Surkay D. Akbarov^1,2,3, Panakh G. Panakhlı⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.2, pp. 89-112, 2015, DOI:10.3970/cmes.2015.108.089

Abstract The discrete-analytical solution method is proposed for the solution to problems related to the dynamics of the hydro-elastic system consisting of an axially-moving pre-stressed plate, compressible viscous fluid and rigid wall. The fluid flow caused by the axial movement of the plate and the pre-stresses in the plate are taken into consideration as the initial state of the system under consideration. It is assumed that the additional lineally-located time-harmonic forces act on the plate and these forces cause additional flow field in the fluid and an additional stress-strain state in the plate. The additional stress-strain… More >

Letícia Fleck Fadel Miguel¹, Leandro Fleck Fadel Miguel², João Kaminski Jr.³

CMES-Computer Modeling in Engineering & Sciences, Vol.104, No.2, pp. 87-104, 2015, DOI:10.3970/cmes.2015.104.086

Abstract Since the half of the XX century, attention was given to the instability of structures under parametric excitation, especially under periodic loads. On the other hand, the instability of bars subjected to axial loads of impulsive type has been little studied, in spite of the practical importance of the topic. Thus, in Engineering Design it is frequently supposed, without tests or additional verifications, that an axial load of short duration can exceed the Euler critical load of the bar without inducing damage in the same.
Within this context, this paper proposes the use of the… More >

Eduardo M. B. Campello^1,2, Tarek I. Zohdi³

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.2, pp. 221-245, 2014, DOI:10.3970/cmes.2014.098.221

Abstract This work deals with the bombardment of a stream of particles possessing varying mean particle size, velocity and aspect ratio into a cell that has fixed (known) compliance characteristics. The particles are intended to penetrate the cell membrane causing zero or minimum damage and deliver foreign substances (which are attached to their surfaces) to the interior of the cell. We adopt a particle-based (discrete element method) computational model that has been recently developed by the authors to describe both the incoming stream of particles and the cell membrane. By means of parametric numerical simulations, treating… More >

J.B. Alford¹, D.C. Simkins¹, R.A. Rembert¹, L. Hoyte, MD²

CMES-Computer Modeling in Engineering & Sciences, Vol.98, No.2, pp. 129-149, 2014, DOI:10.3970/cmes.2014.098.129

Abstract Mechanical deformation of tissues in the female pelvic floor is believed to be central to understanding a number of important aspects of women’s health, particularly pelvic floor dysfunction. A 2008 study of US women reported the prevalence of pelvic floor disorders in the 20 and 39 years range as 9.7% with the prevalence increasing with age until it reaches roughly 50% in the 80 and older age group [Nygaard, Barber, Burgio, and et al (2008)]. Clinical observation indicates a strong correlation between problems such as pelvic organ prolapse/urinary incontinence and vaginal childbirth. It is thought… More >

K.P. Baxevanakis¹, A.E. Giannakopoulos²

CMES-Computer Modeling in Engineering & Sciences, Vol.97, No.6, pp. 535-544, 2014, DOI:10.3970/cmes.2014.097.535

Abstract This article has no abstract. More >

Zichun Yang^1,2,3, Lei Zhang^1,4, Yueyun Cao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.97, No.2, pp. 101-130, 2014, DOI:10.3970/cmes.2014.097.101

Abstract Discretization of inverse problems often leads to systems of linear equations with a highly ill-conditioned coefficient matrix. To find meaningful solutions of such systems, one kind of prevailing and representative approaches is the so-called regularized total least squares (TLS) method when both the system matrix and the observation term are contaminated by some noises. We will survey two such regularization methods in the TLS setting. One is the iterative truncated TLS (TTLS) method which can solve a convergent sequence of projected linear systems generated by Lanczos bidiagonalization. The other one is to convert the Tikhonov… More >

Zhendong Luo¹, Fei Teng²

CMES-Computer Modeling in Engineering & Sciences, Vol.101, No.1, pp. 33-58, 2014, DOI:10.3970/cmes.2014.101.033

Abstract A semi-discrete Crank-Nicolson (CN) formulation about time and a fully discrete stabilized CN finite volume element (SCNFVE) formulation based on two local Gauss integrals and parameter-free with the second-order time accuracy are established for the non-stationary Navier-Stokes equations. The error estimates of the semi-discrete and fully discrete SCNFVE solutions are derived. Some numerical experiments are presented to illustrate that the fully discrete SCNFVE formulation possesses more advantages than its stabilized finite volume element formulation with the first-order time accuracy, thus validating that the fully discrete SCNFVE formulation is feasible and efficient for finding the numerical More >

Zhen Wang¹, Jonny Rutqvist², Ying Dai¹

CMES-Computer Modeling in Engineering & Sciences, Vol.92, No.6, pp. 539-556, 2013, DOI:10.3970/cmes.2013.092.539

Abstract Fractures in a discrete fracture network can be divided into two parts: Active fractures, which form a connected fracture network and dominate fluid flow and solute transport; and inactive fractures, which are dead-end parts of the fractures (isolated fractures will be incorporated into rock matrix) and do not contribute significantly to the fluid flow, but maybe important for the solute transport, especially for rock matrix diffusion. We present a multi-continuum method (including active fracture continuum, inactive fracture continuum and matrix continuum), which is based on the “multiple interacting continua” method, to describe fluid flow and… More >

Mikael A. Langthjem¹, Masami Nakano²

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.4, pp. 227-241, 2013, DOI:10.3970/cmes.2013.096.227

Abstract This paper is concerned with a mathematical model of a simple axisymmetric silencer-like model, consisting of a hole-tone feedback system equipped with a tailpipe. The unstable shear layer is modeled via a discrete vortex method, based on axisymmetric vortex rings. The aeroacoustic model is based on the Powell- Howe theory of vortex sound. Boundary integrals are discretized via the boundary element method; but the tailpipe is represented by the exact (one-dimensional) solution. It is demonstrated though numerical examples that this numerical model can display lock-in of the self-sustained flow oscillations to the resonant acoustic oscillations. More >

Martino Pani¹, Fulvia Taddei¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.4, pp. 279-300, 2013, DOI:10.3970/cmes.2013.094.279

Abstract The Cell Method (CM) is a numerical method to solve field equations starting from its direct algebraic formulation. For two-dimensional problems it has been demonstrated that using simplicial elements with an affine interpolation, the CM obtains the same fundamental equation of the Finite Element Method (FEM); using the quadratic interpolation functions, the fundamental equation differs depending on how the dual cell is defined. In spite of that, the CM can still provide the same convergence rate obtainable with the FEM. Particularly, adopting a uniform triangulation and basing the dual cells on the Gauss points of More >