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Tytuł:
Foundations of the Navier-Stokes boundary conditions in fluid mechanics
Autorzy:
Badur, J.
Karcz, M.
Lemański, M.
Nastałek, L.
Powiązania:
https://bibliotekanauki.pl/articles/175407.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
enhancement
slip
Navier number
Navier-Stokes
nanoflow
Opis:
Until recently it was believed that Navier’s boundary condition could be given as a rigorous foundation for slip phenomena. Due to the latest measurements in the mass flow rate of a gas flowing through nano- and microchannels, several discrepancies in the mathematical modelling have been found. Thus, in the literature, the opinion persists for the Navier slip condition to be correct only under certain circumstances, particularly those restricted to the first order boundary conditions. One of many ways to eliminate this discrepancy, which is extensively employed in the contemporary literature, is to develop a variety of the so-called second order boundary conditions. This path, however, seems incorrect since it lacks consistency between the bulk stress tensor and its boundary representation. In the paper we propose to replace the classical Navier slip condition with the new, more general Navier-Stokes slip boundary condition. Instead of the usual method of consideration, the boundary condition is presented as following from the mass and momentum balances within a thin, shell-like moving layer. Owing to this, the problem of consistency between the internal and external friction in a viscous fluid is solved within the framework of new layer balances, and a proper form of constitutive relations for friction and mobility forces. Finally, the common features of the Navier, Stokes, Maxwell and Reynolds concepts of a boundary slip layer are compared and revalorized. The classifications of different mobility mechanisms, important for flows in nano-, microchannels are also discussed.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2011, 123; 3-55
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shape derivatives for general objective functions and the incompressible Navier-Stokes equations
Autorzy:
Schmidt, S.
Schulz, V.
Powiązania:
https://bibliotekanauki.pl/articles/969869.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
shape optimization
shape derivative
Navier-Stokes
adjoint calculus
Opis:
The aim of this paper is to present the shape derivative for a wide array of objective functions using the incompressible Navier-Stokes equations as a state constraint. Most real world applications of computational fluid dynamics are shape optimization problems in nature, yet special shape optimization techniques are seldom used outside the field of elliptic partial differential equations and linear elasticity. This article tries to be self contained, also presenting many useful results from the literature. We conclude with a comparison of different objective functions for the shape optimization of an obstacle in a channel, which can be done quite conveniently when one knows the general form of the shape gradient.
Źródło:
Control and Cybernetics; 2010, 39, 3; 677-713
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A parallel adaptive code for compressible Navier-Stokes simulations
Autorzy:
Banaś, K.
Powiązania:
https://bibliotekanauki.pl/articles/1954541.pdf
Data publikacji:
1999
Wydawca:
Politechnika Gdańska
Tematy:
numerical simulations
compressible flow
Navier-Stokes solver
finite element method
parallel computing
adaptive meshes
Opis:
The paper presents a finite element code for compressible flow simulations. The code has two important features: adaptivity to increase accuracy of computations by selectively refining a finite element mesh and efficient parallel performance due to a special implementation based on concept of patches of elements. The algorithm for approximating the compressible Navier-Stokes equations is a version of the stabilized finite element method. Three time integration strategies are implemented, explicit, linear implicit and nonlinear implicit, and the GMRES method is used to solve systems of linear equations. For parallel simulations the code uses a special algorithm for mesh partition. The performance of the code is tested for two examples of supersonic flows: one inviscid and one viscous.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 1999, 3, 1; 17-37
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On a Navier-Stokes type equation and inequality
Autorzy:
Prouse, Giovanni
Powiązania:
https://bibliotekanauki.pl/articles/1361107.pdf
Data publikacji:
1992
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Opis:
A Navier-Stokes type equation corresponding to a non-linear relationship between the stress tensor and the velocity deformation tensor is studied and existence and uniqueness theorems for the solution, in the 3-dimensional case, of the Cauchy-Dirichlet problem, for a bounded solution and for an almost periodic solution are given. An inequality which in some sense is the limit of the equation is also considered and existence theorems for the solution of the Cauchy-Dirichlet problems and for a periodic solution are stated.
Źródło:
Banach Center Publications; 1992, 27, 2; 367-371
0137-6934
Pojawia się w:
Banach Center Publications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Regularity and stability of optimal controls of nonstationary Navier-Stokes equations
Autorzy:
Wachsmuth, D.
