Environmental Engineering Reference
In-Depth Information
2.9.2 Floating Objects
Assuming that an object has a rigid inner structure, the force on each BP (boundary
particle) is computed by summing the contribution of each FP (fluid particle) in the
area of influence. The force per unit mass on a given boundary particle
k
may be
expressed as
f
k
=
f
ka
(19)
a
∈
FPs
where
f
ka
is the force per unit mass exerted by FP
a
on BP
k
. Taking into consider-
ation the principle of equal and opposite action and reaction, the force exerted by a
FP on each BP is given by
m
k
f
ka
=−
m
a
f
ak
(20)
which allows estimating the force exerted on the moving body.
For themotion of themoving body, the following equations of rigid body dynamics
are used:
M
d
V
d
t
=
m
k
f
k
,
(21a)
k
∈
BPs
I
d
d
t
=
m
k
(
r
k
−
R
0
)
×
f
k
,
(21b)
k
∈
BPs
where
M
is the mass of the body,
I
is the moment of inertia,
V
is the velocity of the
object,
is the rotational velocity and
R
0
is the position of the centre of mass.
Each boundary particle has a velocity given by
ʩ
u
k
=
V
+
ʩ
×
(
r
k
−
R
0
).
(22)
The BPs within the rigid body are then advanced in time by integrating Eq. (
22
).
3 Validation Case
The reliability of DualSPHysics is investigated with a standard free-surface bench-
mark test for SPH flows, reproducing the SPHERIC Benchmark Test Case #2 (
http://
The experiment described in Kleefsman et al. (
2005
) consists of a dam break flow
impacting an obstacle. This experiment is considered a valuable benchmark for the
SPH free-surface flow community.
The initial setup of the experiment is depicted in Fig.
1
. The tank is 3.22m long,
1m wide and 1m tall. The volume of water is 1.228m long, 1m wide and 0.55m
tall and it is initially confined at one end of the tank with a retaining wall that is
Search WWH ::
Custom Search