pinecone/core-2020-05-10-deduplication huggingface dataset:
Antioxidant activity of six Portuguese thyme species essential oils

The essential oils of Thymus caespititius, T. camphoratus, T. capitellatus, T. carnosus, T. pulegioides, T. zygis subsp.
zygis and T. zygis subsp. sylvestris collected in diff erent regions of Portugal, including the Azores islands, were evaluated for
preventing lipid peroxidation and scavenging free radicals, and hydroxyl and superoxide anions. T. zygis subsp. zygis oil possessed
the best capacity for preventing lipid peroxidation (IC50 = 0.030 ± 0.003 mg/ml), immediately followed by the oils isolated
from T. zygis subsp. sylvestris collected in diff erent regions of Portugal. IC50 values ranged from 0.066 ± 0.003 to 0.087 ±
0.001 mg/ml in oils isolated from samples from Alcanena and Duas Igrejas, respectively. The oils isolated from T. zygis subsp.
sylvestris, independent of the harvesting region, were shown to be the most eff ective for scavenging free radicals (0.358–
0.453 mg/ml). The best capacity for scavenging hydroxyl radicals was found in the oils of T. camphoratus collected in Espartal
and of T. caespititius of Lordelo, with IC50 < 0.5 mg/ml. The low oil amount did not allow IC50 values for the superoxide anion
scavenging determination, therefore considering a unique oil concentration (5 mg/ml), the highest inhibition percentages
(>50%) were registered with the essential oils of T. zygis subsp. sylvestris from Duas Igrejas and Covão do Coelho, and of T.
capitellatus from Sines. Copyright © 2010 John Wiley & Sons, Ltd
Volatile and sensory characterization of Xarel.lo white wines

et al.A comprehensive study based on the profiling and quantification of the volatile composition and the application of descriptive sensory analysis of 25 commercial monovarietal white wines (var. Xarel.lo) from different vintages and from representative wine cellars along the Penedés region (Catalonia, Spain) was performed in order to characterize representative wines that are being commercialized under the O.D. Penedés. In addition, relationships between the instrumental (volatile) and sensory variables were found through the application of partial least squares regression. The results showed great differences between younger wines and wines that underwent the crianza (or ageing) process. The first group of wines was characterized by a marked fruity and floral odour and fresh taste, while the second group was characterized by more complex sensory attributes such as toasted, spicy and compote odour attributes. These differences in sensory characteristics were related to a higher content of higher alcohol acetates and ethyl and methyl esters of fatty acids in wines included in the first group, while the second group was characterized by a lower concentration of esters, but higher concentration of compounds related to wine ageing, such as furfural, 5-methylfurfural and vitispiranes.The authors would like to thank  the PET2007-0134 and AGL2006-04514 and AGL2009-13361-CO2-01  projects for funding.Peer Reviewe
Fourth Order Compact Formulation of Navier-Stokes Equations and Driven
  Cavity Flow at High Reynolds Numbers

A new fourth order compact formulation for the steady 2-D incompressible
Navier-Stokes equations is presented. The formulation is in the same form of
the Navier-Stokes equations such that any numerical method that solve the
Navier-Stokes equations can also be applied to this fourth order compact
formulation. In particular in this work the formulation is solved with an
efficient numerical method that requires the solution of tridiagonal systems
using a fine grid mesh of 601x601. Using this formulation, the steady 2-D
incompressible flow in a driven cavity is solved up to Reynolds number of
20,000 with fourth order spatial accuracy. Detailed solutions are presented
Numerical boundary conditions for globally mass conservative methods to solve the shallow-water equations and applied to river flow

