Not sure if posted anywhere before? Very interesting publication about sinusoidal leading-edge on foils.. "Effect of Bio-Inspired Sinusoidal Leading-Edges on Wings" (2018)
Kujira front wing whale like tubercules probably have a significant effect on the foil's behavior, making the coefficient of lift more homogenous across all angles of attack, plus a softened and delayed stall.
Manuscript in free access online. In the conclusion :
"The stall characteristics for all of the models with modified leading-edges did not exhibit a dramatic, sudden loss in lift, but a more gradual, almost plateau of CLmax before a very gradual loss in lift. Although the sinusoidal leading-edge models do not have as high of a CLmax and CL is comparable or lower for most of the angles of attack up to 16?, the presence of the tubercles softens and delays stall. Additionally, after 16?, the sinusoidal leading-edge model exhibits a higher CL, as much as 25%. This gives the sinusoidal leading-edge design an expanded operating envelope of higher lift at higher angles of attack."