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... d levels.</figcaption></figure></div>]]></content:encoded>
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<?xml version="1.0" encoding="UTF-8"?><rss version="2.0" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:sy="http://purl.org/rss/1.0/modules/syndication/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" xmlns:georss="http://www.georss.org/georss" xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#" > <channel> <title>FYFD</title> <atom:link href="https://fyfluiddynamics.com/feed/" rel="self" type="application/rss+xml" /> <link>https://fyfluiddynamics.com</link> <description>Celebrating the physics of all that flows</description> <lastBuildDate>Wed, 13 Mar 2024 17:17:16 +0000</lastBuildDate> <language>en-US</language> <sy:updatePeriod> hourly </sy:updatePeriod> <sy:updateFrequency> 1 </sy:updateFrequency> <generator>https://wordpress.org/?v=6.5.2</generator> <image> <url>https://i0.wp.com/fyfluiddynamics.com/wp-content/uploads/2019/11/FYFD_logo-e1573082043478.png?fit=32%2C32&ssl=1</url> <title>FYFD</title> <link>https://fyfluiddynamics.com</link> <width>32</width> <height>32</height></image> <site xmlns="com-wordpress:feed-additions:1">169405895</site> <item> <title>Reapproaching Supersonic Air Travel</title> <link>https://fyfluiddynamics.com/2024/04/reapproaching-supersonic-air-travel/</link> <comments>https://fyfluiddynamics.com/2024/04/reapproaching-supersonic-air-travel/#respond</comments> <dc:creator><![CDATA[Nicole Sharp]]></dc:creator> <pubDate>Mon, 15 Apr 2024 15:00:00 +0000</pubDate> <category><![CDATA[Phenomena]]></category> <category><![CDATA[aeronautics]]></category> <category><![CDATA[CFD]]></category> <category><![CDATA[computational fluid dynamics]]></category> <category><![CDATA[fluid dynamics]]></category> <category><![CDATA[physics]]></category> <category><![CDATA[science]]></category> <category><![CDATA[shock wave]]></category> <category><![CDATA[sonic boom]]></category> <category><![CDATA[supersonic]]></category> <guid isPermaLink="false">https://fyfluiddynamics.com/?p=21149</guid> <description><![CDATA[Before the Concorde even began regular flights, protests over its sound levels caused the U.S. and many other countries to ban overland commercial supersonic flight. Those restrictions have stood for <a class="read-more" href="https://fyfluiddynamics.com/2024/04/reapproaching-supersonic-air-travel/">Keep reading</a>]]></description> <content:encoded><![CDATA[<p>Before the <a href="https://en.wikipedia.org/wiki/Concorde">Concorde</a> even began regular flights, protests over its sound levels caused the U.S. and many other countries to ban overland commercial supersonic flight. Those restrictions have stood for fifty years. But NASA and Lockheed Martin Aeronautics are hoping to make supersonic air travel a possibility again with their experimental <a href="https://doi.org/10.1063/pt.rzpx.gdmk">X-59 aircraft</a>, designed to have a much quieter sonic boom.</p> <p>In supersonic flight, every curve, bolt, and bump generates a <a href="/tagged/shockwave/">shock wave</a>, and these waves tend to coalesce at the front and back of the aircraft, creating strong leading and trailing shocks. It’s these shock waves that are responsible for the double sonic boom that rattles windows and startles those of us on the ground. The X-59 reduces its noise by spreading out those shock waves, a feat designers managed with heavy reliance on <a href="/tagged/computational-fluid-dynamics/">computational fluid dynamics</a>. They used wind tunnel studies mainly for validation, since iterating designs in the wind tunnel was far slower than working computationally. With the initial aircraft built, the team will now do test flights and, starting in 2026, will