Dear Zahid,
The “odd” square shape you are seeing in the time series is likely due to the small round-off error that results from the fact that FAST is only outputting 4-digits of precision based on the setting of OutFmt = “ES10.3E2” in FAST’s primary input file. My guess is that the shape would look more rounded if you added at least one more digit of precision in the output format. See the following forum topic for more information on OutFmt: FAST Integrator, step size & precision.
I’ve sent you the “Unofficial FAST Theory Manual” by e-mail.
I don’t have copy of the MoorDyn input file for OC3-Hywind model of Test24, but it is probably not too difficult to make one yourself because the MAP++ and MoorDyn input files have many similarities.
Best regards,