Waves and threads

Stationary waves around a "boat" at the water surface only exist above 23 cm/s. When they appear, does the drag force on the boat suddenly increase? We address this old question on the wave drag using boats without a hull: namely nitrogen drops moving at the water interface without any other contact than the vapour/water interface.

In the second part, we move to another class of interfacial problems and study the analogy between the buckling of elastic rods and the instabilities of viscous liquid threads.