Field experiment on random wave forces acting on vertical cylinders

The accuracy of the Morison equation for wave forces acting on cylinders was tested by conducting a field experiment at the Natural Ocean Engineering Laboratory (NOEL) using a database of about 69,000 individual wind waves. The test was conducted by comparing two stationary random forces as a function of time: F-a(t), the measured wave force, and F-c(t), the wave force calculated using the Morison equation. The particle velocity and acceleration components of the Morison equation were obtained using the linear theory of wind-generated waves from the directional wave spectrum obtained by measuring the wave elevation. The inertia coefficient C-in and drag coefficient C-dg are given as a function of the Keulegan-Carpenter number K-E and Reynolds number R-E for K-E in (0, 20) and R-E in (2 . 10(4). 2 . 10(5)). The trend of our data was compatible with the asymptotic values of C-in and C-dg suggested by Sarpkaya for large values of R-E. (c) 2011 Elsevier Ltd. All rights reserved.