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    Impulse waves effects on coastlines and onshore industrial structures

    , Article Proceedings of the 5th International Conference on Asian and Pacific Coasts, APAC 2009, 13 October 2009 through 16 October 2009 ; Volume 4 , 2010 , Pages 29-36 ; 9789814466561 (ISBN) Najafi Jilani, A ; Ataie Ashtiani, B ; Sharif University of Technology
    Abstract
    Laboratory investigations have been performed on impulse wave's effects near the coastlines such as shoaling effects and run-up. Wave run-up over on smooth impermeable slope are studied in over than 100 experimental tests. The influences of the bed slope angle, incident impulse wave height and still water depth are investigated. The available empirical equations for impulsive wave run-up have been examined by comparison with the collected experimental data. A new equation has been presented for run-up estimation based on the laboratory measurements. It has been compared with others empirical equations and the differences have been discussed. The shoaling effects on the impulse wave feature... 

    Modification of compressible smooth particles hydrodynamics for angular momentum in simulation of impulsive wave problems

    , Article Prediction and Simulation Methods for Geohazard Mitigation - Proceedings of the International Symposium on Prediction and Simulation Methods for Geohazard Mitigation, IS-KYOTO 2009, 25 May 2009 through 27 May 2009 ; 2009 , Pages 201-206 ; 9780415804820 (ISBN) Mansour Rezaei, S ; Ataie Ashtiani, B ; Sharif University of Technology
    Abstract
    In this work, Compressible Smooth Particles Hydrodynamics (C-SPH) is applied for numerical simulation of impulsive wave. Properties of linear and angular momentum in SPH formulation are studied. Kernel gradient of viscous term in momentum equation is corrected to ensure preservation of angular momentum. Corrected SPH method is used to simulate solitary Scott Russell wave and applied to simulate impulsive wave generated by two-dimensional under water landslide. In each of test cases, results of corrected SPH are compared with experimental results. The results of the numerical simulations and experimental works are matched and a satisfactory agreement is observed. Furthermore, vorticity... 

    Numerical simulation of landslide impulsive waves by incompressible smoothed particle hydrodynamics

    , Article International Journal for Numerical Methods in Fluids ; Volume 56, Issue 2 , 2008 , Pages 209-232 ; 02712091 (ISSN) Ataie Ashtiani, B ; Shobeyri, G ; Sharif University of Technology
    2008
    Abstract
    An incompressible-smoothed particle hydrodynamics (I-SPH) formulation is presented to simulate impulsive waves generated by landslides. The governing equations, Navier-Stokes equations, are solved in a Lagrangian form using a two-step fractional method. Landslides in this paper are simulated by a submerged mass sliding along an inclined plane. During sliding, both rigid and deformable landslides mass are considered. The present numerical method is examined for a rigid wedge sliding into water along an inclined plane. In addition solitary wave generated by a heavy box falling inside water, known as Scott Russell wave generator, which is an example for simulating falling rock avalanche into... 

    A method for modeling power transformer tap winding for transient studies

    , Article Conference Record of IEEE International Symposium on Electrical Insulation, Indianapolis, IN, 19 September 2004 through 22 September 2004 ; 2004 , Pages 34-37 ; 01642006 (ISSN) Naderi, M. S ; Vakilian, M ; Sharif University of Technology
    2004
    Abstract
    One of the challenges a transformer designer is faced with is to correctly model the different types of transformer windings for transient study. For a precise insulation design, determination of transformer transient responses is unavoidable. The basis of these studies is calculation of transient responses due to application of standard switching and lightning impulse wave to the transformer winding. In a previous work, a computer program was developed for determination of the layer and disk type windings transient model parameters based on design data. This program has all of the necessary capabilities for a detailed transient study. As a continuation of that work, in this paper a method... 

