Changeset 5765

Timestamp:

Sep 18, 2008, 11:03:45 AM (16 years ago)

Author:

ole

Message:

Updated ANUGA_flyer draftImproved caution regarding Transmissive_boundary following talks with Will Power and Biljana Lukovic

File:

• anuga_core/documentation/user_manual/anuga_user_manual.tex (modified) (1 diff)

anuga_core/documentation/user_manual/anuga_user_manual.tex

@@ -535 +535 @@
       momentum quantities assumed to be the second and third conserved
       quantities. A reflective boundary condition models a solid wall.
-    \item \textbf{Transmissive boundary}\label{def:transmissive boundary} Returns same conserved quantities as
+    \item \textbf{Transmissive boundary}\label{def:transmissive boundary} 
+      Returns same conserved quantities as
       those present in its neighbour volume. This is one way of modelling
       outflow from a domain, but it should be used with caution if flow is
       not steady state as replication of momentum at the boundary
-      may cause occasional spurious effects. If this occurs,
-      consider using e.g. a Dirichlet boundary condition.
+      may cause numerical instabilities propagating into the domain and 
+      eventually causing ANUGA to crash. If this occurs,
+      consider using e.g. a Dirichlet boundary condition with a stage value 
+      less than the elevation at the boundary.
     \item \textbf{Dirichlet boundary}\label{def:dirichlet boundary} Specifies
       constant values for stage, $x$-momentum and $y$-momentum at the boundary.