Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Probability distribution of a passive scalar: A soluble example (1990)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 2 (1990), S. 1303-1305 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The probability distribution, in space, of a passive scalar advected by a model, divergence-free, velocity field is analytically calculated. It is found to have a logarithmic singularity at the origin and a quasi-Gaussian decay away from it. The significance of this result for the general case of convection of passive scalars and the relation to a recent theory of Yakhot and Sinai [Phys. Rev. Lett. 63, 1962 (1989)] are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.857578
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Low-reynolds number approximation for turbulent eddy viscosity (1994)
    Springer
    Journal of scientific computing 9 (1994), S. 283-292 
    Details
    ISSN: 1573-7691
    Keywords: Eddy viscosity ; renormalization group ; backward facing step
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We develop a model for turbulent eddy viscosity as a solution of a quartic equation. The model is consistent with the renormalization group (RNG)-based low-Reynolds number approximation for turbulent viscosity. The model has been tested for flow over a backward facing step and the predicted results show very good agreement with the experimental data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01575033
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Attenuating Artificial Dissipation in the Computation of Navier–Stokes Turbulent Boundary Layers (1998)
    Springer
    Journal of scientific computing 13 (1998), S. 151-172 
    Details
    ISSN: 1573-7691
    Keywords: Artificial dissipation ; fourth-difference coefficient ; airfoil flows
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We propose a new formulation of the fourth-difference artificial dissipation coefficient needed for the Navier–Stokes solutions. This coefficient is scaled by a damping function which is expressed in terms of the Baldwin–Lomax algebraic turbulence model. The suggested scaling function damps the artificial dissipation across the boundary layer. The objective of this paper is to test the ability of the suggested damped scaling coefficient to provide (a) a given accuracy on a coarser grid; and (b) an accurate computing of turbulent boundary layers. To accomplish this, attached and separated transonic flows over the NACA 0012 airfoil, and turbulent flow over a flat plate have been considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1023270026913
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Renormalization group formulation of large-eddy simulations (1989)
    Springer
    Journal of scientific computing 4 (1989), S. 139-158 
    Details
    ISSN: 1573-7691
    Keywords: Renormalization group ; turbulence ; large-eddy simulation ; subgridscale viscosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Conclusions In this work we hae shown that the subgrid model following from the renormalization group theory of turbulence is capable of describing turbulent channel flow. Although the resolution of all simulations was relatively modest (16×64×64), the results revealed an excellent agreement between theory and physical experiment in the range of variation ofR * from 125 to 400. The model seems to give a faithful description of turbulence in the wall region including correct, approximately Reynolds-number independent value of the spacing between the streaks. More experiments are needed to investigate the quality of the model for higher Reynolds number flows and to determine the resolution requirements of this LES model as the Reynolds number increases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01061499
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    An algebraic-Q 4 turbulence model for attached and separated airfoil flows (1996)
    Springer
    Journal of scientific computing 11 (1996), S. 71-98 
    Details
    ISSN: 1573-7691
    Keywords: Eddy viscosity ; renormalization group ; airfoil flows
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract An algebraic eddy viscosity model, based on a new length scale has been developed. The model proposes the eddy viscosity as a solution of a quartic (Q 4) equation. The turbulent length scale for attached and separated flows is defined by employing a vorticity functionF =yΩD introduced in the Baldwin-Lomax model. The algebraic-Q 4 eddy viscosity model was incorporated into Navier-Stokes code and tested for complex transonic airfoil flows with separation. The results are compared with the experimental data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02088818
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    HIGH-ORDER-ACCURATE DISCRETIZATION STENCIL FOR AN ELLIPTIC EQUATION (1996)
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 23 (1996), S. 367-377 
    Details
    ISSN: 0271-2091
    Keywords: discretization ; high-order accuracy ; duct flow ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The coefficients for a nine-point high-order-accurate discretization scheme for an elliptic equation ∇2u- γ2u=r0 (∇2 is the two-dimensional Laplacian operator) are derived. Examples with Dirichlet and Neumann boundary condtions are considered. In order to demonstrate the high-order accuracy of the method, numerical results are compared with exact solutions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 7
    Electronic Resource
    Electronic Resource
    Computing flux intensity factors by a boundary method for elliptic equations with singularities (1998)
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 14 (1998), S. 657-670 
    Details
    ISSN: 1069-8299
    Keywords: flux intensity factors ; singularities ; multiple singular points ; eliptic PDEs ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A simple method for computing the flux intensity factors associated with the asymptotic solution of elliptic equations having a large convergence radius in the vicinity of singular points is presented. The Poisson and Laplace equations over domains containing boundary singularities due to abrupt change of the boundary geometry or boundary conditions are considered. The method is based on approximating the solution by the leading terms of the local symptotic expansion, weakly enforcing boundary conditions by minimization of a norm on the domain boundary in a least-squares sense. The method is applied to the Motz problem, resulting in extremely accurate estimates for the flux intensity factors. It is shown that the method converges exponentially with the number of singular functions and requires a low computational cost. Numerical results to a number of problems concerned with the Poisson equation over an L-shaped domain, and over domains containing multiple singular points, demonstrate accurate estimates for the flux intensity factors. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 8
    Electronic Resource
    Electronic Resource
    A highly accurate numerical solution of a biharmonic equation (1997)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Methods for Partial Differential Equations 13 (1997), S. 375-391 
    Details
    ISSN: 0749-159X
    Keywords: Biharmonic equation ; finite difference ; high-order accuracy ; Mathematics and Statistics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: The coefficients for a nine-point high-order accuracy discretization scheme for a biharmonic equation ∇ 4u = f(x, y) (∇2 is the two-dimensional Laplacian operator) are derived. The biharmonic problem is defined on a rectangular domain with two types of boundary conditions: (1) u and ∂2u/∂n2 or (2) u and ∂u/part;n (where ∂/part;n is the normal to the boundary derivative) are specified at the boundary. For both considered cases, the truncation error for the suggested scheme is of the sixth-order O(h6) on a square mesh (hx = hy = h) and of the fourth-order O(h4xh2xh2y h4y) on an unequally spaced mesh. The biharmonic equation describes the deflection of loaded plates. The advantage of the suggested scheme is demonstrated for solving problems of the deflection of rectangular plates for cases of different boundary conditions: (1) a simply supported plate and (2) a plate with built-in edges. In order to demonstrate the high-order accuracy of the method, the numerical results are compared with exact solutions. © John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 13: 375-391, 1997
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 9
    Electronic Resource
    Electronic Resource
    An accurate semi-analytic finite difference scheme for two-dimensional elliptic problems with singularities (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Numerical Methods for Partial Differential Equations 14 (1998), S. 281-296 
    Details
    ISSN: 0749-159X
    Keywords: singularities ; elliptic PDE ; Laplace equation ; high-order Finite Difference Schemes ; Mathematics and Statistics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics
    Notes: A high-order semi-analytic finite difference scheme is presented to overcome degradation of numerical performance when applied to two-dimensional elliptic problems containing singular points. The scheme, called Least-Square Singular Finite Difference Scheme (L-S SFDS), applies an explicit functional representation of the exact solution in the vicinity of the singularities, and a conventional finite difference scheme on the remaining domain. It is shown that the L-S SFDS is “pollution” free, i.e., no degradation in the convergence rate occurs because of the singularities, and the coefficients of the asymptotic solution in the vicinity of the singularities are computed as a by-product with a very high accuracy. Numerical examples for the Laplace and Poisson equations over domains containing re-entrant corners or abrupt changes in the boundary conditions are presented. © 1998 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 14: 281-296, 1998
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...