    A rigorous finite volume model to simulate subaerial and submarine landslide-generated waves

    , Article Landslides ; 2015 , Pages 1-19 ; 1612510X (ISSN) Yavari Ramshe, S ; Ataie Ashtiani, B ; Sharif University of Technology
    Springer Verlag  2015
    Abstract
    This paper presents a new landslide-generated wave (LGW) model based on incompressible Euler equations with Savage-Hutter assumptions. A two-layer model is developed including a layer of granular-type flow beneath a layer of an inviscid fluid. Landslide is modeled as a two-phase Coulomb mixture. A well-balanced second-order finite volume formulation is applied to solve the model equations. Wet/dry transitions are treated properly using a modified non-linear method. The numerical model is validated using two sets of experimental data on subaerial and submarine LGWs. Impulsive wave characteristics and landslide deformations are estimated with a computational error less than 5 %. Then, the... 

    Simulation of wave generated by landslides in Maku dam reservoir

    , Article Prediction and Simulation Methods for Geohazard Mitigation - Proceedings of the International Symposium on Prediction and Simulation Methods for Geohazard Mitigation, IS-KYOTO 2009, 25 May 2009 through 27 May 2009 ; 2009 , Pages 91-96 ; 9780415804820 (ISBN) Yavari Ramshe, S ; Ataie Ashtiani, B ; Sharif University of Technology
    Abstract
    In this work, impulsive wave generation and propagation generated by landslides are studied numerically for a real case. Maku dam reservoir, in the northwestern of Iran is considered as the case study. Generated wave heights, wave run-up, maximum wave height above the dam crest and the probable overtopping volume have been evaluated, using a two-dimensional numerical model (LS3D). This model is validated using available three-dimensional experimental data for simulating impulsive wave caused by sub-aerial landslides. Based on the results, the generated wave height for first and second scenarios are 12 m and 18 m respectively. The wave height of 8 m is observed close to dam body. Because of... 

    Modification of weakly compressible smoothed particle hydrodynamics for preservation of angular momentum in simulation of impulsive wave problems

    , Article Coastal Engineering Journal ; Volume 51, Issue 4 , 2009 , Pages 363-386 ; 05785634 (ISSN) Ataie Ashtiani, B ; Mansour Rezaei, S ; Sharif University of Technology
    Abstract
    In this work, Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) is applied for numerical simulation of impulsive wave. Properties of linear and angular momentum in WCSPH formulation are studied. Kernel gradient of viscous term in momentum equation is corrected to ensure preservation of angular momentum. Corrected WCSPH method is used to simulate solitary Scott Russell wave and applied to simulate impulsive wave generated by two-dimensional under water landslide. In each of the test cases, results of corrected WCSPH are compared with experimental results. The results of the numerical simulations and experimental works are matched and a satisfactory agreement is observed.... 

    Laboratory investigations on impulsive waves caused by underwater landslide

    , Article Coastal Engineering ; Volume 55, Issue 12 , December , 2008 , Pages 989-1004 ; 03783839 (ISSN) Ataie Ashtiani, B ; Najafi Jilani, A ; Sharif University of Technology
    2008
    Abstract
    Laboratory investigations have been performed on the submarine landslide generated waves by performing 120 laboratory tests. Both rigid and deforming-slide masses are considered. The effects of bed slope angle, initial submergence, slide geometry, shape and deformation on impulse wave characteristics have been inspected. Impulse wave amplitude, period, energy and nonlinearity are studied in this work. The effects of bed slope angle on energy conversion from slide into wave are also investigated. Laboratory-based prediction equations are presented for impulse wave amplitude and period in near and far-field and are successfully verified using the available data in previous laboratory and... 

    Estimation of near-field characteristics of tsunami generation by submarine landslide

    , Article Ocean Engineering ; Volume 35, Issue 5-6 , 2008 , Pages 545-557 ; 00298018 (ISSN) Najafi Jilani, A ; Ataie Ashtiani, B ; Sharif University of Technology
    2008
    Abstract
    Underwater landslide can trigger impulsive waves with high amplitude and run-up, which may cause substantial damage. In this work, the experimental investigations are performed to study the impulsive wave characteristics caused by underwater landslides. The effects of landslide geometry and kinematics on wave characteristics are studied by performing 84 laboratory experiments. The influences of thickness, volume and shape of failure mass on the characteristics of initial wave are discussed. The impacts of water body conditions such as the slope of sliding bed and the initial submergence of underwater landslide are also examined. The present experimental data as well as the available data in... 

