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Arthur G. Kravchenko

Other affiliations: Center for Turbulence Research
Bio: Arthur G. Kravchenko is an academic researcher from Stanford University. The author has contributed to research in topics: Reynolds number & Turbulence. The author has an hindex of 6, co-authored 7 publications receiving 1636 citations. Previous affiliations of Arthur G. Kravchenko include Center for Turbulence Research.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a high-order accurate numerical method based on B-splines and compared with previous upwindbiased and central finite-difference simulations and with the existing experimental data is presented.
Abstract: Flow over a circular cylinder at Reynolds number 3900 is studied numerically using the technique of large eddy simulation. The computations are carried out with a high-order accurate numerical method based on B-splines and compared with previous upwind-biased and central finite-difference simulations and with the existing experimental data. In the very near wake, all three simulations are in agreement with each other. Farther downstream, the results of the B-spline computations are in better agreement with the hot-wire experiment of Ong and Wallace [Exp. Fluids 20, 441–453 (1996)] than those obtained in the finite-difference simulations. In particular, the power spectra of velocity fluctuations are in excellent agreement with the experimental data. The impact of numerical resolution on the shear layer transition is investigated.

641 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that discrepancies between the results of dealiased spectral and standard nondialiased finite-difference methods are due to both aliasing and truncation errors with the latter being the leading source of differences.
Abstract: Aliased and dealiased numerical simulations of a turbulent channel flow are performed using spectral and finite difference methods. Analytical and numerical studies show that aliasing errors are more destructive for spectral and high-order finite-difference calculations than for low-order finite-difference simulations. Numerical errors have different effects for different forms of the nonlinear terms in the Navier?Stokes equations. For divergence and convective forms, spectral methods are energy-conserving only if dealiasing is performed. For skew-symmetric and rotational forms, both spectral and finite-difference methods are energy-conserving even in the presence of aliasing errors. It is shown that discrepancies between the results of dealiased spectral and standard nondialiased finite-difference methods are due to both aliasing and truncation errors with the latter being the leading source of differences. The relative importance of aliasing and truncation errors as compared to subgrid scale model terms in large eddy simulations is analyzed and discussed. For low-order finite-difference simulations, truncation errors can exceed the magnitude of the subgrid scale term.

564 citations

Journal ArticleDOI
TL;DR: A B-spline based numerical method on a zonal embedded grid aimed at reducing the computational requirements for large eddy simulations (LES) and direct numerical simulations (DNS) of wall-bounded turbulent flows.
Abstract: A B-spline based numerical method on a zonal embedded grid has been developed. The method is aimed at reducing the computational requirements for large eddy simulations (LES) and direct numerical simulations (DNS) of wall-bounded turbulent flows. The objective is to reduce the number of grid points required to resolve the near-wall eddies without placing a large number of grid points in the outer layers. DNS and LES calculations of a turbulent channel flow were performed on a grid with a zone near the wall that was refined in all three directions. The results from the zonal grid calculations show good agreement with previously published numerical and experimental results obtained for the same flow conditions. The zonal grid calculations required only a fraction of the CPU time required for the single zone grid calculation with the same near-wall grid density. In addition, the memory requirements for the zonal grid calculations are significantly reduced.

196 citations

Journal ArticleDOI
TL;DR: In this paper, the relation between skin-friction on the wall and streamwise vortices observed near the wall was examined using data from direct numerical simulations of fully developed turbulent channel flow.
Abstract: Databases from direct numerical simulations of fully developed turbulent channel flow were used to examine the relation between skin‐friction on the wall and streamwise vortices observed near the wall. It is shown that the wall shear rate correlates with streamwise vortices near the wall and that the maximum correlation occurs downstream and with lateral displacement from the location of skin‐friction measurement. Conditionally‐averaged statistics taken near high skin‐friction regions indicate that the higher skin‐friction values are associated with streamwise vortices located closer to the wall. Visual studies of the time evolution of near‐wall streamwise vortices and skin‐friction on the wall also indicate that the high skin‐friction footprints on the wall can be attributed to streamwise vortices.

194 citations

Journal ArticleDOI
TL;DR: In this paper, a numerical technique for computations of turbulent flows is described, which is based on B-spline and allows grid embedding in physically significant flow regions, and the results indicate that the method is accurate and efficient.
Abstract: A numerical technique for computations of turbulent flows is described. The technique is based on B-splines and allows grid embedding in physically significant flow regions. Numerical tests, which include solutions of nonlinear advection-diffusion equations and computations of flow over a circular cylinder at Reynolds numbers up to 300, indicate that the method is accurate and efficient. In computations of flow over a cylinder, the lift, drag, and base suction coefficients agree well with existing experimental data and previous numerical simulations.

126 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the concept of isogeometric analysis is proposed and the basis functions generated from NURBS (Non-Uniform Rational B-Splines) are employed to construct an exact geometric model.
Abstract: The concept of isogeometric analysis is proposed. Basis functions generated from NURBS (Non-Uniform Rational B-Splines) are employed to construct an exact geometric model. For purposes of analysis, the basis is refined and/or its order elevated without changing the geometry or its parameterization. Analogues of finite element h - and p -refinement schemes are presented and a new, more efficient, higher-order concept, k -refinement, is introduced. Refinements are easily implemented and exact geometry is maintained at all levels without the necessity of subsequent communication with a CAD (Computer Aided Design) description. In the context of structural mechanics, it is established that the basis functions are complete with respect to affine transformations, meaning that all rigid body motions and constant strain states are exactly represented. Standard patch tests are likewise satisfied. Numerical examples exhibit optimal rates of convergence for linear elasticity problems and convergence to thin elastic shell solutions. A k -refinement strategy is shown to converge toward monotone solutions for advection–diffusion processes with sharp internal and boundary layers, a very surprising result. It is argued that isogeometric analysis is a viable alternative to standard, polynomial-based, finite element analysis and possesses several advantages.

