Rayleigh-Taylor Instability

For the best of web assignment, I chose a video that showcases the fluid phenomena termed the Rayleigh-Taylor Instability. I think it best exemplifies the art and science of flow visualization due to the simplicity of the experiment and how easily it showcases one of the many wonders of fluids. The video was taken by Dr. Jens Niemeyer, a Professor of Astrophysics and YouTuber who in the past has made several videos showcasing various fluid phenomena.

Within the video, hot blue liquid is inserted into a cold cup of water which initially produces no noticeable effects other than just floating at the surface of the water. However, over time, the blue liquid sinks down and sprouts mushroom-like shapes that slowly elongate over time. This is due to how the blue liquid becomes denser as it cools down compared to the cold water below it and in combination with the effects of gravity, causes the denser fluid to sink. This effect is known as the Rayleigh-Taylor Instability which occurs when there is an interface between two fluids containing differing densities. This instability causes the denser fluid to displace the lighter one and as a result, the lighter fluid will exert an upward buoyant force. The mushroom or finger-shaped trails generated from the denser fluid are a common effect and indicative of the Rayleigh-Taylor Instability.

In terms of art, it visually looks very simple yet interesting, especially with the mushroom-like sprouts that develop. One could even say it’s therapeutic to watch how slowly this effect develops. However, I would definitely consider experimenting with several more colors in order to get a more grand or aesthetically pleasing effect. I think even testing it with several more fluids with larger differences in density could possibly generate an even more chaotic result, especially in combination with correct lighting, color, and a higher-quality camera. However, overall, I just appreciate how something as simple as two fluids mixing can showcase one of the many fluid phenomena in our world.

Sources

Photo Credits: By Dr. Jens Niemeyer in 2015 (Taken from within the video – Citation below)

Video Credits: Niemeyer, J. (2015). Rayleigh-Taylor Instability. YouTube. YouTube. Retrieved September 7, 2023, from https://www.youtube.com/watch?v=yabqo7VFTYs&ab_channel=JensNiemeyer.

References

[1] Sharp, D. H. (1984). An overview of Rayleigh-Taylor instability. Physica D: Nonlinear Phenomena, 12(1–3), 3–18. https://doi.org/10.1016/0167-2789(84)90510-4