics ◽  
Multi Scale ◽  
Offshore Wave ◽  
A Site ◽  
Basque Coast

Phase-resolving numerical models are a powerful tool to identify and analyze dominant wave processes along a site of interest. We have carried out a numerical study related to infra-gravity wave dynamics along the French Basque coast. The computed scenarios are representative for the swell conditions at the site of interest and include variations in offshore wave height, direction, and water level. Several statistical methods were employed that illustrate that the irregular bathymetry is a key component for the strong variations in sea-swell and IG-wave energy. The water level is demonstrated to substantially affect the IG-wave behavior, more than the wave direction. Swash oscillations in the IG-frequency band are greater than or equal to sea-swell swash oscillations at nearly all locations along the studied shoreline.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/ELZwJCokkX0

scholarly journals rpe v5: An emulator for reduced floating-point precision in large numerical simulations

2016 ◽  
Author(s):  
Andrew Dawson ◽  
Peter Düben
Keyword(s):  
Numerical Simulations ◽  
Climate Models ◽  
Numerical Models ◽  
Computational Cost ◽  
Floating Point ◽  
Climate Modelling ◽  
Acceptable Quality ◽  
Weather And Climate ◽  
Code Changes ◽  
Numerical Precision

Abstract. This paper describes the rpe library which has the capability to emulate the use of arbitrary reduced floating-point precision within large numerical models written in Fortran. The rpe software allows model developers to test how reduced floating-point precision affects the result of their simulations without having to make extensive code changes or port the model onto specialised hardware. The software can be used to identify parts of a program that are problematic for numerical precision and to guide changes to the program to allow a stronger reduction in precision. The development of rpe was motivated by the strong demand for more computing power. If numerical precision can be reduced for an application under consideration while still achieving results of acceptable quality, computational cost can be reduced, since a reduction in numerical precision may allow an increase in performance or a reduction in power consumption. For simulations with weather and climate models, savings due to a reduction in precision could be reinvested to allow model simulations at higher spatial resolution or complexity, or to increase the number of ensemble members to improve predictions. rpe was developed with particular focus on the community of weather and climate modelling, but the software could be used with numerical simulations from other domains.

scholarly journals Wave Propagation in Thin-Walled Aortic Analogues

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
C. G. Giannopapa ◽  
J. M. B. Kroot ◽  
A. S. Tijsseling ◽  
M. C. M. Rutten ◽  
F. N. van de Vosse
Keyword(s):  
Experimental Data ◽  
Wave Propagation ◽  
Frequency Domain ◽  
Analytical Model ◽  
Viscoelastic Properties ◽  
Numerical Models ◽  
Computational Cost ◽  
One Dimensional ◽  
Arterial Blood

Research on wave propagation in liquid filled vessels is often motivated by the need to understand arterial blood flows. Theoretical and experimental investigation of the propagation of waves in flexible tubes has been studied by many researchers. The analytical one-dimensional frequency domain wave theory has a great advantage of providing accurate results without the additional computational cost related to the modern time domain simulation models. For assessing the validity of analytical and numerical models, well defined in vitro experiments are of great importance. The objective of this paper is to present a frequency domain analytical model based on the one-dimensional wave propagation theory and validate it against experimental data obtained for aortic analogs. The elastic and viscoelastic properties of the wall are included in the analytical model. The pressure, volumetric flow rate, and wall distention obtained from the analytical model are compared with experimental data in two straight tubes with aortic relevance. The analytical results and the experimental measurements were found to be in good agreement when the viscoelastic properties of the wall are taken into account.

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