scholarly journals Enhanced Physics-Based Numerical Schemes for Two Classes of Turbulence Models

2009 ◽  
Vol 2009 ◽  
pp. 1-13
Author(s):  
Leo G. Rebholz
Keyword(s):  
Finite Element ◽  
Differential Operator ◽  
Stokes Equations ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Numerical Schemes ◽  
Discrete Laplacian ◽  
Navier Stokes Equations ◽  
Approximate Deconvolution ◽  
Finite Element Schemes

We present enhanced physics-based finite element schemes for two families of turbulence models, the models and the Stolz-Adams approximate deconvolution models. These schemes are delicate extensions of a method created for the Navier-Stokes equations in Rebholz (2007), that achieve high physical fidelity by admitting balances of both energy and helicity that match the true physics. The schemes' development requires carefully chosen discrete curl, discrete Laplacian, and discrete filtering operators, in order to permit the necessary differential operator commutations.

Simulation of the Turbulent Flow Inside the Combustion Chamber of a Reciprocating Engine With a Finite Element Method

1994 ◽  
Vol 116 (2) ◽  
pp. 363-369 ◽  
Author(s):  
Y. Mao ◽  
M. Buffat ◽  
D. Jeandel
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Turbulent Flows ◽  
Stokes Equations ◽  
Numerical Procedure ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Numerical Precision ◽  
Element Method

This paper presents numerical simulations of turbulent flows during the intake and the compression strokes of a model engine. The Favre average Navier-Stokes equations are solved with a k-ε turbulence model. The numerical procedure uses a time dependent semi-implicit scheme and a finite element method with a moving mesh (Buffat, 1991, Mao, 1990). Results of 2-D axisymmetrical calculations with and without inlet swirl are presented and compared to experimental data (Lance et al., 1991). The influence of different turbulence models and the numerical precision of the simulations are also discussed.

A finite element method for the Navier-Stokes equations in moving domain with application to hemodynamics of the left ventricle

2017 ◽  
Vol 32 (4) ◽  
Author(s):  
Alexander Danilov ◽  
Alexander Lozovskiy ◽  
Maxim Olshanskii ◽  
Yuri Vassilevski
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Left Ventricle ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Time Step ◽  
Navier Stokes Equations ◽  
Computed Tomography Images ◽  
Time Dependent Domain ◽  
Element Method

AbstractThe paper introduces a finite element method for the Navier-Stokes equations of incompressible viscous fluid in a time-dependent domain. The method is based on a quasi-Lagrangian formulation of the problem and handling the geometry in a time-explicit way. We prove that numerical solution satisfies a discrete analogue of the fundamental energy estimate. This stability estimate does not require a CFL time-step restriction. The method is further applied to simulation of a flow in a model of the left ventricle of a human heart, where the ventricle wall dynamics is reconstructed from a sequence of contrast enhanced Computed Tomography images.

Parallel iterative finite-element algorithms for the Navier–Stokes equations with nonlinear slip boundary conditions

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Kangrui Zhou ◽  
Yueqiang Shang
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Parallel Algorithms ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Slip Boundary Conditions ◽  
Navier Stokes Equations ◽  
Slip Boundary ◽  
Parallel Iterative ◽  
Nonlinear Slip Boundary Conditions

AbstractBased on full domain partition, three parallel iterative finite-element algorithms are proposed and analyzed for the Navier–Stokes equations with nonlinear slip boundary conditions. Since the nonlinear slip boundary conditions include the subdifferential property, the variational formulation of these equations is variational inequalities of the second kind. In these parallel algorithms, each subproblem is defined on a global composite mesh that is fine with size h on its subdomain and coarse with size H (H ≫ h) far away from the subdomain, and then we can solve it in parallel with other subproblems by using an existing sequential solver without extensive recoding. All of the subproblems are nonlinear and are independently solved by three kinds of iterative methods. Compared with the corresponding serial iterative finite-element algorithms, the parallel algorithms proposed in this paper can yield an approximate solution with a comparable accuracy and a substantial decrease in computational time. Contributions of this paper are as follows: (1) new parallel algorithms based on full domain partition are proposed for the Navier–Stokes equations with nonlinear slip boundary conditions; (2) nonlinear iterative methods are studied in the parallel algorithms; (3) new theoretical results about the stability, convergence and error estimates of the developed algorithms are obtained; (4) some numerical results are given to illustrate the promise of the developed algorithms.

Sign in / Sign up

Export Citation Format

Share Document