doco idaholab#12903

framework/doc/content/source/bcs/ADFunctionNeumannBC.md

@@ -0,0 +1,37 @@
+# ADFunctionNeumannBC
+
+!syntax description /BCs/ADFunctionNeumannBC
+
+## Description
+
+`ADFunctionNeumannBC` is a generalization of [`ADNeumannBC`](/ADNeumannBC.md) which is used
+for imposing flux boundary conditions on systems of partial
+differential equations (PDEs) where the flux is represented by a
+spatially- and temporally-varying MOOSE [`Function`](/Functions/index.md).  That is, for a
+PDE of the form
+\begin{equation}
+\begin{aligned}
+  -\nabla^2 u &= f && \quad \in \Omega \\
+  u &= g(t,\vec{x}) && \quad \in \partial \Omega_D \\
+  \frac{\partial u}{\partial n} &= h(t,\vec{x}) && \quad \in \partial \Omega_N,
+\end{aligned}
+\end{equation}
+where $\Omega \subset \mathbb{R}^n$ is the domain, and $\partial
+\Omega = \partial \Omega_D \cup \partial \Omega_N$ is its boundary, a
+`ADFunctionNeumannBC` object can be used to impose condition (3) if the
+function is well-defined for all relevant times and $\vec{x} \in
+\partial \Omega_N$. In this case, the `function` parameter corresponds
+to a MOOSE `Function` object which represents the mathematical
+function $h(t,\vec{x})$, and the user must define one or more sidesets
+corresponding to the boundary subset $\partial \Omega_N$ via the
+`boundary` parameter.
+
+## Example Input Syntax
+
+!listing test/tests/bcs/ad_function_neumann_bc/test.i block=BCs
+
+!syntax parameters /BCs/ADFunctionNeumannBC
+
+!syntax inputs /BCs/ADFunctionNeumannBC
+
+!syntax children /BCs/ADFunctionNeumannBC

framework/doc/content/source/bcs/ADNeumannBC.md

@@ -0,0 +1,36 @@
+# ADNeumannBC
+
+!syntax description /BCs/ADNeumannBC
+
+## Description
+
+`ADNeumannBC` is the simplest type of `ADIntegratedBC`, and is used for
+imposing flux boundary conditions on systems of partial differential
+equations (PDEs). This class is appropriate to use for PDEs of the
+form
+\begin{equation}
+\begin{aligned}
+  -\nabla^2 u &= f && \quad \in \Omega \\
+  u &= g && \quad \in \partial \Omega_D \\
+  \frac{\partial u}{\partial n} &= h && \quad \in \partial \Omega_N,
+\end{aligned}
+\end{equation}
+where $\Omega \subset \mathbb{R}^n$ is the domain, and $\partial
+\Omega = \partial \Omega_D \cup \partial \Omega_N$ is its boundary. In
+this case, a `ADNeumannBC` object is used to impose the condition (3) on
+the subset of the boundary denoted by $\partial \Omega_N$. The `value`
+parameter corresponds to the constant $h$, and the user must define
+one or more sidesets corresponding to the boundary subset $\partial
+\Omega_N$.  The normal derivative notation is $\frac{\partial
+u}{\partial n} \equiv \nabla u \cdot \hat{n}$, where $\hat{n}$ is the
+outward unit normal to $\partial \Omega_N$.
+
+## Example Input Syntax
+
+!listing test/tests/bcs/ad_1d_neumann/1d_neumann.i start=[./right] end=[../] include-end=true
+
+!syntax parameters /BCs/ADNeumannBC
+
+!syntax inputs /BCs/ADNeumannBC
+
+!syntax children /BCs/ADNeumannBC

framework/src/bcs/ADFunctionNeumannBC.C

@@ -9,6 +9,8 @@
 
 #include "ADFunctionNeumannBC.h"
 
+#include "Function.h"
+
 registerADMooseObject("MooseApp", ADFunctionNeumannBC);
 
 defineADValidParams(ADFunctionNeumannBC,