the numerical solution of hyperbolic second-order wave equations is of fundamental importance to the simulation of time dependent acoustic, electromagnetic of elastic wave prop-agation phenomena. In this work we study...
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ISBN:
(纸本)9783950353709
the numerical solution of hyperbolic second-order wave equations is of fundamental importance to the simulation of time dependent acoustic, electromagnetic of elastic wave prop-agation phenomena. In this work we study numerically higher order continuous and discon-tinuous finite element approximations of the acoustic and elastic wave equation. In particular, the ability of the discretization schemes to simulate accurately waves in heterogeneous media is analyzed. the efficient parallel implementation of the algorithms is addressed further.
Economic demands for fuel efficiency on the one hand and regulatory requirements for reduction of emissions on the other hand lead to highly complex propulsion systems in the commercial vehicle area. Conventional deve...
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ISBN:
(纸本)9783950353709
Economic demands for fuel efficiency on the one hand and regulatory requirements for reduction of emissions on the other hand lead to highly complex propulsion systems in the commercial vehicle area. Conventional development methods reach there limits at the layout of such systems. the present work shows an integrated model which represents a detailed engine model including predictive Diesel combustion and an aftertreatment system with reaction kinetics. this model can be used for determining overall system behavior in transient cycles and builds the basis for numerical optimization.
After a short introduction and main issues associated with inverse problem, three examples are chosen to illustrate the application of Artificial Neural Networks in the inverse problems solution. For a steady state co...
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ISBN:
(纸本)9783950353709
After a short introduction and main issues associated with inverse problem, three examples are chosen to illustrate the application of Artificial Neural Networks in the inverse problems solution. For a steady state convection problem, assuming given concentration field values in a few measurement points and values of hydraulic head in the same piezometers, the source of the concentration and its intensity are deduced using Artificial Neural Networks (ANNs). the same method is used for identification of diffusivity vector. To illustrate the reliability of the procedure, the case of randomly perturbed data is presented. the main conclusion states that the soft method seems to be very automatic and convenient in solving a large family of inverse problems.
numerical experiments suggest the interesting properties in the several fields. In the flow through an absorbing medium, an interaction between nonlinear diffusion and penetration from the boundary causes an interesti...
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ISBN:
(纸本)9783950353709
numerical experiments suggest the interesting properties in the several fields. In the flow through an absorbing medium, an interaction between nonlinear diffusion and penetration from the boundary causes an interesting dynamical behaviour of support;that is, "support splitting phenomena", "support splitting and merging phenomena", and "repeated support splitting and merging phenomena" may be observed. Here the support means the region occupied by the fluid. In this paper these phenomena are realized and justified from numerical and mathematical points of view in nonlinear initial-boundary value problem for a porous media equation with absorption.
the numerical simulation of the biaxial bulge test with circular die was performed with help of the in-house code DD3IMP, in order to characterize the plastic behaviour of sheet metals. the methodology for determining...
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ISBN:
(纸本)9783950353709
the numerical simulation of the biaxial bulge test with circular die was performed with help of the in-house code DD3IMP, in order to characterize the plastic behaviour of sheet metals. the methodology for determining the hardening law used in the experimental determination, with recourse to the membrane theory, and the errors associated with such determination, were studied by numerical simulation. the study was carried out on anisotropic metal sheets, with or without isotropy in the sheet plane. the numerical variables such as strain paths, strain values, pressure, curvature and thickness at the pole were analysed.
the numerical modeling of coupled elastic-acoustic wave problems is a topic of increasing interest in many fields of computational physics and engineering. However, the modeling of wave propagation in complex geometri...
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ISBN:
(纸本)9783950353709
the numerical modeling of coupled elastic-acoustic wave problems is a topic of increasing interest in many fields of computational physics and engineering. However, the modeling of wave propagation in complex geometries is a difficult task. Promising candidates for accurately approximating underwater acoustic problems with a reduced computational cost are studied in this work. Namely these methods are the high-order discontinuous Galerkin withthe low-storage Runge-Kutta time-stepping scheme for the time-domain problems and the ultra weak variational formulation for the approximations that are computed in the frequency-domain. As the numerical experiment, we study acoustic scattering from cylindrical shaped elastic objects placed on the water/sediment interface.
Hierarchy experimental validation is a fundamental process for model Verification and Validation (V&V) in numerical simulations of complex engineering structures. thus the major uncertain factors are necessary to ...
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ISBN:
(纸本)9783950353709
Hierarchy experimental validation is a fundamental process for model Verification and Validation (V&V) in numerical simulations of complex engineering structures. thus the major uncertain factors are necessary to be found for experiment design. this study performs a sensitivity analysis for hierarchy experimental validation of a typical complex engineering structure which includes bolt joints and rubber isolators. the influences of the uncertain factors, including loading parameters, structural sizes, behaviors of materials, properties of rubber isolators, and stiffness of bolt joints, are investigated by numerical simulations. then the major uncertain factors are found, which provides guidelines for designing experiments and measurements.
numerical computations of two-phase flows with surface active agents (surfactants) are highly demanded in several scientific and engineering applications. Apart from the other challenges associated withthe computatio...
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ISBN:
(纸本)9783950353709
numerical computations of two-phase flows with surface active agents (surfactants) are highly demanded in several scientific and engineering applications. Apart from the other challenges associated withthe computation of two-phase flows, the presence of surfactants increases the complexity. Surfactants alter the flow dynamics significantly by lowering the surface tension on the interface. Moreover, the concentration of surfactants along the interface is often not uniform and thus Marangoni forces are induced. Adsorption and desorption of surfactants between the interface and the bulk phase may take place in the case of soluble surfactants.
the Boundary Integral Method (BIM) is applied to investigate the dynamics of a single drop in isoviscous shear flow. the novelty of this work compared to the previous studies in this field is the application of Isogeo...
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ISBN:
(纸本)9783950353709
the Boundary Integral Method (BIM) is applied to investigate the dynamics of a single drop in isoviscous shear flow. the novelty of this work compared to the previous studies in this field is the application of Isogeometric Analysis (IGA) to define the interface of the drop. Singularity subtraction is applied for efficient numerical integration. Excellent agreement between the current results and the traditional BIM is observed. the approximation properties of the spline representation of the drop interface are studied both for the initial configuration and for the motion of the interface.
the Burger's-Fisher equation appears in different fields of applied sciences and physical applications. the Adomian decomposition method (ADM) for Burger's-Fisher equation was introduced in [1, 2]. the purpose...
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ISBN:
(纸本)9783950353709
the Burger's-Fisher equation appears in different fields of applied sciences and physical applications. the Adomian decomposition method (ADM) for Burger's-Fisher equation was introduced in [1, 2]. the purpose of this paper is to improve numerical solution of the problems given and solved by ADM in [1] and solution given in [3] according the note given in [4] and formulation given in [5]. the calculated results with just first two terms in series decomposition show the improvement in efficiency and accuracy with presented algorithm.
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