Impressive hummingbird aerodynamics in Durham, NH. They beat their wings at around 40 Hz (this is a Live Photo, so not very high frame rate). Check this link for a fun fact about hummingbirds from @nicolesharp.com

fyfluiddynamics.com/2021/05/how-...

Happy #FlumeFriday! I started making sand ripples in the environmental flows water tunnel at #UNH. The oscillatory flow pushes the sand at the crests back and forth and creates vortices downstream (leeward side) of the ripples.

A nearby example at a different angle to the wind.

Funneling ocean #waves on the coast of Maine near Ogunquit, about 1 hr after low tide.

After a ferry approaches #mackinacisland, some of the bow #waves generated by its high speed are reflected off the rubble breakwater and overlap with incident waves leading to interesting breaking patterns near shore.

Another hydraulic jump in Ithaca, NY on #flumefriday. A hydraulic jump occurs when water goes from a shallow, fast (supercritical) area to a deeper, slower (subcritical) area. The critical velocity and depth are reached when Froude number is at unity: v/(gh)^.5=1.

I saw melting #water flowing under ice. The time during which the water is in the camera field of view depends on how steep or how tortuous the water’s path is. #hydrology.

Thanks, Jack Powers, for helping us get the long-stroke wave tank running on this #FlumeFriday (see slo-mo video below). The way shoaling waves break depends on the beach slope, wave height, and wavelength in deep water (i.e. the Iribarren number).