Pump settings
The Pumping group controls the unsteady cycle — frequency, leg stroke, pitch and automatic optimum search.
Parameters
| Control | Meaning | Typical range |
|---|---|---|
| Frequency | cycles per second | ~0.8–1.4 Hz (dock start) |
| Leg amplitude | front wing stroke | limited by ride height / mast |
| Pitch amplitude | additional pitch in the cycle | keep moderate |
| Pitch phase | heave ↔ pitch offset (degrees) | 0° = in phase |
Frequency
Pumping faster: lift lags (Theodorsen), power and stall risk rise, net thrust can drop.
Leg amplitude
More stroke → stronger angle-of-attack swing and more thrust on the downstroke — costs energy and can stall the wing.
Pitch
Matched to up/down motion, pitch can smooth or amplify angle of attack. Too much pitch: unnecessary drag and stall peaks.
Find best operating point
The button runs a local grid search over frequency, leg stroke, pitch amplitude and pitch phase. Results land in the pump sliders.
Not a global optimum
The search finds a favorable point near sensible starting values — not guaranteed to be the absolute optimum over all parameters.
Animation (panel A)
Below panel A:
- Play/Pause — animation only while the foil sustains
- Phase scrubber — scrub through the pump cycle manually
Panel B and force vectors in panel A stay in sync with phase.
What you should see
After Find best operating point:
- Pump power metric drops if a sustaining point was found
- Panel B shows smoother heave / α curves
- Foil carries badge stays green
No sustaining point → message “No sustaining pump operating point found” — adjust setup or weight.