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81 lines
1.9 KiB
Plaintext
81 lines
1.9 KiB
Plaintext
"CFDEMproject Website"_lws - "Main Page"_main :c
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:link(lws,http://www.cfdem.com)
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:link(main,CFDEMcoupling_Manual.html)
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:line
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otherForceModel gravityEff command :h3
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[Syntax:]
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Defined in "couplingProperties"_CFDEMcoupling_dicts.html#couplingProperties
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dictionary.
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otherForceModels
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(
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gravityEff
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);
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gravityEffProps
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\{
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voidfractionFieldName "voidfraction";
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rhoPart number1;
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\} :pre
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{voidfraction} = name of the finite volume void fraction field :l
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{number1} = particle density :l
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:ule
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[Examples:]
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otherForceModels
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(
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gravityEff
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);
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gravityEffProps
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\{
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voidfractionFieldName "voidfraction";
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rhoPart 1500;
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\} :pre
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[Description:]
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An effective gravitational source term, {gravityEff}, that is necessery to drive
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the flow only incase of periodic box simulations.
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This source term is added to the momentum equation.
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In case of simulating periodic boxes and assuming "homogeneous no-flow condition"
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we will have:
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:c,image(Eqs/otherForceModels_gravityEff_pic1.jpg)
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This equation depicts that in "no-flow condition" static pressure gradient balances the mixture weight.
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Therefore, to derive the flow in periodic box simulations, a dynamic pressure gradient is defined as
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:c,image(Eqs/otherForceModels_gravityEff_pic2.jpg)
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If one replaces the static pressure gradient of the fluid momentum equation with
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:c,image(Eqs/otherForceModels_gravityEff_pic3.jpg)
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the fluid momentum equation solved in case of periodic box simulations will be
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:c,image(Eqs/otherForceModels_gravityEff_pic4.jpg)
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The {gravityEff} source term is the third term on the RHS of the momentum equation.
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Note that the gravitational body force of the fluid momentum equation is considered
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with this source term.
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In the basic implementation of {gravityEff}, first we calculate the density of
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the mixture and then the source term is calculated based on the third term on the
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RHS of the momentum equation.
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[Restrictions:]
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none
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[Related commands:]
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"otherForceModels"_otherForceModels.html
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