72
2
< x
h
. Within this, we consider a motion of the system under consideration in the case
where the lineal-located force which moves with the constant velocity
V
acts on its free face plane
of the plate-layer. Assume that the plane-strain state in the plate and the two-dimensional flow of
the
fluid take place in the
1 2
Ox x plane.
The equations of the plate we take within the scope of the linear theory of elastodynamics,
i.e., as follows:
2
2
0
11
12
1
1
11
2
2
1
2
1
,
u
u
x
x
x
t
2
2
0
12
22
2
2
11
2
2
1
2
1
.
u
u
x
x
x
t
11
1
11
1
22
)
2
,
(
11
22
22
22
(
2
)
,
12
12
,
2
1
11
1
u
x
,
2
22
2
u
x
,
1
2
12
2
1
1
2
u
u
x
x
. (1)
Note that in Eq. (1) the conventional notation is used.
According to [6], we consider the field equations of motion of the Newtonian compressible
viscous fluid: the density, viscosity constants and pressure of which are denoted by the upper index
(1). Thus, the linearized Navier-Stokes and other field equations for the fluid are:
2
(1)
(1)
(1)
(1)
(1)
0
(
)
0
j
i
i
j
j
i
j
i
v
v
v
p
t
x x
x
x x
,
(1)
(1)
0
0
j
j
v
t
x
,
(1)
(1)
(1)
2
ij
ij
ij
T
p
e
,
1
2
1
2
v
v
x
x
,
1
2
j
i
ij
j
i
v
v
e
x
x
.
(1)
2
0
(1)
p
a
. (2)
where
(1)
0
is the fluid density before perturbation. The other notation used in Eq. (2) is also
conventional.
Assuming that
(1)
11
22
33
(
) 3
p
T
T
T
, we obtain that
(1)
(1)
2
/ 3
. Moreover, we
assume that the following boundary and contact conditions are satisfied:
2
21
0
0
x
,
2
22
0
1
0
(
)
x
P
x
Vt
,
2
2
1
1
x
h
x
h
u
v
t
,
2
2
2
2
x
h
x
h
u
v
t
,
2
2
21
21
x
h
x
h
T
,
2
2
22
22
x
h
x
h
T
, (3)
where
( )
is the Dirac delta function.
This completes the formulation of the problem. For the solution of this problem, we use the
moving coordinate system
1
1
'
x
x
Vt
,
2
2
'
x
x
(below we will omit the upper prime on the new
moving coordinates) and replacing the derivatives
( )
t
and
2
2
( )
t
with
1
V
x
and
2
2
2
1
V
x
, respectively, we obtain the corresponding equations and boundary and contact
conditions for the sought values in the moving coordinate system. For the solution to these
equations, we employ the exponential Fourier transformation
with respect to the
1
x coordinate
1
2
1
2
1
( ,
)
( ,
)
isx
F
f
s x
f x x e
dx
.
(4)