We recently wrote about a team of marine engineers battling against a process called cavitation while trying to break the outright speed sailing record. The pesky phenomenon occurs across turbine blades – or, in this case, hydrofoil blades – where rapid changes in pressure create tiny bubbles that collapse with huge force causing turbulence and even blade degradation.
So it was interesting to see a discussion of the then recently discovered process in a research article in the February 1932 edition of The Engineer in the context of steam turbines.
’The problem of calculating the stresses produced in a plate by the impact of a drop of fluid is not one that lends itself to any simple mathematical solution, and there appear to be very few data available on the subject,’ said the author FW Gardner.
“A phenomenon that involves the collapse of a vacuous cavity”
’It is known that extremely high pressures may be produced by the hammer action of cavitation, a phenomenon that involves a sudden collapse of a vacuous cavity in a fluid medium.
’If therefore a drop were to strike a blade which had surface irregularities in such a manner that a vacuous cavity was enclosed and this cavity were then to collapse, pressures of a much higher order than those attributable to direct impact could result.’
The lengthy paper goes on to describe these ’irregularities’ in great detail with accompanying micrographs.
The Engineer in 2012 is now a more ’generalist’ title, reporting on the technological fruits of such research insights, but it certainly brings to mind the phrase: standing on the shoulders of giants.
Although some of our technologies seem light years ahead of the inter-war years they were only possible because of the body of research that came before.