Discussion on Session 4: Forcing
After the general criticism of Morisons Equation and non spectral data analysis methods I wish to confirm that, in full scale, real sea, measurements there has been a remarkable degree of agreement between Morison formula computations of force and measurements on a wave by wave basis. This is found when the measurements are clearly in either the drag or the inertia regimes; when the individual waves are of significant magnitude in a storm, and the appropriate coefficients are applied taking into account the Re and Kc numbers. Problems arise in the generally unimportant overlap phase between drag and inertia when the load is past its maximum, or in uncertain flow regimes. It is acknowledged that this can be of scientific interest and be of engineering concern in some situations, but it was not generally an important engineering problem. The fact is that Morisons Equation does a good job when applied appropriately and should not be lightly discarded in favour of complex partial solutions.