The Aqwa time domain results at 0.33 rad/s (T=19.039955s, head sea) seem normal, comparing to the RAOs generated by Hydrodynamic Diffraction. As shown below, the surge, heave and pitch RAOs (from HD) and responses (from HTR) are plotted. The amplitude of the time history of the pitch response is about 1.54 degrees, the equivalent RAO is about 1.54/1.12=1.375 degree/m, the interpolated pitch RAO by Hydrodynamic Diffraction at that frequency is greater than 1.0 degree/m. Please check the pitch time domain response of the reference paper. From the graph you showed on July 30, the amplitude of the time history of pitch response from the reference is about 0.8 degree, the equivalent RAO (if the wave amplitude is 1.12m) is about 0.7 degree/m.
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