Yield Exponent

Yield Exponent = CONSTANT <float> [t]

Description / Usage

This card is used to specify the model for the yield exponent parameter, F, for the BINGHAM model option of the Liquid Constitutive Equation card, or when the Polymer Constitutive Equation card is SARAMITO_OLDROYDB, SARAMITO_GIESEKUS, or SARAMITO_PTT. Definitions of the input parameters are as follows:

CONSTANT <float>

Name of the model for the yield exponent. <float> the value of the yield exponent, F, which has the dimensions of inverse shear-rate in whatever units are consistent with the problem of interest and which connotes the steepness of the transition from solid to fluid behavior for the Bingham-Carreau-Yasuda model or the Saramito yield stress model.

For the BINGHAM model, if F is large, the material has an abrupt transition from solid-like to fluid-like behavior, whereas for a small F, the transition is more gradual.

For the SARAMITO_OLDROYDB, SARAMITO_GIESEKUS, and SARAMITO_PTT models, the material has and abrupt transition when F equals zero. This Transistion becomes smooth for nonzero when F is greater than zero, with the transition becoming more gradual as F increases.

Examples

The following is a sample card that sets the yield exponent to 10.0

Yield Exponent = CONSTANT 10.0.

Technical Discussion

See Description/Usage for Liquid Constitutive Equation and Polymer Constitutive Equation cards.