atmTurbulentHeatFluxTemperature

Table of Contents

Properties

  • The atmTurbulentHeatFluxTemperature boundary condition provides a fixed heat constraint on temperature, i.e. T, to specify temperature gradient through an input heat source which can either be specified as absolute power [W], or as flux [W/m2].
  • The atmTurbulentHeatFluxTemperature condition inherits the traits of the fixedGradient boundary condition.

Required fields: 

nut    | Turbulent viscosity              [m2/s]
k      | Turbulent kinetic energy         [m2/s2]

Model equations

The boundary condition expression when the heat-source type is absolute power (heatSource=power):

\[ \grad{T} = \frac{q}{A_p C_{p_0} \alpha_p + \zeta} \]

The boundary condition expression when the heat-source type is flux (heatSource=flux):

\[ \grad{T} = \frac{q}{C_{p_0} \alpha_p + \zeta} \]

where

\( T \) = Temperature [K]
\( q \) = Heat source value [W (power) or W/m2 (flux)]
\( A_p \) = Patch surface-normal area [m2]
\( C_{p_0} \) = Specific heat capacity [m2/s2/K]
\( \alpha_p \) = Effective thermal diffusivity [kg/m/s]
\( \zeta \) = Small value to prevent floating point exceptions [-]

Usage

Example of the boundary condition specification: 

<patchName>
{
    // Mandatory entries (unmodifiable)
    type            atmTurbulentHeatFluxTemperature;
    heatSource      flux;
    alphaEff        alphaEff;

    // Mandatory entries (runtime modifiable)
    Cp0             0.001;
    q               uniform 10;

    // Optional (inherited) entries
    value           uniform 0;
    gradient        uniform 0;
}

where the entries mean:

Property Description Type Required Default
type Type name: atmTurbulentHeatFluxTemperature word yes -
heatSource Heat source type word yes -
alphaEff Name of turbulent thermal diff. field [kg/m/s] word yes -
Cp0 Specific heat capacity TimeFunction1<scalar> yes -
q Heat source value PatchFunction1<scalar> yes -

The inherited entries are elaborated in:

Options for the heatSource entry: 

power  | Absolute power heat source [W]
flux   | Flux heat source [W/m^2]

Further information

Tutorial:

Source code

History

  • Introduced in version v2006