Field experiment on random wave forces acting on vertical cylinders

Abstract 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 i n and drag coefficient C d g 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 i n and C d g suggested by Sarpkaya for large values of R E .

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