44 Pag., 18 Fig., 4 Tabl.\ud
\ud
The definitive version is available at:\ud
http://www3.interscience.wiley.com/A revision of some well-known discretization techniques for the numerical boundary conditions in 1D shallow-water flow models is presented. More recent options are also considered in the search for a fully conservative technique that is able to preserve the good properties of a conservative scheme used for the interior points. Two conservative numerical schemes are used as representatives of the families of explicit and implicit numerical methods. The implementation of the different boundary options to these schemes is compared by means of the simulation of several test cases with exact solution. The schemes with the global conservation boundary discretization are applied to the simulation of a real river flood wave leading to very satisfactory results.Peer reviewe
Three-dimensional numerical simulation of Marangoni instabilities in liquid bridges : influence of geometrical aspect ratio

Oscillatory Marangoni convection in silicone oil liquid bridges with different geometrical aspect ratios is investigated by three-dimensional and time-dependent numerical simulations, based on control volume methods in staggered cylindrical non uniform grids. The three-dimensional oscillatory flow regimes are studied and compared with previous experimental and theoretical results. The results show that the critical wave number (m), related to the azimuthal spatio-temporal flow structure, is a monotonically decreasing function of the geometrical aspect ratio of the liquid bridge (defined as ratio of the length to the diameter). For this function a general correlation formula is found, that is in agreement with the previous experimental findings. The critical Marangoni number and the oscillation frequency are decreasing functions of the aspect ratio; however, the critical Marangoni number, based on the axial length of the bridge, does not change much with the aspect ratio. For each aspect ratio investigated, the onset of the instability from the axi-symmetric steady state to the three-dimensional oscillatory one is characterized by the appearance of a standing wave regime that exhibits, after a certain time, a second transition to a travelling wave regime. The standing wave regime is more stable for lower aspect ratios since it lasts for a long time. This behaviour is explained on the basis of the propagation velocity of the disturbances in the liquid phase; for this velocity a general correlation law is found as function of the aspect ratio and of the Marangoni number
A high-order triangular discontinuous Galerkin oceanic shallow water model

The article of record as published may be located at http://dx.doi.org/10.1002/fld.1562A high-order triangular discontinuous Galerkin (DG) method is applied to the two-dimensional oceanic shallow water equations. The DG method can be characterized as the fusion of finite elements with finite volumes. This DG formulation uses high-order Lagrange polynomials on the triangle using nodal sets up to 15th order. Both the area and boundary integrals are evaluated using order 2N Gauss cubature rules. The use of exact integration for the area integrals leads naturally to a full mass matrix; however, by using straight-edged triangles we eliminate the mass matrix completely from the discrete equations. Besides obviating the need for a mass matrix, triangular elements offer other obvious advantages in the construction of oceanic shallow water models, specifically the ability to use unstructured grids in order to better represent the continental coastlines for use in tsunami modeling. In this paper, we focus primarily on testing the discrete spatial operators by using six test cases-three of which have analytic solutions. The three tests having analytic solutions show that the high-order triangular DG method exhibits exponential convergence. Furthermore, comparisons with a spectral element model show that the DG model is superior for all polynomial orders and test cases considered. Copyright (C) 2007 John Wiley & Sons, Ltd
Preserving bounded and conservative solutions of transport in 1D shallow-water flow with upwind numerical schemes: Application to fertigation and solute transport in rivers

The definitive version is available at:\ud
\ud
http://www3.interscience.wiley.com/journal/2861/homeThis work intends to show that conservative upwind schemes based on a separate discretization of the scalar solute transport from the shallow-water equations are unable to preserve uniform solute profiles in situations of one-dimensional unsteady subcritical flow. However, the coupled discretization of the system is proved to lead to the correct solution in first-order approximations. This work is also devoted to show that, when using a coupled discretization, a careful definition of the flux limiter function in second-order TVD schemes is required in order to preserve uniform solute profiles. The work shows that, in cases of subcritical irregular flow, the coupled discretization is necessary but nevertheless not sufficient to ensure concentration distributions free from oscillations and a method to avoid these oscillations is proposed. Examples of steady and unsteady flows in test cases, river and irrigation are presented.Peer reviewe
Goal-Oriented Mesh Adaptation using a Dissipation-Based Error Indicator

