Last updated on July 13th, 2020 at 08:40 pm
Well, how many of you love to play or experiment with shampoos and soaps? If you are one of them then this article is like a treat to you all.
We often hear that science is all around us in our day to day life and it is also very true. But, it is surprising to know that the small things we happen to ignore demonstrate basic laws of science in a practical way. In today’s article, we are going to discuss something that’s very common yet we fail to observe it.
Try it out
Pour a steady flow of shampoo from a height of 30cm about the surface. Make sure that you try to pour it at a single point itself. What is expected to be observed? A heap of shampoo on the surface, true but, it is also accompanied by something strange as well. Have a look-
Did you observe the enigmatic and peculiar stream of jet-like steam emanating from the pile of shampoo? This is called Kaye Effect and is observed thin shear-thining fluids. By far in practical life, it has been observed in shampoos only, but other shear-thinning fluids may also show Kaye Effect under suitable conditions.
What is the Kaye Effect?
The discovery of the Kaye Effect dates back to 1963 when British engineer Alan Kaye first observed this remarkable behavior while working with complex organic liquids. However, a comprehensive understanding of this phenomenon remained elusive until 2006 when Dutch researchers conducted innovative experiments to shed light on the underlying mechanisms.
What is Shear-Thining?
In practice, the majority of fluids deviate from Newtonian behavior, meaning that their viscosity varies with shear rate, exhibiting either shear thinning or shear thickening characteristics. Unlike Newtonian fluids, non-Newtonian fluids demonstrate a non-linear relationship between shear stress and shear rate.
Shear thinning fluids exhibit a decrease in viscosity as the shear rate increases. These fluids, also referred to as pseudo-plastic fluids, are commonly encountered in industrial and biological applications. Examples of shear thinning fluids include ketchup, paints, and shampoo.
Explanation
Most of the time, the shampoo just forms a heap on the bottom of the surface, something like this:
However, sometimes the formation of a dimple is seen at the top of the pile. This is due to the fact that the jet of the falling shampoo has some momentum and exerts a force on the heap. Subsequently, a delicate layer of fluid with reduced viscosity develops within the dimple, creating a lubricating barrier between the heap and the descending stream, effectively preventing their fusion. The stream gets a ramp-like structure to get deflected and launches from the dimple like a ski jumper: This in accordance with conservation of momentum as extra in coming shampoo is ejected out.
Why there is a time lag between the jets?
Once the excess incoming shampoo stream is discharged, the dimple gradually refills, forming a heap, and the process repeats cyclically. Consequently, there is a temporal gap between the outgoing bursts of shampoo.
Research and Applications:
Scientists and engineers have conducted numerous studies to understand the underlying mechanisms behind the Kaye Effect. Experimental investigations, theoretical analyses, and computational simulations have contributed to unraveling the complexities of this phenomenon. The findings have practical implications in various fields, including inkjet printing, fuel atomization, and biomedical applications.
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Abhijeet is a 4th-year Undergraduate Student at IIT Kharagpur. His major inclination is towards exploring the science behind the things of our day-to-day life.
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Abhijeet Mahatohttps://www.scilynk.in/author/abhijeet-mahato/
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Abhijeet Mahatohttps://www.scilynk.in/author/abhijeet-mahato/
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Abhijeet Mahatohttps://www.scilynk.in/author/abhijeet-mahato/
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Abhijeet Mahatohttps://www.scilynk.in/author/abhijeet-mahato/
