BOUNDARY
CONDITIONS
Polarization/Local
Axes
High voltage should be applied
on the center surface of the PZT two layers, and
Ground on the metal side surface. Choose the polarization
direction along the electric field direction.
Data -> Conditions -> Surfaces -> Geometry
-> Polarization (Cartesian) -> Define Polarization
(P1) (1,0) direction
Choose 3PointsXZ -> Center (0,0,0) -> Define
X axis by putting (0,1,0) -> Then define Z axis
by putting (1,0,0) -> Escape
Data -> Conditions -> Surfaces -> Geometry
-> Polarization (Cartesian) -> Define Polarization
(P2) (-1,0) direction
Choose 3PointsXZ -> Center (0,0,0) -> Define
X axis by putting (0,1,0) -> Then define Z axis
by putting (-1,0,0) -> Escape
Assign Polarization (Local-Axes P1 and P2) -> Choose
the PZT surface -> Finish
Potential
Data -> Conditions -> Lines -> Potential
0.0 (or Ground in ATILA 5.2.4 or higher version) -> Assign
the center line of the PZT -> Forced Potential
1.0 -> Assign the right- and left-side lines of
the PZT
Surface
Contraints
The bottom axisymmetric line
of the whole system (including water) - Y component
is clamped. The axisymmetric axis is taken along
x axis (This is the rule in ATILA!).
Data -> Conditions -> Lines -> Line Constraints
-> Y & Z components -> Clamped -> Assign
the Axisymmetric
X axis
Radiation
Boundary
Data -> Conditions -> Lines -> Line Constraints
-> X components -> Clamped -> Assign the left-side
PZT and Water lines
Radiation boundary is applied
not to reflect the water-propagating sound at this
boundary (like an anechoic wall). In this sense,
the radius of this water boundary is not essential.
To check the assignment -> Draw
-> All conditions -> Include local axes
MESHING 
Mapped Mesh
Meshing -> Structured -> Surfaces -> Select
all Surfaces -> Then Cancel the further
process
Meshing -> Structured -> Lines -> Enter number to
divide line -> Choose "1,
2, 4" for the lines -> Generate