Thoughts on Liquid Air
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Thoughts on Liquid Air • Posted: Mar 24, 2019 10:57:14Comments WelcomeVote CoolPhotoblogsPurchase a PrintShare

Spring arrived this week. Plus, we gained an extra hour of daylight with the change of time in the week before. Despite distractions in the news, one is hard pressed to not take notice. More daylight and more sunshine catching our gaze. Warmer temperatures and the scent of change stirring our senses. Wherever we are, we cannot help but take pause migrating from shelter to shelter. And, what is it that most embraces us? It is the air.

Many of us know that water is a liquid. But probably, far fewer realize air is a liquid, too. Air flows, changes shape, and pretty much uniformly transmits internal pressure and heat throughout its containment, just like water and other fluids. The science of fluid dynamics attempts to describe and accurately predict the behavior of liquids.

The 2019 Formula 1 racing season began last weekend. The behavior of air plays a major roll in how those cars perform, both in how air flows over and around the vehicle and its brakes, and in how their engines gulp, burn, and expel air to power them, not to mention whether drivers have adequate oxygen to breath, laced with a minimum of toxic gases.

Sensor and/or software failure to accurately predict the behavior of air moving over wings and fuselage likely played a significant role in the crash of an Ethiopian airliner early the week before, killing all 157 aboard. French, FAA, and Boeing engineers are still trying to figure exactly what went wrong.

A new kind of hybrid jet/rocket engine began shakedown testing that same week in the UK. That new engine makes use of a very interesting air intake reportedly capable of cooling high speed incoming air by hundreds of degrees within a fraction of a second. The advantage there is that colder air is more dense, thus feeding more air in smaller volumes to the engine’s combustion process at higher altitudes where outside air is substantially thinner. How that air-cooler works has not yet been explained. But, my guess would be that British engineers are making use of a principle used in refrigeration wherein high pressure gas allowed to expand rapidly through a small opening drops significantly in temperature, which is how we get refrigerators and air-conditioners to work.

Temperature and pressure differentials also drive the winds we experience in the daily weather that surrounds us. Current reports are that upwards of 1000 people may have died last weekend when hurricane force winds ripped through Mozambique. High winds have plagued the US in recent weeks, too. A single tornado killed three generations of one family in rural Alabama.

Images above depict air in a significantly less dynamic state, reminding me of just how invigorating the scent of fresh spring air, the gloriousness of bright sunlight, and the calm promise of newly melted waters can be after the gray bitter cold and prolonged high winds many of us have experienced this winter. Those same images also remind me of how fascinating the physics of liquids can be. That old building pictured has most certainly endured significant stress due to liquid air moving around and through it. Those clouds in the background skate on currents of air. Grasses beside the water bend with the flow of air. And, the water itself ripples, or not, as air tickles its surface.

Check out how clouds get mirrored in the water. Have you ever seen a mirage? Blue sky and clouds will mirror off the calm surfaces of air, too.

Calm surfaces of air? Yes, the calm surfaces of air.

The physical world we inhabit is without a doubt endlessly fascinating, if only we open our minds to it. May you never find yourself walled off from wonder by your own distractions and preconceptions, or by the preoccupations and prejudices of others.

Tuesday, March 27th, 2018