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DUNE for Multi-{Phase, Component, Scale, Physics, ...} flow and transport in porous media
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freeflow/rans/twoeq/lowrekepsilon/model.hh File Reference

A single-phase, isothermal low-Reynolds k-epsilon model. More...

#include <dumux/common/properties.hh>
#include <dumux/freeflow/properties.hh>
#include <dumux/freeflow/rans/model.hh>
#include <dumux/freeflow/rans/twoeq/indices.hh>
#include <dumux/freeflow/turbulencemodel.hh>
#include "problem.hh"
#include "fluxvariables.hh"
#include "localresidual.hh"
#include "volumevariables.hh"
#include "iofields.hh"

Go to the source code of this file.

Description

A single-phase, isothermal low-Reynolds k-epsilon model.

Single-phase Reynolds-Averaged Navier-Stokes flow For a detailed model decription see freeflow/rans/model.hh.

The low-Reynolds k-epsilon models calculate the eddy viscosity with two additional PDEs, one for the turbulent kinetic energy (k) and for the dissipation ( \( \varepsilon \)). The model uses the one proposed by Chien [12]. A good overview and additional models are given in Patel et al. [48].

The turbulent kinetic energy balance is identical with the one from the k-epsilon model, but the dissipation includes a dampening function ( \( D_\varepsilon \)): \( \varepsilon = \tilde{\varepsilon} + D_\varepsilon \):

\[ \frac{\partial \left( k \right)}{\partial t} + \nabla \cdot \left( \textbf{v} k \right) - \nabla \cdot \left( \left( \nu + \frac{\nu_\text{t}}{\sigma_\text{k}} \right) \nabla k \right) - 2 \nu_\text{t} \textbf{S} \cdot \textbf{S} + \tilde{\varepsilon} + D_\varepsilon = 0 \]

.

The dissipation balance is changed by introducing additional functions ( \( E_\text{k}\), \( f_1 \), and \( f_2 \)) to account for a dampening towards the wall:

\[ \frac{\partial \left( \tilde{\varepsilon} \right)}{\partial t} + \nabla \cdot \left( \textbf{v} \tilde{\varepsilon} \right) - \nabla \cdot \left( \left( \nu + \frac{\nu_\text{t}}{\sigma_{\varepsilon}} \right) \nabla \tilde{\varepsilon} \right) - C_{1\tilde{\varepsilon}} f_1 \frac{\tilde{\varepsilon}}{k} 2 \nu_\text{t} \textbf{S} \cdot \textbf{S} + C_{2\tilde{\varepsilon}} f_2 \frac{\tilde{\varepsilon}^2}{k} - E_\text{k} = 0 \]

.

The kinematic eddy viscosity \( \nu_\text{t} \) is dampened by \( f_\mu \):

\[ \nu_\text{t} = C_\mu f_\mu \frac{k^2}{\tilde{\varepsilon}} \]

.

The auxiliary and dampening functions are defined as:

\[ D_\varepsilon = 2 \nu \nicefrac{k}{y^2} \]

\[ E_\text{k} = -2 \nu \frac{\tilde{\varepsilon}}{y^2} \exp \left( -0.5 y^+ \right) \]

\[ f_1 = 1 \]

\[ f_2 = 1 - 0.22 \exp \left( - \left( \frac{\mathit{Re}_\text{t}}{6} \right)^2 \right) \]

\[ f_\mu = 1 - \exp \left( -0.0115 y^+ \right) \]

\[ \mathit{Re}_\text{t} = \frac{k^2}{\nu \tilde{\varepsilon}} \]

.

Finally, the model is closed with the following constants:

\[ \sigma_\text{k} = 1.00 \]

\[ \sigma_\varepsilon =1.30 \]

\[ C_{1\tilde{\varepsilon}} = 1.35 \]

\[ C_{2\tilde{\varepsilon}} = 1.80 \]

\[ C_\mu = 0.09 \]

Classes

struct  Dumux::Properties::LowReKEpsilonModelTraits< dimension >
 Traits for the low-Reynolds k-epsilon model. More...
 
struct  Dumux::Properties::TTag::LowReKEpsilon
 The type tag for the single-phase, isothermal low-Reynolds k-epsilon model. More...
 
struct  Dumux::Properties::ModelTraits< TypeTag, TTag::LowReKEpsilon >
 < states some specifics of the isothermal low-Reynolds k-epsilon model More...
 
struct  Dumux::Properties::FluxVariables< TypeTag, TTag::LowReKEpsilon >
 The flux variables. More...
 
struct  Dumux::Properties::LocalResidual< TypeTag, TTag::LowReKEpsilon >
 The local residual. More...
 
struct  Dumux::Properties::VolumeVariables< TypeTag, TTag::LowReKEpsilon >
 Set the volume variables property. More...
 
struct  Dumux::Properties::IOFields< TypeTag, TTag::LowReKEpsilon >
 The specific I/O fields. More...
 
struct  Dumux::Properties::TTag::LowReKEpsilonNI
 The type tag for the single-phase, non-isothermal low-Reynolds k-epsilon model. More...
 
struct  Dumux::Properties::ModelTraits< TypeTag, TTag::LowReKEpsilonNI >
 The model traits of the non-isothermal model. More...
 
struct  Dumux::Properties::VolumeVariables< TypeTag, TTag::LowReKEpsilonNI >
 Set the volume variables property. More...
 
struct  Dumux::Properties::IOFields< TypeTag, TTag::LowReKEpsilonNI >
 The specific non-isothermal I/O fields. More...
 

Namespaces

namespace  Dumux
 
namespace  Dumux::Properties
 
namespace  Dumux::Properties::TTag
 Type tag for numeric models.
 
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