Browsing Artikler, rapporter og annet (datateknologi og beregningsorienterte ingeniørfag) by Issue Date
Now showing items 120 of 161

Reiterated homogenization of nonlinear monotone operators in a general deterministic setting
(Journal article; Peer reviewed; Tidsskriftartikkel, 2009)We study reiterated homogenization of a nonlinear nonperiodic elliptic differential operator in a general deterministic setting as opposed to the usual stochastic setting. Our approach proceeds from an appropriate notion of convergence termed reiterated Σconvergence. A general deterministic homogenization theorem is proved and several concrete examples are studied under various structure hypotheses ... 
Fluidstructure Interaction for Water Hammers Effects in Petroleum and Nuclear Plants
(Journal article; Tidsskriftartikkel; Peer reviewed, 20111231)FluidStructure Interaction (FSI) becomes more and more the focus of computational engineering in Petroleum and Nuclear Industry in the last years. These problems are computer time consuming and require new stable and accurate coupling algorithms to be solved. For the last decades, the new development of coupling algorithms, and the increasing of computer performance have allowed to solve some ... 
Exact Asymptotic Expansion of Singular Solutions for the (2+1)D Protter Problem
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012) 
Steklov Problems in Perforated Domains with a Coefficient of Indefinite Sign
(Journal article; Peer reviewed; Tidsskriftartikkel, 2012) 
On heat conduction in domains containing noncoaxial cylinders
(Journal article; Peer reviewed; Tidsskriftartikkel, 2012)We consider heat conduction in domains containing noncoaxial cylinders. In particular, we present some regularity results for the solution and consider criteria which ensure the single valueness of the corresponding complex potential. Examples are discussed. In addition, we present some classes of cases where the parameters describing the solution are rational. Alternative ways of calculating the ... 
Quantitative analysis of accuracy of voidage computations in CFDDEM Simulations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012) 
Weighted Hardy Operators in Complementary Morrey Spaces
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012) 
Generalized Chessboard Structures Whose Effective Conductivities Are Integer Valued
(Journal article; Tidsskriftartikkel; Peer reviewed, 20120306)We consider generalized chessboard structures where the local conductivity takes two values 𝑎 and 𝑏 . All integer combinations of 𝑎 and 𝑏 which make the components of effective conductivity matrix integer valued are found. Moreover, we discuss the problem of estimating the effective conductivity matrix by using the finiteelement method. 
Homogenization of a singular random onedimensional PDE with timevarying coefficients
(Journal article; Tidsskriftartikkel; Peer reviewed, 20120504)In this paper we study the homogenization of a nonautonomous parabolic equation with a large random rapidly oscillating potential in the case of onedimensional spatial variable. We show that if the potential is a statistically homogeneous rapidly oscillating function of both temporal and spatial variables, then, under proper mixing assumptions, the limit equation is deterministic, and convergence ... 
On a New Class of Hardytype Inequalities
(Journal article; Tidsskriftartikkel; Peer reviewed, 20121105)In this paper, we generalize a Hardytype inequality to the class of arbitrary nonnegative functions bounded from below and above with a convex function multiplied with positive real constants. This enables us to obtain new generalizations of the classical integral Hardy, HardyHilbert, HardyLittlewoodPólya, and PólyaKnopp inequalities as well as of Godunova’s and of some recently obtained ... 
Weighted Hardy Operators in Complementary Morrey Spaces
(Journal article; Tidsskriftartikkel; Peer reviewed, 20121111)We study the weighted boundedness of the multidimensional weighted Hardytype operators and with radial type weight , in the generalized complementary Morrey spaces defined by an almost increasing function . We prove a theorem which provides conditions, in terms of some integral inequalities imposed on and , for such a boundedness. These conditions are sufficient in the general case, but we ... 
Some New Iterated HardyType Inequalities
(Journal article; Tidsskriftartikkel; Peer reviewed, 20121210) 
Weighted HardyType Inequalities in Variable Exponent MorreyType Spaces
(Journal article; Peer reviewed; Tidsskriftartikkel, 2013)We study the p(.) > q(.) boundedness of weighted multidimensional Hardytype operators Hw(alpha(.)) and Hw(alpha(.)) of variable order alpha(x), with radial weight w(vertical bar x vertical bar), from a variable exponent locally generalized Morrey space Lp(.),Lphi(.)(Rn, w) to another Lq(.),Lpsi(.)(Rn, w). The exponents are assumed to satisfy the decay condition at the origin and infinity. ... 
Deployment of a NeoHookean membrane: experimental and numerical analysis
(Journal article; Tidsskriftartikkel; Peer reviewed, 20130331)The aim of this research is to assess the response of a thin membrane subjected to highpressure gas loading for inflation. This procedure is applied during the design process of the membrane structure to allow the product to resist highpressure loading and to further characterize the hyperelastic material. The simulation in this work considers the standard procedures used in the LSDYNA software, ... 
Some new iterated Hardytype inequalities: the case theta=1
(Journal article; Tidsskriftartikkel; Peer reviewed, 20131108)In this paper we characterize the validity of the Hardytype inequality ∥ ∥ ∫ <sub>s</sub>∞) h(z)dz ∥ p,u,(0,t) ∥ q,w,(=,∞≤ c∥h∥ 1,v(0,∞) where 0 < p < ∞,0< q ≤ +∞, u, w and v are weight functions on (0,∞). It is pointed out that this characterization can be used to obtain new characterizations for the boundedness between weighted Lebesgue spaces ... 
Local refinement of ERBS curves
(Journal article; Peer reviewed; Chapter, 20131231)Exporational Bsplines (ERBS) provide a blending type construction where local functions at each knot are blended together by infinitely smooth basis functions. In this work we consider some specific ERBS curves that are approximations of parametric curves. We study local refinement to increase flexibility by inserting local control curves at points of interest on the ERBS curve. Inserting knots ... 
Design of water shock tube for testing shell materials
(Journal article; Tidsskriftartikkel; Peer reviewed, 20140415)This paper presents design considerations for a shock tube experimental rig used to investigate the dynamic failure mechanisms of shell geometries subjected to water shock impact loading. In such setup, it is desirable that the drive pressure used within the tube can provide a wide range of impulsive loads on the test structures and some flexibility can be achieved on the applied pulse durations. ... 
Numerical investigation of vibration and dynamic pressure of a vertical axis wind turbine
(Journal article; Tidsskriftartikkel; Peer reviewed, 20141231)In the environmental field, the problems of vibration reduction have become a major preoccupation, particularly on the noise generated by the acoustic radiation pressure produced by wind turbines. This paper is aimed at presenting the investigation on the application of FEM element method for study the acoustic radiation pressure produced by verticalaxis wind turbine. For this initiative, we ... 
Matrix factorization of multivariate Bernstein polynomials
(Journal article; Peer reviewed; Tidsskriftartikkel, 2015)Ordinary univariate Bernstein polynomials can be represented in matrix form using factor matrices. In this paper we present the deﬁnition and basic properties of such factor matrices extended from the univariate case to the general case of arbitrary number of variables by using barycentric coordinates in the hypersimplices of respective dimension. The main results in the paper are related to the ... 
Shock Tube. Detail overview of equipment and instruments in the shock tube experimental setup
(Book; Bok, 2015)The shock tube is a device in which a normal shock wave is produced by the interaction of fluids at significantly highpressure difference. The shock tube is comprised of two sections known as driver and driven sections. These two sections are interacted with the highspeed valve or a bursting disc. When the interaction happens, a shock wave forms almost instantaneously and propagates into the driven ...