Time Constant#

Time Constant = CONSTANT <float> [t]

Description / Usage#

This card is used to specify the model for the time constant parameter of the CARREAU, BINGHAM, CARREAU_WLF and CARREAU_SUSPENSION fluid options of the Liquid Constitutive Equation card. Definitions of the input parameters are as follows:

CONSTANT

Name of the model for the time constant.

  • <float> - the value of the time constant, λ.

LEVEL_SET

Name of the model for level-set dependent time constant. Allows for this time constant level to be a function of the level-set field. Specifically used for changing the time constant from one constant value on the negative side of the interface to another constant value on the positive side. The model requires three floats:

  • <float1> - the value of time constant in the negative regions of the level set function.

  • <float2> - the value of time constant in the positive regioons of the level-set function.

  • <float3> Length scale over which the transition occurs. If this parameter is set to zero, it will default to one-half the Level-Set Length Scale value specified.

Examples#

The following is a sample card that sets the time constant to 0.2.

Time Constant = CONSTANT 0.2

Technical Discussion#

See Description/Usage for Liquid Constitutive Equation card.