The accuracy of functionals of solutions of the Euler equations, solved using a finite volume code,\ud
are examined under grid refinement. It is shown that a commonly used adaptation indicator based\ud
on local solution gradients is ineffective in reducing functional error for flows with supersonic regions.\ud
A novel indicator is introduced which attempts to quantify that part of the error in the functional\ud
due to the explicitly added dissipation present in the numerical flux. The scheme is considerably\ud
simpler and computationally cheaper than other recently proposed a posteriori error estimators for\ud
finite volume schemes, but does not account for all sources of error. In mind of this, emphasis is placed\ud
on numerical evaluation of the performance of the scheme, and it is shown to be extremely effective in\ud
both estimating and reducing error for a wide range of flows
Conservative integrals of adiabatic Durran’s equations

Potential advances are investigated in the area of generalized anelastic approximations. Consistent control-volume integrals are designed and compared for the established Lipps-Hemler form (of anelastic approximation) and Durran's pseudo-incompressible form. The Durran system provides a unique theoretical tool - useful for research of geophysical and stellar flows - within the existing set of reduced, Boussinesq-type fluid models. It represents thermal aspects of compressibility free of sound waves, yet the momentum equation is unapproximated. The latter admits unabbreviated baroclinic production of vorticity, thus facilitating separation of compressibility and baroclinicity effects per se. Compared with other reduced fluid models, there is little cumulative experience with integrating the Durran system. Perhaps the first conservative integrations of Durran's equations are presented, using flux-form transport methods and exact projection for the associated elliptic problem. Because the resulting code is built from a preexisting anelastic model, the consistency of the numerics is assured thus minimizing uncertainties associated with ad hoc code comparisons. While broader physical implications are addressed, theoretical considerations are illustrated with examples of atmospheric flows
A Cartesian grid technique based on one-dimensional integrated radial basis function networks for natural convection in concentric annuli

This paper reports a radial-basis-function (RBF)-based Cartesian grid technique for the simulation of\ud
two-dimensional buoyancy-driven flow in concentric annuli. The continuity and momentum equations are represented in the\ud
equivalent stream function formulation that reduces the number of equations from three to one, but involves higher-order derivatives. The present technique uses a Cartesian grid to discretize the problem domain. Along a grid line, one-dimensional integrated RBF networks (1D-IRBFNs) are employed to represent the field variables. The capability of 1D-IRBFNs to handle unstructured points with accuracy is exploited to describe non-rectangular boundaries in a Cartesian grid, while the method's ability to avoid the reduction of convergence rate caused by differentiation is instrumental in improving the quality of the approximation of high-order derivatives. The method is applied to simulate thermally-driven flows in annuli between two circular cylinders and between an outer square cylinder and an inner circular cylinder. High Rayleigh-number solutions are achieved and they are in good agreement with previously published numerical data
NURBS-enhanced finite element method for Euler equations

This is the pre-peer reviewed version of the following article: Sevilla, R.; Fernandez, S.; Huerta, A. NURBS-enhanced finite element method for Euler equations. "International journal for numerical methods in fluids", Juliol 2008, vol. 57, núm. 9, p. 1051-1069., which has been published in final form at http://www3.interscience.wiley.com/journal/117905455/abstractIn this work, the NURBS-enhanced finite element method (NEFEM) is combined with a discontinuous Galerkin (DG) formulation for the numerical solution of Euler equations of gas dynamics. With NEFEM, numerical fluxes along curved boundaries are computed much more accurately due to the exact geometric representation of the computational domain. The proper implementation of the wall boundary condition and the exact geometry provide accurate results even with a linear approximation of the solution. A detailed comparison of NEFEM in front of isoparametric finite elements is presented, demonstrating the superiority of NEFEM approach for both linear and higher-order computations.Peer ReviewedPostprint (author’s final draft
Discontinuous Galerkin methods for the Stokes equations using divergence-free approximations

