Environmental Engineering Reference
In-Depth Information
Fig. 2.38 Allocation of bar elements and partially loaded areas [30]
- Owing to the combined linearised boundary condition at the surface of the water, the
hydrodynamic pressure - on both the positive pressure and the negative pressure side
of the structure - is defined exactly as far as the still water level. In reality the wave
contour represents the upper boundary for the wetted surface and for the hydro-
dynamic pressure and so the resulting differential pressures are roughly triangular
(Figure 2.39). As the wave contour changes over time, every interval must be
considered separately.
- The part of the hydrodynamic pressure (velocity pressure) dependent on the square
of the velocity vector is obtained by including the second-order terms of the
Bernoulli equation in the calculations (Figure 2.40). Flow velocities tangential to
the surface of the structural member generate negative pressures which, for example,
lead to a drop in the wave contour as it flows around the monotower.
2.6.5 Vertical cylinders (MacCamy and Fuchs)
The large-volume vertical cylinder has a special significance as a solitary structure and
also as a component of marine structures. It has therefore been thoroughly investigated
in the past, theoretically and experimentally. MacCamy and Fuchs devised one
important analytical method for ascertaining the diffraction of a primary wave around
a large-diameter vertical cylinder erected on the seabed [29].
