Second order wave kinematics 1. Input in SIMA 2. Spectra Input Wave spectrum This is the input wave spectra, for instance Jonswap with given Hs and Tp. Riflex estimates a minimum frequency fmin and a maximum frequency fmax. This is the lower and upper limits for the wave spectrum. \(f_{min}=fac_{min}*\omega_{peak}\) \(f_{max}=fac_{max}*\omega_{peak}\) facmin and facmin is spectrum dependent For numerical spectrum fmin and fmax is the first and last given frequency that and fmin and fmax is slightly adjusted to correspond with the frequency resolution The 2. order wave spectrum consists of Linear frequency wave energy spectrum Difference frequency wave energy spectrum Sum frequency wave energy spectrum 3. Pre-generation of kinematics Length of kinematics time series, T: Requested time series length Time step used in the pre-generation, Δt Time increment Frequency resolution = 1/(applied time series length) Applied time series length = N*Δt 4. Estimated parameters Sampling frequency \(f_s=\frac{1}{\Delta t}\) Nyquist frequency, \(f_{nyq}=\frac{1}{2\Delta t}=\frac{f_s}{2}\) N=number of steps 5. Spectra 6. Warning in Riflex (SIMA) if 2*fmax > fnyq Note: wmax= 2*fmax The user can only affect the sampling frequency, If Δt in reduced, the Nyquist frequency will increase, fs = 1/Δt SIMO Depth dependent hydrodynamic coefficients How to model sea floor and soil contact