This is the pre-peer reviewed version of the following article: Montlaur, A.; Fernandez, S.; Huerta, A. Discontinuous Galerkin methods for the Stokes equations using divergence-free approximations. "International journal for numerical methods in fluids", Juliol 2008, vol. 57, núm. 9, p. 1071-1092., which has been published in final form at http://www3.interscience.wiley.com/journal/117953707/abstract?CRETRY=1&SRETRY=0A discontinuous Galerkin (DG) method with solenoidal approximation for the simulation of incompressible flow is proposed. It is applied to the solution of the Stokes equations. The interior penalty method is employed to construct the DG weak form. For every element, the approximation space for the velocity field is decomposed as the direct sum of a solenoidal space and an irrotational space. This allows to split the DG weak form into two uncoupled problems: the first one solves for the velocity and the hybrid pressure (pressure along the mesh edges) and the second one allows the computation of the pressure in the element interior. Furthermore, the introduction of an extra penalty term leads to an alternative DG formulation for the computation of solenoidal velocities with no presence of pressure terms. Pressure can then be computed as a post-process of the velocity solution. Numerical examples demonstrate the applicability of the proposed methodologies.Peer ReviewedPostprint (author’s final draft
Friction term discretization and limitation to preserve stability and conservation in the 1D shallow-water model: Application to unsteady irrigation and river flow

The original version is available at:\ud
\ud
http://www3.interscience.wiley.com/journal/2861/homeFriction is one of the relevant forces included in the momentum equation of the 1D shallow-water model. This work shows that a pointwise discretization of the friction term unbalances this term with the rest of the terms in the equation in steady state. On the other hand, an upwind discretization of the friction term ensures the correct discrete balance. Furthermore, a conservative technique based on the limitation of the friction value is proposed in order to avoid unbounded values of the friction term in unsteady cases of advancing front over dry and rough surfaces. This limitation improves the quality of unsteady solutions in wet/dry fronts and guarantees the numerical stability in cases with dominant friction terms. The proposed discretization is validated in some test cases with analytical solution or with measured data and used in some practical cases.Peer reviewe
Two-level finite element method with a stabilizing subgrid for the incompressible Navier-Stokes equations

We consider the Galerkin finite element method for the incompressible Navier-Stokes equations in two dimensions. The domain is discretized into a set of regular triangular elements and the finite-dimensional spaces employed consist of piecewise continuous linear interpolants enriched with the residual-free bubble functions. To find the bubble part of the solution, a two-level finite element method with a stabilizing subgrid of a single node is described, and its application to the Navier-Stokes equation is displayed. Numerical approximations employing the proposed algorithm are presented for three benchmark problems. The results show that the proper choice of the subgrid node is crucial in obtaining stable and accurate numerical approximations consistent with the physical configuration of the problem at a cheap computational cost. Copyright © 2008 John Wiley & Sons, Ltd
Discussions on Driven Cavity Flow

The widely studied benchmark problem, 2-D driven cavity flow problem is
discussed in details in terms of physical and mathematical and also numerical
aspects. A very brief literature survey on studies on the driven cavity flow is
given. Based on the several numerical and experimental studies, the fact of the
matter is, above moderate Reynolds numbers physically the flow in a driven
cavity is not two-dimensional. However there exist numerical solutions for 2-D
driven cavity flow at high Reynolds numbers
A finite point method for adaptive-three-dimensional compressible flow calculations

Electronic version of an article published as "International journal for numerical methods in fluids", vol. 60, no 9, 2009, p. 937-971. DOI:10.1002/fld.1892  <http://onlinelibrary.wiley.com/doi/10.1002/fld.1892/abstract>The finite point method (FPM) is a meshless technique, which is based on both, a weighted least-squares numerical approximation on local clouds of points and a collocation technique which allows obtaining the discrete system of equations. The research work we present is part of a broader investigation into the capabilities of the FPM to deal with 3D applications concerning real compressible fluid flow problems. In the first part of this work, the upwind-biased scheme employed for solving the flow equations is described. Secondly, with the aim of exploiting the meshless capabilities, an h-adaptive methodology for 2D and 3D compressible flow calculations is developed. This adaptive technique applies a solution-based indicator in order to identify local clouds where new points should be inserted in or existing points could be safely removed from the computational domain. The flow solver and the adaptive procedure have been evaluated and the results are encouraging. Several numerical examples are provided in order to illustrate the good performance of the numerical methods presented.Peer ReviewedPostprint (author’s final draft
Efficient and Robust Algorithms for Solution of the Adjoint Compressible Navier–Stokes Equations with Applications

