High Speed Movies - Liquid flow

The movement of liquids is generally directed by the forces resulting from pressure, inertia, gravity/buoyancy, friction (=viscosity) and capillarity (=surface tension). Depending on the system under study, these forces act in different proportions, with a variety of typical flow patterns resulting. Gradually, representative examples will be collected and shown on this page (work in progress ...)

Movie #1: The "Strokkur" erupting, 2008

Technical Data (2 movies are presented)

Frame rate [fps]	300 ; 600
Resolution [px x px]	512x384 ; 432x192
Viewing duration [mm:ss]	00:47 ; 00:28
Realtime duration [s]	4.7 ; 1.4
Filesize [kB]	6055 ; 485

Download Quicktime Movie "CIMG2874_Strokkur_kleiner_Ausbruch_HS300.mov"

Download Quicktime Movie "CIMG2877_Strokkur_Ausbruch_HS600-2.mp4"
Please respect the copyright of the author!

Story/Action

A small eruption of the Strokkur gusher (Iceland) is observed. The water in the underground cavern is heated by the hot rocks, and eventually, a high pressure is built up, driving the water out of the "chimney". During the eruption, multiple jets can be seen, evolving with different speeds, and sometimes "overtaking" the previous ones. When a sufficient amount of water is driven out of the cavern, the pressure is reliefed, and the eruption ceases. Slowly, new, colder water pours into the cavern, and after a certain time required for re-filling and heating, a new eruption occurs.

Movie #2: Water drops on water surface, 2009

Technical Data

Frame rate [fps]	300
Resolution [px x px]	512 x384
Viewing duration [mm:ss]	00:07
Realtime duration [s]	0.7
Filesize [kB]	1217

Download Quicktime Movie "CIMG0026_Wassertropfen_HS300.mov"
Please respect the copyright of the author!

Story/Action

A drop of water impinges on a water surface. By displacing the still water from it's original place, a crown is formed around the impact hole. Small instabilities enable the surface tension to create single rounded spikes on the ring of the crown. When the gravity collapses the crown, the momentum propels a lance of water out of the central impact hole. In this special case, inside the tip of the lance, there are small bubbles of air, which were mixed in during the droplet impact. Also the lance head is rounded by the working of the surface tension. Sometimes, the lance breaks up into several individual droplets. When the lance collapses into the water surface, the cycle begins again in a similar way, as it was started by the droplet.

The scene was lighted with natural light on a cloudy day, enhanced with a 500W halogen lamp. To reduce motion blurring, the exposure time was reduced to 1/1250 seconds. An additional lens with 1 dioptrie was fitted in front of the camera objective for the close up shots.

Movie #3: Oil drops on water surface, 2009

Technical Data

Frame rate [fps]	600
Resolution [px x px]	432 x 192
Viewing duration [mm:ss]	00:28
Realtime duration [s]	1.4
Filesize [kB]	915

Download Quicktime Movie "CIMG0032_Oeltropfen_HS600.mov"
Please respect the copyright of the author!

Story/Action

Basically similar as the water droplet above, but the crown formed by the oil is very smooth (without spikes). When a second drop hits the tip of the ejected lance, a "chinese-hat" like structure is formed. The oil spot floats on the water, and the surface tension pulls it to a nearly perfect circular disk shape to minimize the boundary energy.

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