functionrayleigh

Rayleigh number with smooth transition to lower limit

Extends from Modelica.Icons.Function (Icon for functions).

Information

This function returns the Rayleigh number. The parameter RaMin is used to transition to a lower limit for the Rayleigh number. This is helpful to avoid a Rayleigh number of zero or to avoid an expression for a convection coefficient that has an infinite derivative near zero, i.e., if h=f(Ra(1/2)).

Inputs

TypeNameDefaultDescription
Modelica.Units.SI.LengthxLayer thickness
Modelica.Units.SI.DensityrhoMass density
Modelica.Units.SI.SpecificHeatCapacityc_pSpecific heat capacity
Modelica.Units.SI.DynamicViscositymuDynamic viscosity
Modelica.Units.SI.ThermalConductivitykThermal conductivity
Modelica.Units.SI.TemperatureT_aTemperature of surface a
Modelica.Units.SI.TemperatureT_bTemperature of surface b
RealRa_minMinimum value for Rayleigh number

Outputs

TypeNameDefaultDescription
RealRaRayleigh number

Revisions

  • May 21, 2015, by Michael Wetter:
    Reformulated to reduce use of the division macro in Dymola. This is for issue 417.
  • July 2, 2013, by Michael Wetter:
    Renamed function from raleigh to rayleigh.
  • August 18 2010, by Michael Wetter:
    First implementation.