Fig. 1 Definition of the coordinate system More

Fig. 2 Flowchart for analysis More

Fig. 3 Sum-frequency wave forces varying with the mean frequency for different combinations of wave directions at θ 2 = 0 rad and Δ Ra = 0.2: ( a ) surge forces and ( b ) sway forces More

Fig. 4 Difference-frequency forces varying with the mean frequency for different combinations of wave directions at θ 2 = 0 rad and Δ Ra = 0.2: ( a ) surge forces and ( b ) sway forces More

Fig. 5 Mesh over a two-dimensional directional spectrum ( h = 100 m, H 1/3 = 1.0 m, ω p = 1.0 rad/s, θ p = 0.0 rad, s = 8) More

Fig. 6 Comparison of simulated spectra (symbols) and the target spectrum (curve) ( h = 100 m, H 1/3 = 1.0 m, ω p = 1.0 rad/s, θ p = 0.0 rad) More

Fig. 7 Directional functions for different directional spreading parameters s More

Fig. 8 Mesh grid of the truncated cylinder More

Fig. 9 Amplitude spectra of the second-order vertical forces for different incident principal heading directions of the storm waves ( θ 0 = 0.0 rad, s = 8, ω p = 1.0 rad/s) More

Fig. 10 Amplitude spectra of the second-order vertical force component forces for different incident principal heading directions of the storm waves ( θ 0 = 0.0 rad, s = 8, ω p = 1.0 rad/s): ( a ) F D ( 2 ) and ( b ) F I ( 2 ) + F W ( 2 ) More

Fig. 11 Definition diagram for the sum and the difference-frequency wavenumber: ( a ) k → p + k → 0 and ( b ) k → p − k → 0 More

Fig. 12 Amplitude spectra of the second-order wave forces in surge for different incident principal headings of the storm ( θ 0 = 0.0 rad, s = 8, ω p = 1.0 rad/s) More

Fig. 13 Amplitude spectra of the second-order forces in sway for different incident principal headings of the storm ( θ 0 = 0.0 rad, s = 8, ω p = 1.0 rad/s) More

Fig. 14 Amplitude spectra of the second-order forces for different directional spreading s : ( a ) surge forces and ( b ) vertical forces ( θ 0 = 0.0 rad, θ p = π , ω p = 1.0 rad/s) More

Fig. 15 Amplitude spectra of the second-order forces for different peak frequencies ω p : ( a ) surge forces and ( b ) vertical forces ( θ 0 = 0, s = 8) More

Fig. 1 Sketch of a realistic interface between porous medium and free flow More

Fig. 2 Sketch of the experimental layout for steady current through a porous medium More

Fig. 3 Comparisons of simulated and measured velocity profiles More

Fig. 4 Comparisons of simulated and measured turbulent kinetic energy More