fluid

Fire, Explosions, and Lymphatic Systems: Annual Review of Fluid Mechanics Volume 50

Suzanne K. Moses Volume Annoucement

Browse the Annual Review of Fluid Mechanics Volume 50 table of contents.

Before I get to the fire and explosions I want to highlight the lovely article “John Leask Lumley: Whither Turbulence?” by Leibovich and Warhaft that begins this volume.  This biography includes sections about Dr. Lumley’s love and appreciation for vintage cars and good food and wine as well as a look at his contributions to fluid mechanics. It’s a remarkable tribute and a worthwhile read.

Tohidi, Gollner, and Xiao wrote “Fire Whirls” which I found myself thinking about as I watched coverage of the California wildfires:

fl50-fire whirls

Throughout the literature, fire whirls have been identified by a variety of names, including devil, tornado, twister, whirlwind, or even dragon twist (Japanese). Regardless of the name, when the right combination of wind and fire interact, the result is an intensification of combustion with whirling flames that we call the fire whirl. Although the fire whirl or fire tornado shares some features with its atmospheric counterparts, it remains distinct in its source of buoyancy, combusting fuel, structure, and formation patterns. In nature, fire whirls are most often observed in mass fires. These include both large wildland (also known as forest fires or bushfires) and urban conflagrations, such as the burning of cities or towns…

fl50-detonationWhile action movie explosions make it seem easy, a controlled detonation that accomplishes more than looking good on film is difficult and complex to model. “High Explosive Detonation-Conifer Interactions” by Short and Quirk begins by explaining some of the complexity:

The dynamics of a given HE–confiner system depend on the pressure-loading properties of the explosive (magnitude and timescale), while in turn the structure and speed of the detonation reaction zone and the lateral confinement of explosive products are dependent on the material properties of the confining material, such as its density and sound speed. The ability to predict the motion of a detonation in an explosive system (known as the timing) and the response of the confiner to the HE detonation pressure loading depend on our ability to model and understand this detonation–confiner flow coupling…

I found “Lymphatic System Flows” by Moore and Bertram quite interesting especially as it explained the importance of several organs I’d always been curious about:

The lymphatic system as a functional whole includes several organs whose association as a system is not readily apparent. Lymphoid organs include the spleen, thymus, and tonsils; another vital component is the bone marrow where white cells are manufactured…. Functionally, the lymphatic vascular systemfl50-lymph runs in parallel to the blood venous system, in that both return fluids centrally. Lymphatic vessels carry lymph, which is largely water gathered from interstitial tissue spaces. Fluid appears in the interstitial spaces because blood capillary walls are somewhat leaky, allowing part of the aqueous component of blood to escape, along with some proteins…. The lymphatic vascular system scavenges this water and protein, ultimately returning it to the venous circulation via junctions with the subclavian veins at shoulder level. The maintenance of the interstitial milieu is one of its vital functions; if fluid is not returned to the blood system at the same rate as it leaves, the painful and debilitating condition of edema can develop.

The Annual Review of Fluid Mechanics, Volume 49

Suzanne K. Moses News

Take a look at the full table of contents for the Annual Review of Fluid Mechanics, Volume 49.

Volume 49 opens with a biography: “An Appreciation of the Life and Work of William C. Reynolds” by Moin and Homsy. Written by people who knew Reynolds and his work very well, it’s full of fond memories and appreciation for a teacher and friend. I especially liked this paragraph:

As a scientist, Reynolds was the ultimate independent thinker, a self-starter, do-it-yourselfer, a hands-on problem solver, and, in the most favorable sense of the term, a micromanager. In following his own intuition, Bill might have reinvented the proverbial wheel, but in the process he found novel and exciting ideas and designs that enriched the engineering field and inspired the people around him. He was a true believer in the familiar maxim (which he repeated quite often) that “if you want it done right, you had better do it yourself.” He designed his own house and once told one of us (G.M.H.) who was undertaking a similar venture that “sure, you’ll make mistakes, but they will be your mistakes.” Not a natural delegator, he immersed himself in many diverse projects with boundless energy and indefatigable enthusiasm. In the words of his son Russell, Bill felt that “anything worth doing was worth overdoing.”

cloud-top

One of my favorite things to do on planes is to stare at the tops of clouds because they look so very solid from up there. Reading Mellado’s article “Cloud-Top Entrainment in Stratocumulus Clouds,” I learned a lot about what happens at that top boundary layer between clear sky and cloud. As with most topics in the Annual Review of Fluid Mechanics, it’s very complicated and equation heavy. Perhaps the most interesting thing I learned is that what seems like a clear boundary isn’t: “the boundary of a cloud is an elusive concept: Clouds are dilute and disperse suspensions of droplets in moist air, and what looks like a sharp boundary from far away is a transition region scattered with cloud filaments of various sizes and various microphysical properties.” So now on planes I’ll have a completely new series of things to distract me as I stare at clouds.

When I first encountered the article “Vapor Bubbles” by Prosperetti, I was surprised to discover that something I think of as ordinary is actually tremendously complicated:

…geysers, hydrothermal vents, and volcanic eruptions are all phenomena intimately associated with vapor bubbles. The destruction caused by boiling liquid expanding vapor explosions (BLEVEs) is occasionally featured in the media. The phenomenon occurs when a liquid-filled tank is accidentally exposed to fire, which causes the pressure to rise so much that the tank ruptures. A rarefaction wave propagating in the liquid causes rapid vaporization, which results in an even stronger pressure buildup with a violent dispersion of the tank’s contents.

That’s something to remember when watching the fire creep ever closer to the tanker truck in the next blockbuster!

Finally, Stevens & Meneveau’s article “Flow Structure and Turbulence in Wind Farms” gave me a different way of thinking about wind energy. I’m a fan of wind farming in general, but had never given much thought to the ways the turbulent flow coming from the turbine could affect the rest of the turbines. It’s really interesting how it impacts decisions about wind farm layout.

Suzanne K. Moses is Annual Reviews’ Senior Electronic Content Coordinator. For 15+ years, she has played a central role in the publication of Annual Reviews’ online articles. Not a single page is posted online without first being proofed and quality checked by Suzanne.