High-fidelity CFD simulation of wave run-up for single/multiple surface-piercing cylinders in regular head waves

The capabilities of CFDShip-Iowa V4.5 and V6.2 simulations for wave run-up for single/multiple surface-piercing cylinders in regular waves are assessed in conjunction with the ITTC OEC Workshop on VIV and Wave Run-up held in Nantes, France October 17⿿18, 2013. Statistical convergence and grid/domain/turbulence model sensitivity studies show uncertainty UI values are less than 1% for both the experiment/simulation data and grid/domain/turbulence model sensitivities are less than the facility bias UFB. Simulations are qualitatively validated using UFB and error E between experiment and simulation. Errors for single/four cylinder(s) are comparable with UFB and average error E¯ for the other CFD data of the workshop participants. Results from both V4.5 and V6.2 agree well with experiment and also show capabilities to apply for complex/large-scale problem and to describe detailed wave breaking/spraying for V4.5 and V6.2, respectively. Study on run-up profile shows mean wave elevations are similar to free surface elevations for a cylinder in a steady current. For wave steepness/wave length effect, 2nd to 1st harmonic ratio on the cylinder weather face decreases with steepness for short wave, but increases for long wave. Wave diffraction analysis shows that 2nd/3rd to 1st harmonic ratio in diffracted wave contour reach up to 18⿿41%/9⿿16% respectively. Due to interaction between cylinders, crest/trough heights increase 5⿿17%/4⿿10% for 4C, respectively. Study on vortex shedding shows short wave has insufficient time to develop periodic vortex shedding compared to long wave.