# PorousFlowDarcyVelocityMaterial

This Material calculates the Darcy velocity for all phases

This Material computes the Darcy velocity of all phases in the PorousFlow system. The Material properties are evaluated at the quadpoints (at_nodes = false). The Darcy velocity of a phase is: (1) where is the permeability tensor, is the relative permeability, is the viscosity, is the porepressure, is the density and is the gravitational acceleration. Hence, this Material requires many other Materials: permeability, relative permeabilities, etc.

An example of the syntax is:

# Basic advection of u in a 1-phase situation
#
# density * gravity = 4 * 0.25
# grad(P) - density * gravity = -3
# permeability = 5
# viscosity = 150
# so Darcy velocity = 0.1
[Mesh]
type = GeneratedMesh
dim = 1
nx = 10
xmin = 0
xmax = 1

The declaration of the Material name is:

    _darcy_velocity(declareProperty<std::vector<RealVectorValue>>("PorousFlow_darcy_velocity_qp")),
(modules/porous_flow/src/materials/PorousFlowDarcyVelocityMaterial.C)

This Material also computes the derivatives of the Darcy velocities with respect to all the PorousFlow variables, for use by Kernels, etc, to construct the Jacobian.

## Input Parameters

• PorousFlowDictatorThe UserObject that holds the list of PorousFlow variable names

C++ Type:UserObjectName

Options:

Description:The UserObject that holds the list of PorousFlow variable names

• gravityGravitational acceleration vector downwards (m/s^2)

C++ Type:libMesh::VectorValue

Options:

Description:Gravitational acceleration vector downwards (m/s^2)

### Required Parameters

Default:False

C++ Type:bool

Options:

• boundaryThe list of boundary IDs from the mesh where this boundary condition applies

C++ Type:std::vector

Options:

Description:The list of boundary IDs from the mesh where this boundary condition applies

• computeTrueWhen false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

Default:True

C++ Type:bool

Options:

Description:When false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

• blockThe list of block ids (SubdomainID) that this object will be applied

C++ Type:std::vector

Options:

Description:The list of block ids (SubdomainID) that this object will be applied

### Optional Parameters

• enableTrueSet the enabled status of the MooseObject.

Default:True

C++ Type:bool

Options:

Description:Set the enabled status of the MooseObject.

• use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

Default:False

C++ Type:bool

Options:

Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

• control_tagsAdds user-defined labels for accessing object parameters via control logic.

C++ Type:std::vector

Options:

Description:Adds user-defined labels for accessing object parameters via control logic.

• seed0The seed for the master random number generator

Default:0

C++ Type:unsigned int

Options:

Description:The seed for the master random number generator

• implicitTrueDetermines whether this object is calculated using an implicit or explicit form

Default:True

C++ Type:bool

Options:

Description:Determines whether this object is calculated using an implicit or explicit form

• constant_onNONEWhen ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeSubdomainProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped

Default:NONE

C++ Type:MooseEnum

Options:NONE ELEMENT SUBDOMAIN

Description:When ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeSubdomainProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped

• output_propertiesList of material properties, from this material, to output (outputs must also be defined to an output type)

C++ Type:std::vector

Options:

Description:List of material properties, from this material, to output (outputs must also be defined to an output type)

• outputsnone Vector of output names were you would like to restrict the output of variables(s) associated with this object

Default:none

C++ Type:std::vector

Options:

Description:Vector of output names were you would like to restrict the output of variables(s) associated with this object