DEVELOPING A FORMULA TO REPRESENT THE SECOND-ORDER WAVE EFFECTS ON MOORED FLOATING STRUCTURES

The effects of wave direction, frequency and the waterline shape of floating structures on the wave mean drift force formula have been considered separately by several authors but there isn't a general formula to take into account all of these effects. In this regard, Faltinsen’s wave drift force formula has been modified by adding finite draft coefficient. The results obtained from this formula which is dependent on wave frequencies, has been compared with Helvacioglu’s experiments favorably in high wave frequencies. Moreover, the influence of the current on the wave mean drift force has been taken into account by considering the current coefficient derived from the ship added resistance formula. In addition, the formula for the calculation of the wave drift damping has been extended to cover high wave frequencies as well as low wave frequencies. The results compared with asymptotic formula showed good agreement in the high frequency band.