Powiązania:
https://bibliotekanauki.pl/articles/970093.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
sterowanie optymalne
równanie Naviera-Stokesa
stabilność Lipschitza
optimal control
Navier-Stokes equations
control constraints
Lipschitz stability
Opis:
The regularity and stability of optimal controls of nonstationary Navier-Stokes equations are investigated. Under suitable assumptions every control satisfying first-order necessary conditions is shown to be a continuous function in both space and time. Moreover, the behaviour of a locally optimal control under certain perturbations of the cost functional and the state equation is investigated. Lipschitz stability is proven provided a second-order sufficient optimality condition holds.
Źródło:
Control and Cybernetics; 2005, 34, 2; 387-409
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rationality of solving 3D circulation problems exclusively with the use of the Navier-Stokes equation (Reynolds equation)
Autorzy:
Koronowicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/1986684.pdf
Data publikacji:
2002
Wydawca:
Politechnika Gdańska
Tematy:
3D circulation problems
vortex theory
Navier-Stokes equation
Opis:
The paper presents problems connected with solving 3D circulation problems. The existence of vortex singularities in the flow behind a body is a characteristic feature of such problems. The vortices influence the velocity and pressure fields in the vicinity of a body. A proposition of rational merging the methods based on the N-S equation together with vortex methods (based on the vorticity equation) is discussed. Such a connection enables accurate and efficient determination of vortex singularities in the flow behind a body.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 1; 217-224
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some stability results for reactive Navier-Stokes-Poisson systems
Autorzy:
Ducomet, B.
Powiązania:
https://bibliotekanauki.pl/articles/1207638.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Opis:
We review the main results concerning the global existence and the stability of solutions for some models of viscous compressible self-gravitating fluids used in classical astrophysics.
Źródło:
Banach Center Publications; 2000, 52, 1; 83-118
0137-6934
Pojawia się w:
Banach Center Publications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multiblock parallel computation of an incompressible 3D flow in turbomachines
Autorzy:
Papierski, A.
Rabiega, M.
Powiązania:
https://bibliotekanauki.pl/articles/1954540.pdf
Data publikacji:
1999
Wydawca:
Politechnika Gdańska
Tematy:
numerical simulations
turbomachinery
incompressible flow
3D Navier-Stockes solver
Navier-Stokes solver
parallel computing
Opis:
A finite volume numerical method for the prediction of a fluid flow in complex geometries such as turbomachinery channels has been parallelized using a domain decomposition approach. A mathematical formulation of a 3-D incompressible steady flow has been presented on the basis of the N-S equations in a grid-oriented co-ordinate system with contravariant velocity components. A parallelized pressure-based implicit algorithm with discretization on a staggered grid has been developed. A message exchange system with a boundary exchange, developed by the authors, has been described. Exemplary calculations have been carried out for a laminar flow through a curved duct and for an inviscid flow through a stage of the centrifugal pump. A good agreement has been obtained in both the cases. Despite considerable simplification that has been introduced in the flow through the pump stage, the computations have shown nearly the same pressure rise in the stage as the measurements. Further directions of numerical investigations of a flow through turbomachines, including in particular those devoted to pressure losses related to the rotor-stator interaction, have been mentioned.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 1999, 3, 1; 39-52
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A non-element method of solving the two-dimensional Navier-Lamé equation in problems with non-homogeneous polygonal subregions
Autorzy:
Zieniuk, E.
Bołtuć, A.
Powiązania:
https://bibliotekanauki.pl/articles/1933185.pdf
Data publikacji:
2008
Wydawca:
Politechnika Gdańska
Tematy:
Navier-Lamé equation
boundary problems
subregions
PIES
Opis:
The paper introduces a parametric integral equation system (PIES) for solving 2D boundary problems defined on connected polygonal domains described by the Navier-Lame equation. Parametric linear functions were applied in the PIES to define analytically the polygonal subregions' interfaces. Only corner points and additional extreme points on the interface between the connected subregions are posed to practically define a polygonal domain. An important advantage of this approach is that the number of such points is independent of the area of identically shaped domains due to the elimination of traditional elements from modeling, the number of those elements being dependent on the domain's surface area. In order to test the reliability and effectiveness of the proposed method, test examples are included in which areas of displacements and stresses are analyzed in each subregion.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2008, 12, 1-2; 71-84
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the numerical solution of one inverse problem for a linearized two-dimensional system of Navier-Stokes equations
Autorzy:
Jenaliyev, Muvasharkhan
Ramazanov, Murat
Yergaliyev, Madi
Powiązania:
https://bibliotekanauki.pl/articles/2216154.pdf
Data publikacji:
2022
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Navier-Stokes equations
inverse problem
numerical solution
Opis:
The paper studies the numerical solution of the inverse problem for a linearized two-dimensional system of Navier-Stokes equations in a circular cylinder with a final overdetermination condition. For a biharmonic operator in a circle, a generalized spectral problem has been posed. For the latter, a system of eigenfunctions and eigenvalues is constructed, which is used in the work for the numerical solution of the inverse problem in a circular cylinder with specific numerical data. Graphs illustrating the results of calculations are presented.
