Resolve published OWC OrificeModel piston-force gap #622

Published source limitation

The pinned Applications OWC/OrificeModel sends wave excitation, but not the existing piston reaction, into the flexible GBM state-space force input. The piston reaction appears in a separate reported-acceleration path. The unchanged published case is step-sensitive and can exceed its Mach warning threshold, so it remains qualified_motion; the strict parity badge count is unchanged.

Repository-local corrected case

The Python repository maintains the one-connection Simulink patch and source runner. CI starts from the pinned original Applications revision, copies the case, adds piston reaction to the GBM force input, and sets simu.dt=0.00015625 s while retaining dtOut=cicDt=nonlinearDt=morisonDt=0.005 s. The published Applications model is unchanged.

The 130-second repository-local source run generated 26,001 output samples and passed strict archive reproduction: largest array difference 3.96e-11 against a 1e-9 gate. Source PTO work is 864.422 J and peak Mach is 0.155, below the model's 0.3 warning threshold. The run also passed the independently advanced Python body, piston/PTO, pressure, flow, power, and work gate. Python PTO work is 865.042 J, a 0.0717% difference. The parity record gives all limits and observed gaps.

Disposition

The derived corrected case is maintained and tested within wec-sim-python by #627 and #641. Because the published Applications wiring is unchanged, its qualified_motion status remains. This follows the issue's documented fallback closeout: record the source limitation and retain qualified status rather than making Python's physical default omit piston force.