From: Wolfgang Bangerth <bangerth@math.tamu.edu>
Date: Sun, 24 Apr 2011 18:56:01 +0000 (+0000)
Subject: Discuss one other point.
X-Git-Tag: v8.0.0~4115
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a641b17e2216306b72c3666e5fe761c72c0e1729;p=dealii.git

Discuss one other point.


git-svn-id: https://svn.dealii.org/trunk@23642 0785d39b-7218-0410-832d-ea1e28bc413d
---

diff --git a/deal.II/examples/step-46/doc/intro.dox b/deal.II/examples/step-46/doc/intro.dox
index 33688de8ff..e1c4cccf96 100644
--- a/deal.II/examples/step-46/doc/intro.dox
+++ b/deal.II/examples/step-46/doc/intro.dox
@@ -428,6 +428,15 @@ We will consider the following situation as a testcase:
 
 @image html step-46.layout.png
 
+As discussed at the top of this document, we need to assume in a few places
+that a cell is either entirely in the fluid or solid part of the domain and,
+furthermore, that all children of an inactive cell also belong to the same
+subdomain. This can definitely be ensured if the coarse mesh already
+subdivides the mesh into solid and fluid coarse mesh cells; given the geometry
+outlined above, we can do that by using an $8\times 8$ coarse mesh,
+conveniently provided by the GridGenerator::subdivided_hyper_rectangle
+function.
+
 The fixed boundary at the bottom implies $\mathbf u=0$, and we also
 prescribe Dirichlet conditions for the flow at the top so that we get
 inflow at the left and outflow at the right. At the left and right