    A higher-order Boussinesq-type model with moving bottom boundary: Applications to submarine landslide tsunami waves

    , Article International Journal for Numerical Methods in Fluids ; Volume 53, Issue 6 , 2007 , Pages 1019-1048 ; 02712091 (ISSN) Ataie Ashtiani, B ; Najafi Jilani, A ; Sharif University of Technology
    2007
    Abstract
    A two-dimensional depth-integrated numerical model is developed using a fourth-order Boussinesq approximation for an arbitrary time-variable bottom boundary and is applied for submarine-landslide-generated waves. The mathematical formulation of model is an extension of (4,4) Padé approximant for moving bottom boundary. The mathematical formulations are derived based on a higher-order perturbation analysis using the expanded form of velocity components. A sixth-order multi-step finite difference method is applied for spatial discretization and a sixth-order Runge-Kutta method is applied for temporal discretization of the higher-order depth-integrated governing equations and boundary... 

    Numerical modeling of subaerial and submarine landslide-generated tsunami waves—recent advances and future challenges

    , Article Landslides ; Volume 13, Issue 6 , 2016 , Pages 1325-1368 ; 1612510X (ISSN) Yavari Ramshe, S ; Ataie Ashtiani, B ; Sharif University of University
    Springer Verlag 
    Abstract
    Landslide-generated waves (LGWs) are among natural hazards that have stimulated attentions and concerns of engineers and researchers during the past decades. At the same period, the application of numerical modeling has been progressively increased to assess, control, and manage the risks of such hazards. This paper represents an overview of numerical studies on LGWs to explore associated recent advances and future challenges. In this review, the main landslide events followed by an LGW hazard are scrutinized. The uncertainty regarding landslide characteristics and the lack of data concerning generated tsunami properties highlights the necessity of probabilistic analysis and numerical... 

    A rigorous finite volume model to simulate subaerial and submarine landslide-generated waves

    , Article Landslides ; Volume 14, Issue 1 , 2017 , Pages 203-221 ; 1612510X (ISSN) Yavari Ramshe, S ; Ataie Ashtiani, B ; Sharif University of Technology
    Springer Verlag  2017
    Abstract
    This paper presents a new landslide-generated wave (LGW) model based on incompressible Euler equations with Savage-Hutter assumptions. A two-layer model is developed including a layer of granular-type flow beneath a layer of an inviscid fluid. Landslide is modeled as a two-phase Coulomb mixture. A well-balanced second-order finite volume formulation is applied to solve the model equations. Wet/dry transitions are treated properly using a modified non-linear method. The numerical model is validated using two sets of experimental data on subaerial and submarine LGWs. Impulsive wave characteristics and landslide deformations are estimated with a computational error less than 5 %. Then, the... 

    Numerical simulation of wave generated by landslide incidents in dam reservoirs

    , Article Landslides ; Volume 8, Issue 4 , 2011 , Pages 417-432 ; 1612510X (ISSN) Ataie Ashtiani, B ; Yavari Ramshe, S ; Sharif University of Technology
    2011
    Abstract
    In this work, a two-dimensional fourth-order Boussinesq-type numerical model is applied to estimate the impact of landslide-generated waves in dam reservoirs. This numerical model has recently been extended for simulating subaerial landslides. The extended model is validated using available three-dimensional experimental data, and a good agreement is obtained. The numerical model is then employed to investigate the impact of landslide-generated waves in two real cases, the Maku and Shafa-Roud dam reservoirs in the northwestern and the north of Iran, respectively. Generated wave heights, wave run-up, maximum wave height above dam crest, and dam overtopping volume have been estimated for each...