SinNeumannBC.md|Numbat

# SinNeumannBC

Imposes a time-varying flux boundary condition $var element = document.getElementById("moose-equation-4d5ea286-44e1-471c-8cd6-48f10a87c47c");katex.render("\\frac{\\partial u}{\\partial n}=g(t)", element, {displayMode:false,throwOnError:false});$ , where $var element = document.getElementById("moose-equation-7cddfe41-f505-48d0-a33a-81e1fc3182f3");katex.render("g(t)", element, {displayMode:false,throwOnError:false});$ varies from an given initial value at time $var element = document.getElementById("moose-equation-e17e83ab-645e-49b4-a785-2b46d62559d4");katex.render("t=0", element, {displayMode:false,throwOnError:false});$ to a given final value over a specified duration.

Description

SinNeumannBC is an IntegratedBC which imposes a time-varying flux of the form $(1)var element = document.getElementById("moose-equation-1d4cf317-49d7-4ce6-a632-e0593dd9c0f9");katex.render(" g(t) = \\left\\{ \\begin{array}{ll} g_0 + (g_T - g_0) \\sin \\left( \\frac{\\pi t}{2T} \\right), & 0 < t \\leq T \\\\ g_T, & t \\geq T \\end{array} \\right.", element, {displayMode:true,throwOnError:false});$ where $var element = document.getElementById("moose-equation-16faafe3-817d-42c1-8c5b-51a563eb3d86");katex.render("g_0", element, {displayMode:false,throwOnError:false});$ and $var element = document.getElementById("moose-equation-5711d858-0ec7-44c1-9590-0d0ebb2d50a1");katex.render("g_T", element, {displayMode:false,throwOnError:false});$ are the initial and final values of $var element = document.getElementById("moose-equation-2bac2c87-5497-42ec-af9f-3cb09456f32a");katex.render("g", element, {displayMode:false,throwOnError:false});$ , respectively, and $var element = document.getElementById("moose-equation-c7bab0da-c47f-4602-9062-2f8a3d1aba7c");katex.render("T", element, {displayMode:false,throwOnError:false});$ is the final time. These values are controlled by the initial, final, and duration parameters, respectively. The value is applied on one or more sidesets specified by the boundary parameter and does not vary in space. This type of boundary condition is applicable to time-varying PDEs, for example: $var element = document.getElementById("moose-equation-6aa444fd-ae11-461e-9d27-d6115063af5e");katex.render("", element, {displayMode:false,throwOnError:false});$ \begin{aligned} \frac{\partial u}{\partial t} -\nabla^2 u &= f && \quad \in \Omega \\ \frac{\partial u}{\partial n} &= g(t) && \quad \in \partial \Omega \end{aligned} $var element = document.getElementById("moose-equation-94f3f2b1-0d3f-4374-9960-0e97e5e3747c");katex.render("", element, {displayMode:false,throwOnError:false});$ and is frequently used to "ramp" a difficult boundary condition to its final value over a short time interval, rather than imposing it instantaneously at time $var element = document.getElementById("moose-equation-769238a9-afd2-46bc-88bb-da8338b56543");katex.render("t=0", element, {displayMode:false,throwOnError:false});$ . This approach can make nonlinear solvers more robust by improving the initial guess used by the Newton iterations, as well as preventing the solver from converging to non-physical solutions in nonlinear PDEs.

Example Input Syntax

  [./right]
    type = SinNeumannBC
    variable = u
    boundary = 1
    initial = 1.0
    final = 2.0
    duration = 10.0
  [../]

Input Parameters

variableThe name of the variable that this boundary condition applies to
C++ Type:NonlinearVariableName
Description:The name of the variable that this boundary condition applies to
boundaryThe list of boundary IDs from the mesh where this boundary condition applies
C++ Type:std::vector
Description:The list of boundary IDs from the mesh where this boundary condition applies

Required Parameters

duration0The duration of the ramp
Default:0
C++ Type:double
Description:The duration of the ramp
initial0The initial value of the gradient on the boundary
Default:0
C++ Type:double
Description:The initial value of the gradient on the boundary
final0The final value of the gradient on the boundary
Default:0
C++ Type:double
Description:The final value of the gradient on the boundary

Optional Parameters

enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Description:Set the enabled status of the MooseObject.
save_inThe name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector
Description:The name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
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
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
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
Description:The seed for the master random number generator
diag_save_inThe name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector
Description:The name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
implicitTrueDetermines whether this object is calculated using an implicit or explicit form
Default:True
C++ Type:bool
Description:Determines whether this object is calculated using an implicit or explicit form

Advanced Parameters

vector_tagsnontimeThe tag for the vectors this Kernel should fill
Default:nontime
C++ Type:MultiMooseEnum
Description:The tag for the vectors this Kernel should fill
extra_vector_tagsThe extra tags for the vectors this Kernel should fill
C++ Type:std::vector
Description:The extra tags for the vectors this Kernel should fill
matrix_tagssystemThe tag for the matrices this Kernel should fill
Default:system
C++ Type:MultiMooseEnum
Description:The tag for the matrices this Kernel should fill
extra_matrix_tagsThe extra tags for the matrices this Kernel should fill
C++ Type:std::vector
Description:The extra tags for the matrices this Kernel should fill

Tagging Parameters

Description
Example Input Syntax
Input Parameters