5,137 citations

Journal ArticleDOI
TL;DR: In this paper, a second-order accurate, highly efficient method is developed for simulating unsteady three-dimensional incompressible flows in complex geometries, which is achieved by using boundary body forces that allow the imposition of the boundary conditions on a given surface not coinciding with the computational grid.
Abstract: A second-order accurate, highly efficient method is developed for simulating unsteady three-dimensional incompressible flows in complex geometries. This is achieved by using boundary body forces that allow the imposition of the boundary conditions on a given surface not coinciding with the computational grid. The governing equations, therefore, can be discretized and solved on a regular mesh thus retaining the advantages and the efficiency of the standard solution procedures. Two different forcings are tested showing that while the quality of the results is essentially the same in both cases, the efficiency of the calculation strongly depends on the particular expression. A major issue is the interpolation of the forcing over the grid that determines the accuracy of the scheme; this ranges from zeroth-order for the most commonly used interpolations up to second-order for an ad hoc velocity interpolation. The present scheme has been used to simulate several flows whose results have been validated by experiments and other results available in the literature. Finally in the last example we show the flow inside an IC piston/cylinder assembly at high Reynolds number; to our knowledge this is the first example in which the immersed boundary technique is applied to a full three-dimensional complex flow with moving boundaries and with a Reynolds number high enough to require a subgrid-scale turbulence model.

1,643 citations

Journal ArticleDOI
TL;DR: In this article, direct numerical simulation (DNS) of turbulent flows has been reviewed and the complementary nature of experiments and computations in turbulence research has been illustrated, as well as how DNS has impacted turbulence modeling and provided further insight into the structure of turbulent boundary layers.
Abstract: ▪ Abstract We review the direct numerical simulation (DNS) of turbulent flows. We stress that DNS is a research tool, and not a brute-force solution to the Navier-Stokes equations for engineering problems. The wide range of scales in turbulent flows requires that care be taken in their numerical solution. We discuss related numerical issues such as boundary conditions and spatial and temporal discretization. Significant insight into turbulence physics has been gained from DNS of certain idealized flows that cannot be easily attained in the laboratory. We discuss some examples. Further, we illustrate the complementary nature of experiments and computations in turbulence research. Examples are provided where DNS data has been used to evaluate measurement accuracy. Finally, we consider how DNS has impacted turbulence modeling and provided further insight into the structure of turbulent boundary layers.

1,572 citations

Journal ArticleDOI
TL;DR: In this article, a review of scale-invariance properties of high-Reynolds-number turbulence in the inertial range is presented, focusing on dynamic and similarity subgrid models and evaluating how well these models reproduce the true impact of the small scales on large scale physics and how they perform in numerical simulations.
Abstract: ▪ Abstract Relationships between small and large scales of motion in turbulent flows are of much interest in large-eddy simulation of turbulence, in which small scales are not explicitly resolved and must be modeled. This paper reviews models that are based on scale-invariance properties of high-Reynolds-number turbulence in the inertial range. The review starts with the Smagorinsky model, but the focus is on dynamic and similarity subgrid models and on evaluating how well these models reproduce the true impact of the small scales on large-scale physics and how they perform in numerical simulations. Various criteria to evaluate the model performance are discussed, including the so-called a posteriori and a priori studies based on direct numerical simulation and experimental data. Issues are addressed mainly in the context of canonical, incompressible flows, but extensions to scalar-transport, compressible, and reacting flows are also mentioned. Other recent modeling approaches are briefly introduced.

1,395 citations

Book
01 Jan 2015
TL;DR: This updated edition includes new worked programming examples, expanded coverage and recent literature regarding incompressible flows, the Discontinuous Galerkin Method, the Lattice Boltzmann Method, higher-order spatial schemes, implicit Runge-Kutta methods and code parallelization.
Abstract: Computational Fluid Dynamics: Principles and Applications, Third Edition presents students, engineers, and scientists with all they need to gain a solid understanding of the numerical methods and principles underlying modern computation techniques in fluid dynamics By providing complete coverage of the essential knowledge required in order to write codes or understand commercial codes, the book gives the reader an overview of fundamentals and solution strategies in the early chapters before moving on to cover the details of different solution techniques This updated edition includes new worked programming examples, expanded coverage and recent literature regarding incompressible flows, the Discontinuous Galerkin Method, the Lattice Boltzmann Method, higher-order spatial schemes, implicit Runge-Kutta methods and parallelization An accompanying companion website contains the sources of 1-D and 2-D Euler and Navier-Stokes flow solvers (structured and unstructured) and grid generators, along with tools for Von Neumann stability analysis of 1-D model equations and examples of various parallelization techniques Will provide you with the knowledge required to develop and understand modern flow simulation codes Features new worked programming examples and expanded coverage of incompressible flows, implicit Runge-Kutta methods and code parallelization, among other topics Includes accompanying companion website that contains the sources of 1-D and 2-D flow solvers as well as grid generators and examples of parallelization techniques

1,228 citations