scholarly journals INTER-COUPLED TSUNAMI MODELLING THROUGH AN ABSORBING-GENERATING BOUNDARY

2020 ◽  
pp. 38
Author(s):  
Sangyoung Son ◽  
Patrick Lynett
Keyword(s):  
Shallow Water ◽  
Shallow Water Equation ◽  
Boussinesq Equations ◽  
Equation Model ◽  
Water Model ◽  
Navier Stokes ◽  
Characteristic Form ◽  
Computationally Efficient ◽  
Boussinesq Model ◽  
Tsunami Modelling

For many practical and theoretical purposes, various types of tsunami wave models have been developed and utilized so far. Some distinction among them can be drawn based on governing equations used by the model. Shallow water equations and Boussinesq equations are probably most typical ones among others since those are computationally efficient and relatively accurate compared to 3D Navier-Stokes models. From this idea, some coupling effort between Boussinesq model and shallow water equation model have been made (e.g., Son et al. (2011)). In the present study, we couple two different types of tsunami models, i.e., nondispersive shallow water model of characteristic form(MOST ver.4) and dispersive Boussinesq model of non-characteristic form(Son and Lynett (2014)) in an attempt to improve modelling accuracy and efficiency.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/cTXybDEnfsQ

scholarly journals An improved shallow water equation model for water animation

2017 ◽  
Author(s):  
Mingjing Ai ◽  
Anding Du ◽  
Han Xu ◽  
Jianwei Niu
Keyword(s):  
Shallow Water ◽  
Shallow Water Equation ◽  
Equation Model

scholarly journals The shape of submarine levees: exponential or power law?

2009 ◽  
Vol 619 ◽  
pp. 367-376 ◽  
Author(s):  
V. K. BIRMAN ◽  
E. MEIBURG ◽  
B. KNELLER
Keyword(s):  
Steady State ◽  
Shallow Water ◽  
Power Law ◽  
Sediment Supply ◽  
Water Model ◽  
Navier Stokes ◽  
Entrainment Rate ◽  
Quasi Steady State ◽  
Shallow Water Model ◽  
Power Law Decay

Field observations indicate that the height of submarine levees decays with distance from the channel either exponentially or according to a power law. This investigation clarifies the flow conditions that lead to these respective shapes, via a shallow water model for the overflow currents that govern the levee formation. The model is based on a steady state balance of sediment supply by the turbidity current, and sediment deposition onto the levee, with the settling velocity and the entrainment rate appearing as parameters. It demonstrates that entrainment of ambient fluid is the determining factor for the levee shape. For negligible entrainment rates, levee shapes tend to exhibit exponential profiles, while constant rates of entrainment or detrainment result in power law shapes. Interestingly, whether a levee has an exponential or a power law shape is determined by kinematic considerations only, viz. the balance laws for sediment mass and fluid volume. We find that the respective coefficients governing the exponential or power law decay depend on the settling speeds of the sediment grains, which in turn is a function of the grain size. Two-dimensional, unsteady Navier–Stokes simulations confirm the emergence of a quasi-steady state. The depositional behaviour of this quasi-steady state is consistent with the predictions of the shallow water model, thus validating the assumptions underlying the model, and demonstrating its predictive abilities.

scholarly journals Fast Spherical Harmonic Transform Routine FLTSS Applied to the Shallow Water Test Set

2005 ◽  
Vol 133 (3) ◽  
pp. 634-648 ◽  
Author(s):  
Reiji Suda
Keyword(s):  
Computational Complexity ◽  
Shallow Water ◽  
Spherical Harmonic ◽  
Numerical Solutions ◽  
Shallow Water Equation ◽  
Approximate Algorithm ◽  
Water Model ◽  
Legendre Transform ◽  
Test Set ◽  
Spectral Transform

Abstract The fast spherical harmonic transform algorithm proposed by Suda and Takami is evaluated in the solutions of the shallow water equation test set defined by Williamson et al. through replacing the Legendre transforms of the NCAR spectral transform shallow water model (STSWM) with routines of the fast Legendre transform with stable sampling (FLTSS), which is the first implementation of the Suda–Takami algorithm. The Suda–Takami algorithm is an approximate algorithm with the computational complexity O(T 2 log T log ɛ−1), with T being the maximum wavenumber and ɛ the accuracy parameter of the FLTSS. The influence of the approximation errors of the FLTSS upon the numerical solutions is investigated. For all test cases of the Williamson et al. test set, the FLTSS stably solved the equations with the results that can be explained well with the accuracy ɛ. The stability in longer time integrations is also assessed, where test case 7 of an analyzed atmospheric initial condition was stably integrated for 1 yr. The FLTSS was faster than the STSWM at T170 and had higher resolutions on an Intel Mobile Pentium 4, where the lower space complexity (memory requirements) of the FLTSS was advantageous in addition to the lower computational complexity.

A NUMERICAL STUDY OF DAM-BREAK FLOW AND SEDIMENT TRANSPORT FROM A QUAKE LAKE

2011 ◽  
Vol 05 (05) ◽  
pp. 401-428 ◽  
Author(s):  
PENGZHI LIN ◽  
YINNA WU ◽  
JUNLI BAI ◽  
QUANHONG LIN
Keyword(s):  
Sediment Transport ◽  
Shallow Water ◽  
High Speed ◽  
Numerical Study ◽  
Shallow Water Equation ◽  
Equation Model ◽  
Dam Break ◽  
Bed Morphology ◽  
Dam Break Flow ◽  
Quake Lake

Dam-break flows are simulated numerically by a two-dimensional shallow-water-equation model that combines a hydrodynamic module and a sediment transport module. The model is verified by available analytical solutions and experimental data. It is demonstrated that the model is a reliable tool for the simulation of various transient shallow water flows and the associated sediment transport and bed morphology on complex topography. The validated model is then applied to investigate the potential dam-break flows from Tangjiashan Quake Lake resulting from Wenchuan Earthquake in 2008. The dam-break flow evolution is simulated by using the model in order to provide the flooding patterns (e.g., arrival time and flood height) downstream. Furthermore, the sediment transport and bed morphology simulation is performed locally to study the bed variation under the high-speed dam-break flow.

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