Search results for "numerical"

Modeling mass transfer in fracture flows with the time domain-random walk method

2019

The time domain-random walk method was developed further for simulating mass transfer in fracture flows together with matrix diffusion in surrounding porous media. Specifically, a time domain-random walk scheme was developed for numerically approximating solutions of the advection-diffusion equation when the diffusion coefficient exhibits significant spatial variation or even discontinuities. The proposed scheme relies on second-order accurate, central-difference approximations of the advective and diffusive fluxes. The scheme was verified by comparing simulated results against analytical solutions in flow configurations involving a rectangular channel connected on one side with a porous ma…

Varieties of algebras with pseudoinvolution and polynomial growth

2017

Let A be an associative algebra with pseudoinvolution (Formula presented.) over an algebraically closed field of characteristic zero and let (Formula presented.) be its sequence of (Formula presented.) -codimensions. We shall prove that such a sequence is polynomially bounded if and only if the variety generated by A does not contain five explicitly described algebras with pseudoinvolution. As a consequence, we shall classify the varieties of algebras with pseudoinvolution of almost polynomial growth, i.e. varieties of exponential growth such that any proper subvariety has polynomial growth and, along the way, we shall give also the classification of their subvarieties. Finally, we shall de…

2016

The Global Burden of Disease, Injuries, and Risk Factor study 2013 (GBD 2013) is the first of a series of annual updates of the GBD. Risk factor quantification, particularly of modifiable risk factors, can help to identify emerging threats to population health and opportunities for prevention. The GBD 2013 provides a timely opportunity to update the comparative risk assessment with new data for exposure, relative risks, and evidence on the appropriate counterfactual risk distribution. Attributable deaths, years of life lost, years lived with disability, and disability-adjusted life-years (DALYs) have been estimated for 79 risks or clusters of risks using the GBD 2010 methods. Risk-outcome p…

Numerical simulation of experiments in a meandering flume

2001

Numerical modelling of the flow in a meandering channel is compared with experiments done by one of the authors. A peculiar 2DH model, where bottom shear stresses are computed taking into account also accelerations, has been developed for the comparison. Good results are obtained in some sections of the channel, but, in others, some experimentally observed flow features are not well reproduced. An explanation is offered for the difficulties encountered in modelling the strong secondary current that appears along the bend.

STEP 3: Restart Target DB2

2011

Finally, we RESTART TARGET DB2 and it's stopped databases.

The role of the tidal and wind forces on the hydrodynamic flow pattern in the Augusta Harbour (Italy)

2012

On the Computational Error in 3D Simulation of Cutting

2009

EXTERNAL RECIRCULATION IN PRS TYPE TURBINE: EXPERIMENTAL AND NUMERICAL RESULTS.

2022

Cavitation is a relevant phenomenon for structural safety and noise level in hydraulic turbines, occurring when water pressure falls below the vapor value at a given temperature. In this case bubbles of vapor grow inside the liquid and move along with it. When the pressure returns above the vapor value the bubble collapses, and the pressure can locally achieve very high values, up to 7000 bars (Kumar & Saini, 2010). Moreover, if the bubble was confined also by the solid wall of a blade, the solid particles suspended in the fluid can be transported by the fluid ones and hit the solid wall at very high velocity, generating erosion. Cavitation is also the source of high frequency noise, ve…

Better numerical approximation by Durrmeyer type operators

2018

The main object of this paper is to construct new Durrmeyer type operators which have better features than the classical one. Some results concerning the rate of convergence and asymptotic formulas of the new operator are given. Finally, the theoretical results are analyzed by numerical examples.

Estimates for the differences of positive linear operators and their derivatives

2019

The present paper deals with the estimate of the differences of certain positive linear operators and their derivatives. Oxur approach involves operators defined on bounded intervals, as Bernstein operators, Kantorovich operators, genuine Bernstein-Durrmeyer operators, and Durrmeyer operators with Jacobi weights. The estimates in quantitative form are given in terms of the first modulus of continuity. In order to analyze the theoretical results in the last section, we consider some numerical examples.