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OpenFOAM-12/applications
Henry Weller 9105b80a55 momentumTransportModels::lambdaThixotropic: New momentum transport model for thixotropic liquids
Description
    Thixotropic viscosity momentum transport model based on the evolution of
    the structural parameter \f$ \lambda \f$:

        \f[
            \frac{D\lambda}{Dt} = a(1 - \lambda)^b - c \lambda \dot{\gamma}^d
        \f]

    The viscosity is then calculated using the expression

        \f[
            \nu = \frac{\nu_{\infty}}{{1 - K \lambda}^2}
        \f]

    Where the parameter K is given by:

        \f[
            K = 1 - \sqrt{\frac{\nu_{\infty}}{\nu_{0}}}
        \f]

    Here:
    \vartable
        \lambda         | structural parameter
        a               | model coefficient
        b               | model coefficient
        c               | model coefficient
        d               | model coefficient
        \dot{\gamma}    | stress rate [1/s]
        \nu_{0}         | limiting viscosity when \f$ \lambda = 1 \f$
        \nu_{\infty}    | limiting viscosity when \f$ \lambda = 0 \f$
    \endvartable

    Reference:
    \verbatim
        Barnes H A, 1997.  Thixotropy - a review.  J. Non-Newtonian Fluid
        Mech 70, pp 1-33
    \endverbatim
2020-12-31 11:36:25 +00:00
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2020-12-10 16:31:18 +00:00