This image shows a multitude of Saffman-Taylor instabilities of dyed water (less viscous fluid) through honey (more viscous fluid). Originally injected through a hole in the top plate of a Hele-Shaw cell into the center of the honey, the water formed Saffman-Taylor instabilities emanating outward radially. However, after the water reached the end boundary of the honey it burst out and quickly surrounded the honey. When the injection syringe was removed, the change in pressure pulled water back into the honey, creating Saffman-Taylor instabilities directed radially inward, an effect I thought was unique compared to a typical Hele-Shaw cell experiment.
Credits: Michael Becerra (setup), Qisheng Lei (setup)
Photo Camera Settings:
Cannon EOS 1500D (T7 Rebel)