Hydrodynamic Coefficients and Depth Parameter

The in-line forces measured on a small section of a fixed vertical cylilnder in waves are analyzed to determine the effects of the hydrodynamic coefficients on the water depth parameter or the orbital shape parameter, Ω. The coefficients, C\dM, C\dD as well as an rms force coefficient, C\dF derived from these forces are found to be insensitive to the value of Ω in the range of Ω = 0.3 to 0.9. In an earlier study, it was shown from the test data that the values of C\dF at Ω = 0.9 were distinctly different from those at Ω = 0.3 - -0.7. Thus, the present study contradicts the results of the previous study. In the range of KC values of 0 - 40, however, the force coefficients compare well with U-tube experimental data.