Browsing Computational Mathematics (CM) by Title
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Analysis of extreme wave events on the southern coast of Brazil
(Natural Hazards and Earth System Sciences, 20141231)Using the wave model SWAN (simulating waves nearshore), high waves on the southwestern Atlantic generated by extratropical cyclones are simulated from 2000 to 2010, and their impact on the Rio Grande do Sul (RS) coast is ... 
Apparent slip mechanism between two spheres based on solvent rheology: Theory and implication for the shear thinning of nonBrownian suspensions
(Physical Review Fluids, 20181210)Analytical results for the apparent slip between two spheres in a simple biviscous model of a shear thinning fluid are presented. Velocity profiles and apparent slip lengths along the surfaces are analyzed in order to ... 
Arithmetic method of doubleinjectionelectrode model for resistivity measurement through metal casing
(IEEE Transactions on Geoscience and Remote Sensing, 20101231)Throughcasing resistivity (TCR) measurement instruments such as Cased Hole Formation Resistivity are extensively used for the dynamic monitoring of oil reservoirs during the production phase in oil wells to evaluate the ... 
Asymptotic Models for the Electric Potential across a Highly Conductive Casing
(Computers and Mathematics with Applications, 201807)We analyze a configuration that involves a steelcased borehole, where the casing that covers the borehole is considered as a highly conductive thin layer. We develop an asymptotic method for deriving reduced problems ... 
Automatic fitting of conical envelopes to freeform surfaces for flank CNC machining
(Computer Aided Design, 201710)We propose a new algorithm to detect patches of freeform surfaces that can be well approximated by envelopes of a rotational cone under a rigid body motion. These conical envelopes are a preferable choice from the ... 
Automatic RedChannel underwater image restoration
(Journal of Visual Communication and Image Representation, 20151231)Underwater images typically exhibit color distortion and low contrast as a result of the exponential decay that light suffers as it travels. Moreover, colors associated to different wavelengths have different attenuation ... 
BBIPED: BCAMBaltogar Industrial Platform for Engineering Design
(18th International Conference on Circuits, Systems, Communications and Computers (CSCC 2014); Advances in Engineering Mechancis and Materials, Proc.the International Conference; on Industrial Engineering (INDE 2014)", 20141231)Currently, commercial software for computational fluid dynamics offers a good set of features to deal with traditional designs. Within a competitive market industrial innovation is a key factor that must be faced by ... 
A C 0 interior penalty discontinuous Galerkin Method for fourthorder total variation flow. II: Existence and uniqueness
(NMPDE:Numerical Methods For Partial Differential Equations, 20190225)We prove the existence and uniqueness of a solution of a C0 Interior Penalty Discontinuous Galerkin (C0 IPDG) method for the numerical solution of a fourth‐order total variation flow problem that has been developed in part ... 
A C0 interior penalty discontinuous Galerkin method for fourth‐order total variation flow I: Derivation of the method and numerical results
(NMPDE:Numerical Methods For Partial Differential Equations, 20190223)We consider the numerical solution of a fourth‐order total variation flow problem representing surface relaxation below the roughening temperature. Based on a regularization and scaling of the nonlinear fourth‐order parabolic ... 
Computation of slat noise sources using adaptive FEM and lighthill's analogy
(19th AIAA/CEAS Aeroacoustics Conference, 20131231)This is a summary of preliminary results from simulations with the 30P30N highlift device. We used the General Galerkin finite element method (G2), where no explicit subgrid model is used, and where the computational mesh ... 
Computational cost estimates for parallel shared memory isogeometric multifrontal solvers
(Computers and Mathematics with Applications, 20141231)In this paper we present computational cost estimates for parallel shared memory isogeometric multifrontal solvers. The estimates show that the ideal isogeometric shared memory parallel direct solver scales as $\mathcal{O}( ... 
Computational cost of isogeometric multifrontal solvers on parallel distributed memory machines
(Computer Methods in Applied Mechanics and Engineering, 20151231)This paper derives theoretical estimates of the computational cost for isogeometric multifrontal direct solver executed on parallel distributed memory machines. We show theoretically that for the $C^{p1}$ global continuity ... 
Computational fixedpoint theory for differential delay equations with multiple time lags
(Journal of Differential Equations, 20121231)We introduce a general computational fixedpoint method to prove existence of periodic solutions of differential delay equations with multiple time lags. The idea of such a method is to compute numerical approximations of ... 
Dimensionally adaptive hpfinite element simulation and inversion of 2D magnetotelluric measurements
(Journal of Computational Science, 20160901)Magnetotelluric (MT) problems often contain different subdomains where the conductivity of the media depends upon one, two, or three spatial variables. Traditionally, when a MT problem incorporates a threedimensional (3D) ... 
Direct FEM large scale computation of turbulent multiphase flow in urban water systems and marine energy
(Proceesings of ECCOMAS Congress 2016 VII European Congress on Computational Methods in Applied Sciences and Engineering, 20161130)HighReynolds number turbulent incompressible multiphase flow represents a large class of engineering problems of key relevance to society. Here we describe our work on modeling two such problems: 1. The Consorcio de Aguas ... 
Direct finite element simulation of turbulent flow for marine based renewable energy
(Companion paper to F. Wendt, et. al. International energy agency ocean energy systems task 10 wave energy converter modeling verification and validation. In 12th European Wave and Tidal Energy Conference, 2017., 2017)In this article we present a computational framework for simulation of turbulent flow in marine based renewable energy applications. In particular, we focus on floating structures and rotating turbines. This work is an ... 
Direct solvers performance on hadapted grids
(Computers and Mathematics with Applications, 20151231)We analyse the performance of direct solvers when applied to a system of linear equations arising from an $h$adapted, $C^0$ finite element space. Theoretical estimates are derived for typical $h$refinement patterns arising ... 
Discontinuous highorder finitevolume/finiteelement method for inviscid compressible flows
(53rd AIAA Aerospace Sciences Meeting (2015), 20151231)The discontinuous, hybrid controlvolume/finiteelement method merges the desirable conservative properties and intuitive physical formulation of the finitevolume technique, with the capability of local arbitrary highorder ... 
Discrete maximum principles for nonlinear parabolic PDE systems
(IMA Journal of Numerical Analysis, 20121231)Discrete maximum principles (DMPs) are established for finite element approximations of systems of nonlinear parabolic partial differential equations with mixed boundary and interface conditions. The results are based on ... 
Discrete nonnegativity for nonlinear cooperative parabolic PDE systems with nonmonotone coupling
(Mathematics and Computers in Simulation, 20131231)Discrete nonnegativity principles are established for finite element approximations of nonlinear parabolic PDE systems with mixed boundary conditions. Previous results of the authors are extended such that diagonal dominance ...