Źródło:
Opuscula Mathematica; 2022, 42, 5; 709-725
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method of lines for the incompressible Navier-Stokes equations in the stream-function formulation
Autorzy:
Kosma, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1965151.pdf
Data publikacji:
2005
Wydawca:
Politechnika Gdańska
Tematy:
Navier-Stokes equation
stream-function formulation
method of lines
compact schemes
driven cavity
backward-facing step flow
Opis:
The aim of this paper is to simulate the laminar motion of viscous incompressible fluid and the transition between the laminar and the turbulent state in simply connected domains. The developed numerical algorithms are based on the solution of an initial-boundary value problem for the full incompressible Navier-Stokes equations, written in the form of a fourth-order equation for the stream function. The spatial derivatives and the boundary conditions are discretized on uniform grids by means of sixth-order compact schemes together with fourth-order finite-difference formulas, while the continuity of the time variable is preserved. The resulting system of ordinary differential equations has been integrated using the backward-differentiation predictor-corrector method. The efficiency of the numerical algorithms is demonstrated by solving two problems of viscous liquid plane flows in a square driven cavity and a backward-facing step. Calculations for the cavity flow configuration have been obtained for Reynolds numbers ranging from Re=100 to Re=30000 on uniform 50×50 and 100×100 grids. Calculations for the backward-facing step have been made for Re ≤ 3000 with channel lengths, L, within the range 10-30, on 30L×30 uniform grids. The computed stream-function contours and velocity fields have been compared with numerical results reported in the literature.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2005, 9, 1; 17-35
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Operator-splitting and Lagrange multiplier domain decomposition methods for numerical simulation of two coupled Navier-Stokes fluids
Autorzy:
Bresch, D.
Koko, J.
Powiązania:
https://bibliotekanauki.pl/articles/908383.pdf
Data publikacji:
2006
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
dwoistość
gradient sprzężony
przepływ Naviera-Stokesa
domain decomposition
duality
conjugate gradient
Navier-Stokes flows
Opis:
We present a numerical simulation of two coupled Navier-Stokes flows, using operator-splitting and optimization-based nonoverlapping domain decomposition methods. The model problem consists of two Navier-Stokes fluids coupled, through a common interface, by a nonlinear transmission condition. Numerical experiments are carried out with two coupled fluids; one with an initial linear profile and the other in rest. As expected, the transmission condition generates a recirculation within the fluid in rest.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2006, 16, 4; 419-429
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some application of the implicit function theorem to the stationary Navier-Stokes equations
Autorzy:
Holly, Konstanty
Powiązania:
https://bibliotekanauki.pl/articles/1313290.pdf
Data publikacji:
1991
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Opis:
We prove that - in the case of typical external forces - the set of stationary solutions of the Navier-Stokes equations is the limit of the (full) sequence of sets of solutions of the appropriate Galerkin equations, in the sense of the Hausdorff metric (for every inner approximation of the space of velocities). Then the uniqueness of the N-S equations is equivalent to the uniqueness of almost every of these Galerkin equations.
Źródło:
Annales Polonici Mathematici; 1991, 54, 2; 93-109
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A CFD package for the 3D Navier-Stokes computation of unsteady flows in turbomachines
Autorzy:
Thermann, H.
Schmidt, S.
Weiss, C.
Niehuis, R.
