Download full text - ELSA - Europa

The FSCR algorithm
Combination of FSA and UP, exploiting respective strengths.
• Search normal(s) by FSA: n 1
(n 2
).
• Search normal by UP: n p
.
• If FSA yields influence domain
composed only by mutually
opposite faces, we know that n p
is undetermined: keep n 1
(n 2
).
• In all other cases n p
is more accurate than n 1
(n 2
). If there is only one FSA
normal n 1
, we take n p
instead. Else there are two FSA normals n 1
, n 2
: we
correct them so that n p
is contained in the plane defined by n’ 1
, n’ 2
.
25
The case of rigid structures (FSR)
• When structural displacements are known to be negligible (rigid structures),
one may want to model only the fluid
• The compatibility condition simplifies to: v
F
in = 0
• The normal n is constant in time and
needs to be computed only once
• The geometric and equilibriumbased
methods may be used
unchanged, apart from suitable
simplifications
• Practical aspect: the automatic
FS directives dramatically
simplify the prescription of
boundary conditions in
geometrically complex cases
26
13