Hydraulic Structures: Fourth Edition
Darbyshire and Draper (1963) presented widely used charts (Fig. 14.14) for wave prediction, based on observations around Britain ...
Fig. 14.14 Fetch graphs for oceanic waters (Darbyshire and Draper, 1963) Fig. 14.15 Fetch graphs for coastal waters (Darbyshire ...
1 2 a^2 ∞ 0 E(f)df or 1 8 H^2 rms. (14.47) A fully developed sea is one for which the fetch and the duration of wind a ...
The wave energy in the JONSWAP spectrum is concentrated within a nar- rower band of frequencies and is more peaked than that giv ...
From equation (14.49), for the Pierson–Moskowitz spectrum, Hs0.447g1/2/π^2 f^2 m. (14.55) Numerical integration of the JONSWAP ...
and ^2 s N 1 1 N i 1 [ln(Hs) μs]^2. Before attempting to estimate the design wave height for a return period, we must fir ...
available over at least 30 years, long-term statistics are preferred. Extreme value statistics are dealt with comprehensively by ...
the bed and the cylinder, and the gap between the bed and the pipe, expressed as a ratio of the pipe diameter. The boundary laye ...
whereumis the maximum velocity. Using the above expressions, equation (14.63) results (in non-dimensional form) in CD| sint| s ...
organisms on the surface of the cylinder will undoubtedly affect the rough- ness and also the effective diameter of the cylinder ...
It is common practice to use Morison equation (14.63) for the in-line force for co-existing waves and currents, by replacing the ...
bottom of the cylinder causing alternate transverse or lift forces normal to the oscillatory flow direction. Transverse forces c ...
whereNis the number of Fourier components, CLnand (^) nare the nth lift coefficient and corresponding phase angle respectively. ...
sea bed and on the cylinder, dynamic boundary conditions on the free surface and the radiation conditions at infinity. Numerical ...
(Yuksel and Narayanan, 1994a) is reasonably satisfactory for the wave forces. However, the difficulty remains in the choice of a ...
used to describe the particle kinematics. Near the coast the linear theory may not be accurate enough, so that the forces are un ...
14.12 Vortex-induced oscillations 14.12.1 Vertical cylinders in currents The fluctuating forces exerted on the piles in the pres ...
VORTEX-INDUCED OSCILLATIONS 613 convenient measure of the damping is the logarithmic decrement, , which is defined as the natura ...
The natural frequency of a cantilever with effective mass meper unit length is fn0.56(EI/mel^4 )1/2 (14.76) whereEis the modulu ...
VORTEX-INDUCED OSCILLATIONS 615 14.12.2 In-line oscillations Experimental studies on the in-line response of flexible cylinders ...
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