Hydrostatic Force on a submerged surface The other important utility of the hydrostatic equation is in the determination of force acting upon submerged bodies. Among the innumerable applications of this are the force calculation in storage tanks, ships, dams etc.
| Figure 2.13 : Force upon a submerged object |
First consider a planar arbitrary shape submerged in a liquid as shown in the figure. The plane makes an angle
with the liquid surface, which is a free surface. The depth of water over the plane varies linearly. This configuration is efficiently handled by prescribing a coordinate frame such that the y-axis is aligned with the submerged plane. Consider an infinitesimally small area
at a (x,y). Let this small area be located at a depth
from the free surface. From
Eq.2.18 we know that
 | (2.30) |
where
is the pressure acting on the free surface. The hydrostatic force on the plane is given by,
The integral,
is the first moment of surface area about x axis. If
is the y-coordinate of the centroid of the area we have,
 | (2.32) |
Consequently, Eq. 2.31 is rewritten as
 | (2.33) |
where
and
is the pressure acting at the centroid.
موضوع: 1- تقرير عن center of pressure 
2008-09-23, 6:56 pm
