Validation of full-scale delivered power CFD simulations

Roughness effect modelling for wall resolved RANS – Comparison of methods for marine hydrodynamics

“…The correlation factor is also investigated in Orych et al (2021) for another ship with similar conclusions. Schultz (2007) proposes a variable AHR/k S factor which depends on roughness height and type.…”

“…This has often caused numerical problems and has prevented the use of CFD at full-scale. However, with the present development of the numerical methods in CFD, this problem can be solved, see e.g., Orych et al (2021).…”

Scaling of wetted-transom resistance for improved full-scale ship performance predictions

“…Therefore, the full-scale FS RANS computations included the hull roughness effect, which affects the boundary layer, the pressure distribution, and the wave pattern around the stern. The roughness is implemented by a modification of the boundary conditions for the specific dissipation rate (𝜔) and the turbulent kinetic energy (𝑘) as explained by Orych et al (2021). The roughness value used for the computations is quantified by the sand grain roughness equivalent to the standard hull roughness value recommended by ITTC (2021a).…”

Hydrodynamics Performance Prediction of a Full-Scale Ship

“…Based on [19], the law of the wall with wall roughness can be written as: (4) where u [m/s] is the mean velocity, uτ = (τω/ρ) 1/2 [m/s] define the friction velocity in which τω [kg/ms2] is the wall shear stress and ρ [kg/m3] is the fluid density, y + = yuτ/ν represents the non-dimensional length where y is the normal distance from the wall and ν [m 2 /s] is the kinematic viscosity. Regarding B, it is defined according to Ligrani and Moffat [20] as: (5) where k = 0.41, C = 5. in which the values for Hr, S and Hr, R depends on the roughness geometry characteristics.…”

“…The results discussed during the workshop have been synthetised by Ponkratov [3]. CFD studies on the full-scale hydrodynamic performances prediction and validations have been reported by Orych et al [4], Niklas and Pruszko [5], Jasak et al [6], Pacuraru et al [7]. An extensive study based on the comparison of up to 78 sea trials to the predictions made by combined CFD/EFD methods was presented in by Korkmaz et.…”