Liu Liqi¹, Wang Haitao^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.4, pp. 303-324, 2015, DOI:10.3970/cmes.2015.109.303

Abstract This paper presents a three-dimensional (3-D) boundary element method (BEM) scheme based on the Radial Integration Method (RIM) for wave propagation analysis of continuously non-homogeneous problems. The Kelvin fundamental solutions are adopted to derive the boundary-domain integral equation (BDIE). The RIM proposed by Gao (Engineering Analysis with Boundary Elements 2002; 26(10):905-916) is implemented to treat the domain integrals in the BDIE so that only boundary discretization is required. After boundary discretization, a set of second-order ordinary differential equations with respect to time variable are derived, which are solved using the Wilson-q method. Main advantages of the proposed method are that… More >

Zilong Zhang¹, Yajun Yin², Zheng Zhong^1,3, Hongxiao Zhao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.3, pp. 285-302, 2015, DOI:10.3970/cmes.2015.109.285

Abstract Dragonflies possess the highly corrugated wings which distinguish from the ordinary airfoils. To unlock the secrets of the dramatic flight ability of dragonflies, it will be of great significance to investigate the aerodynamic contribution of the corrugations. In this paper, a group of corrugated airfoils were specially designed based on the geometrical characteristics of a typical dragonfly wing. The two-dimensional Navier-Stokes equations were solved using the finite volume method, and the coefficients of lift and drag of the studied airfoils were calculated and compared with those of a flat airfoil and a NACA0008 airfoil. The obtained numerical results illustrated that… More >

Chung-Fu Chen¹, Yi-Chia Cheng¹, Che-Wun Hong^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.3, pp. 263-283, 2015, DOI:10.3970/cmes.2015.109.263

Abstract Based on the Hellmann-Feynman theorem, which integrates the molecular dynamics simulation with computational quantum mechanics, this research simulates the ionic transport in the LiCl-KCl molten salt materials using so called “first principles molecular dynamics (FPMD)” technique without employing an empirical potential model. The main purpose of this computational FPMD focuses on the evaluation of important transport properties, such as diffusion coefficient, ionic conductivity, shear viscosity, and thermal conductivity, using the Green-Kubo relationship. All simulation results agree well with experimental data published in existing literatures within an acceptable range. FPMD calculations are proved to be a powerful tool for prediction of… More >

S. Vahdati¹, D. Mirzaei²

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.3, pp. 247-262, 2015, DOI:10.3970/cmes.2015.109.247

Abstract In this paper we present a meshless collocation method based on the moving least squares (MLS) approximation for numerical solution of the multiasset (d-dimensional) American option in financial mathematics. This problem is modeled by the Black-Scholes equation with moving boundary conditions. A penalty approach is applied to convert the original problem to one in a fixed domain. In finite parts, boundary conditions satisfy in associated (d-1)-dimensional Black-Scholes equations while in infinity they approach to zero. All equations are treated by the proposed meshless approximation method where the method of lines is employed for handling the time variable. Numerical examples for… More >

Hui Yin¹, Dejie Yu^1,2, Shengwen Yin¹, Baizhan Xia¹

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.3, pp. 221-246, 2015, DOI:10.3970/cmes.2015.109.221

Abstract This paper presents a new hybrid Chebyshev-perturbation method (HCPM) for the prediction of acoustic field with random and interval parameters. In HCPM, the perturbation method based on the first-order Taylor series that accounts for the random uncertainty is organically integrated with the first-order Chebyshev polynomials that deal with the interval uncertainty; specifically, a random interval function is firstly expanded with the first-order Taylor series by treating the interval variables as constants, and the expressions of the expectation and variance can be obtained by using the random moment method; then the expectation and variance of the function are approximated by using… More >

M. Pastor¹, T. Blanc¹, V. Drempetic¹ , P. Dutto¹ , M. Martín Stickle¹, A.Yagüe¹

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.2, pp. 183-220, 2015, DOI:10.3970/cmes.2015.109.183

Abstract This paper presents a model (mathematical, rheological and numerical) for triggering and propagation of landslides presenting coupling between the solid skeleton and the pore fluid. The model consists of two sub models, a depth integrated model incorporating the propagation equations, and a 1D model describing pore pressure evolution. The depth integrated sub model is discretized using a set of SPH nodes, each one having an associated finite difference mesh for discretizing the pore pressure evolution. The model we propose differs from other depth integrated models with coupled pore pressures proposed in the past in the way pore pressures are described… More >

S. Freire¹, D. Ehrlich¹, S. Ferri¹

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.2, pp. 159-182, 2015, DOI:10.3970/cmes.2015.109.159

Abstract Media and specialized scientific literature are often addressing the “increasing impact and ensuing damages due to natural hazards”. It is frequently argued that a rising frequency and intensity of hazards is responsible for the increase in losses. The role of increasing population exposure due to phenomenal population growth, or urbanization as a driver of risk is still insufficiently addressed. We investigate spatio-temporal changes in population exposure to seismic hazard and their role on impacts from earthquakes in the XX century. Spatial analysis is used to study historical population distributions in relation to seismic intensity, at the global and continental levels.… More >

Riitta Molarius¹, Pekka Tuomaala¹, Kalevi Piira¹, Minna Räikkönen¹, Christoph Aubrecht², Maria Polese³, Giulio Zuccaro^3,4, KaroliinaPilli-Sihvola⁵, Kalev Ranna

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.2, pp. 131-158, 2015, DOI:10.3970/cmes.2015.109.131

Abstract In northern regions, society can be seriously interrupted by a prolonged electricity network blackout due to a winter storm that cuts off power, communication and road networks. Due to hard winter weather it is essential to enhance the resilience of society to avoid danger to life. This can be achieved by developing new models to enhance preparedness for coming disaster events and to support rescue and other authorities to focus their resources on the most vulnerable targets in actual cases of emergencies. This paper presents a part of the results of activities performed within the EU project ‘CRISMA – Modelling… More >

R. Rongo^1,2, D. D’Ambrosio^1,2, G. Iovine^2,3, F. Lucà⁴, V. Lupiano⁵, V.P.Boñgolan⁶, W. Spataro^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.2, pp. 105-130, 2015, DOI:10.3970/cmes.2015.109.105

Abstract Determining sectors that could be affected by lava flows in volcanic areas is essential for risk mitigation purposes. Traditionally, when adopting methods based on probabilistic numerical simulations, the hazard is assessed by analysing a huge set of simulations of hypothetical events, each characterized by a distinct probability of occurrence based on statistics of historical events. If lateral or eccentric eruptions are also taken into account, simulated lava flows usually start from the nodes of regular grids of potential vents, uniformly covering the study area. In this study, an alternative approach to evaluate flow-type hazard, based on a nonuniform grid of… More >

P. Costabile¹, F. Macchione¹, L. Natale², G. Petaccia²

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.2, pp. 81-103, 2015, DOI:10.3970/cmes.2015.109.081

Abstract In this paper the impact induced by bridges on the river flow is studied applying 1-D and 2-D unsteady flow models. Both the models are based on the Shallow Water Equations written in conservative form and solved with first order upwind schemes. In particular, the effect of bridges on the flow behavior simulated by the models is discussed from a practical point of view, with reference to the longitudinal and cross-section water surface profiles. Two cases characterized by bridges perpendicular to the principle flow direction are presented. The bridges are located in almost rectilinear river reaches whose cross-sections are confined… More >