Would you really care for knowledge?

I told the story of L. few weeks back. The guy works for Chevron and came kind of to supervise my/our work. In two-phase flow of two immiscible liquids, in a horizontal pipe, both phases will remain perfectly separated. If you pump them, the flow will be stratified, although interfacial waves will develop at a very early stage (i.e. slow superficial velocities of each phase). If the superficial velocities of the phases are the same, and the mixture velocity sufficiently high, interfacial waves are observed. Why? What is the nature of those waves and the mechanism behind?

L. posed the question. I can say here, with no pretension nor to set any precedence, that I had asked such question myself before. In many papers and publications it is stated -lightly, I would say- that superficial waves develop from differences in the relative velocity of the phases. Nevertheless, it is a simple matter to observe that if the relative velocity is 0 (i.e., both phases move at the same speed or, in practical terms, at very similar ones), waves do grow when the mixture velocity (overall flow) is increased. So the question pops out naturally: why?

The day before my presentation L. must have been in Imperial College, where someone else suggested that the main reason for interfacial waves to develop is the difference in viscosity between phases. From there, the corresponding output of shear forces generates the so-called Yih instability. L. spoke of it as something new; and someone else was not even able to spell correctly Yeh, know nothing about him, in spite of being studying two-phase flows for one decade and a half.

Few days later I got surprised of learning that the Yih instability is based on a 1967-paper and today I was shock to discover that Chia-Shun Yih collected a large and interesting deal of fluid mechanics topics in a book as early as 1969; among that, a whole chapter dedicated to instabilities.

And I came to think of a science-fiction world where the useful knowledge is forgotten in old and carefully elaborated volumes, shut down under dusty hard-covers; a world where knowledge has been relegated to a second line. Could it be possible to have in the real world a constellation of researchers in academia fighting so badly for a position to the extend of acquiring experimental data and messing up with too-partial models for the sake of publication, ignoring the well-known, dedicated and genuine knowledge and clouding the ocean of wisdom? How much of the knowledge available are experts actually conscious of it?

I am sure I will expand and elaborate more this idea and come back to it some other time.

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