The complete discrete adjoint equations for an unstructured finite volume compressible Navier–Stokes\ud
solver are discussed with respect to the memory and time efficient evaluation of their residuals, and their\ud
solution. It is seen that application of existing iteration methods for the non-linear equation—suitably\ud
adjointed—has a property of guaranteed convergence provided that the non-linear iteration is well behaved.\ud
For situations where this is not the case, in particular for strongly separated flows, a stabilization technique\ud
based on the Recursive Projection Method is developed. This method additionally provides the dominant\ud
eigenmodes of the problem, allowing identification of flow regions that are unstable under the basic\ud
iteration. These are found to be regions of separated flow. Finally, an adjoint-based optimization with\ud
96 design variables is performed on a wing–body configuration. The initial flow has large regions of\ud
separation, which are significantly diminished in the optimized configuration
Bounds on outputs of the exact weak solution of the three-dimensional Stokes problem

A method for obtaining rigorous upper and lower bounds on an output of the exact weak solution of the three-dimensional Stokes problem is described. Recently bounds for the exact outputs of interest have been obtained for both the Poisson equation and the advection-diffusion-reaction equation. In this work, we extend this approach to the Stokes problem where a novel formulation of the method also leads to a simpler flux calculation based on the directly equilibrated flux method. To illustrate this technique, bounds on the flowrate are calculated for an incompressible creeping flow driven by a pressure gradient in an endless square channel with an array of rectangular obstacles in the center
Two-level finite element method with a stabilizing subgrid for the incompressible MHD equations

We consider the Galerkin finite element method (FEM) for the incompressible magnetohydrodynamic (MHD) equations in two dimension. The domain is discretized into a set of regular triangular elements and the finite-dimensional spaces employed consist of piecewise continuous linear interpolants enriched with the residual-free bubble functions. To find the bubble part of the solution, a two-level FEM with a stabilizing subgrid of a single node is described and its application to the MHD equations is displayed. Numerical approximations employing the proposed algorithm are presented for three benchmark problems including the MHD cavity flow and the MHD flow over a step. The results show that the proper choice of the subgrid node is crucial to get stable and accurate numerical approximations consistent with the physical configuration of the problem at a cheap computational cost. Furthermore, the approximate solutions obtained show the well-known characteristics of the MHD flow. Copyright © 2009 John Wiley & Sons, Ltd.The Scientific and Technical Research Council of Turkey (Contract 105T091
Simulation of incompressible viscous flows around moving objects by a variant of immersed boundary-Lattice Boltzmann method

A variant of immersed boundary-lattice Boltzmann method (IB-LBM) is presented in this paper to simulate incompressible viscous flows around moving objects. As compared with the conventional IB-LBM where the force density is computed explicitly by Hook's law or the direct forcing method and the non-slip condition is only approximately satisfied, in the present work, the force density term is considered as the velocity correction which is determined by enforcing the non-slip condition at the boundary. The lift and drag forces on the moving object can be easily calculated via the velocity correction on the boundary points. The capability of the present method for moving objects is well demonstrated through its application to simulate flows around a moving circular cylinder, a rotationally oscillating cylinder, and an elliptic flapping wing. Furthermore, the simulation of flows around a flapping flexible airfoil is carried out to exhibit the ability of the present method for implementing the elastic boundary condition. It was found that under certain conditions, the flapping flexible airfoil can generate larger propulsive force than the flapping rigid airfoil