Using CFD to determine scale effects on current loads of offshore vessels in side-by-side configuration

The scale effects and the shielding effects on the current loads for typical offshore vessels in side-by-side configuration are investigated using model tests and CFD calculations. Model tests have been carried out in a water basin to obtain reference data including shielding effects. Numerical verification for model- and full-scale Reynolds number is carried out to quantify the numerical uncertainty of the CFD results. Validation of the numerical results is performed by comparing the numerical results at model-scale Reynolds number to the model-test results. Reynolds scale effects are investigated by comparing the numerical results at model-scale and full-scale Reynolds number. Based on the results presented in this paper it is concluded that using CFD calculations the current loads on two vessels in side-by-side configuration can be obtained with acceptable accuracy. The calculated results are within 10% compared with the measured results for most headings. Comparing the numerical results at full-scale Reynolds number with the numerical results at model-scale Reynolds number it can be concluded that scale effects on current loads are important to consider in mooring and approach studies. Significant reduction is found for friction dominated forces. The differences for pressure dominated forces are smaller.