Powiązania:
https://bibliotekanauki.pl/articles/1967647.pdf
Data publikacji:
2001
Wydawca:
Politechnika Gdańska
Tematy:
CFD
computational fluid dynamics CFD
turbomachinery
laminar-to-turbulent transition
flutter
clocking
Navier-Stokes package
Opis:
A 3D Navier-Stokes package for the time-accurate computation of unsteady flows in turbomachines with emphasis on wide applicability, portability and efficiency is presented. The package consists of three components: the elliptic grid generator FRAME, the parallelised implicit Reynolds- and Favre-averaged Navier-Stokes solver PANTA and the post-processor TREAT especially designed for unsteady flow phenomena. The applicability of the package covers both rotor/stator interaction and blade flutter phenomena in multirow and multipassage 2D, Quasi3D and general 3D configurations in a wide range of flow velocities (subsonic, transonic). For turbulent computations either a Low-Reynolds-Number k-" or k-! turbulence model is available. Additionally, an algebraic transition model can be chosen from a variety of different models to enhance the accuracy of prediction for transitional flow phenomena. A description of the underlying algorithms and numerical methods as well as the main features and characteristics of each of the three components is given. Furthermore, selected examples of typical turbomachinery applications are shown to demonstrate these features.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2001, 5, 4; 537-547
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Global existence for a one-dimensional model in gas dynamics
Autorzy:
Njamkepo, Serge
Powiązania:
https://bibliotekanauki.pl/articles/1339279.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
capillarity
Navier-Stokes equations
gas dynamics
Opis:
We prove the existence of a global solution for a one-dimensio- nal Navier-Stokes system for a gas with internal capillarity.
Źródło:
Applicationes Mathematicae; 1996-1997, 24, 2; 203-221
1233-7234
Pojawia się w:
Applicationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Survey of applications of discrete vortex method in civil engineering
Autorzy:
Nowicki, T.
Powiązania:
https://bibliotekanauki.pl/articles/390713.pdf
Data publikacji:
2009
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
discrete vortex method
Navier-Stokes equation
Opis:
This paper includes an introduction to Discrete Vortex Method (DVM) and its comparison with other methods of computer fluid dynamics. In its second part it focuses on the most important applications of DVM from the civil engineering point of view. Some examples known form literature are presented theoretical as well as experimental.
Źródło:
Budownictwo i Architektura; 2009, 5, 2; 29-38
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-dimensional vertical Reynolds-Averaged Navier-Stokes equations versus one-dimensional Saint-Venant model for rapidly varied open channel water flow modelling
Autorzy:
Szydłowski, M.
Zima, P.
Powiązania:
https://bibliotekanauki.pl/articles/241158.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
mathematical modelling
Reynolds-averaged Navier-Stokes equations
Saint-Venant equations
free surface flow
rapidly varied flow
dam-break problem
Opis:
The paper concerns mathematical modelling of free surface open channel water flow. In order to simulate the flow two models are used -- two-dimensional vertical Reynolds-Averaged Navier-Stokes equations and one-dimensional Saint-Venant equations. The former is solved with SIPMLE algorithm of finite difference method using Marker and Cell technique to trace a free surface movement. The latter is solved using the finite volume method. The dam-break (water column collapse) problem on horizontal bottom is investigated as a test case. The calculated results are compared with each other. The numerical simulations are examined against laboratory experiment presented by Koshizuka et al (1995). The possibility of using the described models to simulate rapidly varied flow is discussed.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2006, 53, 4; 295-309
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of a near wall model to Navier-Stokes equations with nonlinear time-relaxation model
Autorzy:
İhan, Özgül
Powiązania:
https://bibliotekanauki.pl/articles/2175530.pdf
Data publikacji:
2022
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
boundary layers
laminar
near wall models
NWM
Navier-Stokes equation with nonlinear time-relaxation model
NSE-NTR
warstwy graniczne
równanie Naviera-Stokesa z nieliniowym modelem relaksacji w czasie
Opis:
It is difficult and essential to determine appropriate boundary conditions for the flow averages because they depend on the behavior of the unknown flow near the wall. Large-eddy simulation (LES) is one of the promising approaches. LES estimates local spatial averages ū of the velocity u of the fluid. The main problem is modeling near-wall turbulence in complex geometries. Inspired by the works of Navier and Maxwell, the boundary conditions are developed on the wall. In this study, the appropriate friction coefficient for 2-D laminar flows is computed, and existing boundary layer theories are used to improve numerical boundary conditions for flow averages. The slip with friction and penetration with resistance boundary conditions are considered. Numerical tests on two-dimensional channel flow across a step using this boundary condition on the top and bottom wall and the step are performed.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2022, 21, 2; 39--50
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł

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