Hydrodynamic Coefficients for Array of Tubular Cylinders

Hydrodynamic coefficients for groups of tubular cylinders subjected to
regular waves were experimentally investigated in this study. The
experiments were carried out at Universiti Teknologi PETRONAS
wave tank. The experimental hydrodynamic forces on tubular
cylinders were measured using wave force sensors, while the
theoretical values were estimated using Morison equation. The effects
of neighboring cylinders, spacing between the pipes, wave frequency
and wave amplitude on the hydrodynamic coefficients of tubular
cylinders were analyzed. In this study, the model cylinders were fixed
to the soffit of the wave tank bridge as cantilevered beams. The tubular
cylinders covered in this study are 1.23 m long galvanized steel pipes
with 34 mm diameter and 2.5 mm wall thickness. The immersed length
of the cylinder was 850 mm. The pipes were subjected to regular
waves with maximum wave height of 100 mm, and the Keulegan-
Carpenter number (KC) varied from 9.25 to 14.97. The obtained
inertia and drag coefficients are in fair agreement with API and PTS
specifications.