fly over the public and solicit feedback on whether the aircraft is acceptably quiet. (Image credit: NASA; via <a href="https://doi.org/10.1063/pt.rzpx.gdmk">Physics Today</a>)</p> <div class="wp-block-image"><figure class="aligncenter size-large"><img fetchpriority="high" decoding="async" width="1024" height="444" src="https://i0.wp.com/fyfluiddynamics.com/wp-content/uploads/20_1_pt.rzpx_.gdmk_.figures.online.f2.png?resize=1024%2C444&ssl=1" alt="The sound of the X-59's sonic boom compared to other familiar sound levels." class="wp-image-21150" srcset="https://i0.wp.com/fyfluiddynamics.com/wp-content/uploads/20_1_pt.rzpx_.gdmk_.figures.online.f2.png?resize=1024%2C444&ssl=1 1024w, https://i0.wp.com/fyfluiddynamics.com/wp-content/uploads/20_1_pt.rzpx_.gdmk_.figures.online.f2.png?resize=300%2C130&ssl=1 300w, https://i0.wp.com/fyfluiddynamics.com/wp-content/uploads/20_1_pt.rzpx_.gdmk_.figures.online.f2.png?resize=768%2C333&ssl=1 768w, https://i0.wp.com/fyfluiddynamics.com/wp-content/uploads/20_1_pt.rzpx_.gdmk_.figures.online.f2.png?resize=1536%2C666&ssl=1 1536w, https://i0.wp.com/fyfluiddynamics.com/wp-content/uploads/20_1_pt.rzpx_.gdmk_.figures.online.f2.png?resize=2048%2C888&ssl=1 2048w, https://i0.wp.com/fyfluiddynamics.com/wp-content/uploads/20_1_pt.rzpx_.gdmk_.figures.online.f2.png?resize=710%2C308&ssl=1 710w" sizes="(max-width: 1024px) 100vw, 1024px" data-recalc-dims="1" /><figcaption class="wp-element-caption">The sound of the X-59’s sonic boom compared to other familiar sound levels.</figcaption></figure></div>]]></content:encoded> <wfw:commentRss>https://fyfluiddynamics.com/2024/04/reapproaching-supersonic-air-travel/feed/</wfw:commentRss> <slash:comments>0</slash:comments> <post-id xmlns="com-wordpress:feed-additions:1">21149</post-id> </item> <item> <title>“Color Show”</title> <link>https://fyfluiddynamics.com/2024/04/color-show/</link> <comments>https://fyfluiddynamics.com/2024/04/color-show/#respond</comments> <dc:creator><![CDATA[Nicole Sharp]]></dc:creator> <pubDate>Fri, 12 Apr 2024 15:00:00 +0000</pubDate> <category><![CDATA[Art]]></category> <category><![CDATA[fluid dynamics]]></category> <category><![CDATA[fluids as art]]></category> <category><![CDATA[marangoni effect]]></category> <category><![CDATA[physics]]></category> <category><![CDATA[science]]></category> <category><![CDATA[surface tension]]></category> <guid isPermaLink="false">https://fyfluiddynamics.com/?p=20665</guid> <description><![CDATA[Brightly colored paints and inks mix and flow in artist Roman De Giuli’s “Color Show.” De Giuli typically creates this fluid art in thin layers atop paper. He’s a master <a class="read-more" href="https://fyfluiddynamics.com/2024/04/color-show/">Keep reading</a>]]></description> <content:encoded><![CDATA[<div class="wp-block-envira-envira-gallery"><div class="envira-gallery-feed-output"><img decoding="async" class="envira-gallery-feed-image" tabindex="0" src="https://i0.wp.com/fyfluiddynamics.com/wp-content/uploads/cs1.png?fit=1024%2C576&ssl=1" title="From "Color Show" by Roman De Giuli." alt="From "Color Show" by Roman De Giuli." /></div></div> <p>Brightly colored paints and inks mix and flow in artist Roman De Giuli’s “Color Show.” De Giuli typically creates this fluid art in thin layers atop paper. He’s a master of the form, manipulating <a href="/tagged/Marangoni-effect/">surface tension gradients</a> to create streaming flows, dendritic patterns, and feathery wisps. If this kind of art is your jam, he offers <a href="https://www.terracollage.com/hdrfluidartwallpaper4k">an app full of live wallpapers</a>* for Android phones. See more of his work on <a href="https://www.terracollage.com">his website</a> and on <a href="https://www.instagram.com/romandegiuli/">Instagram</a>. (Video and image credit: <a href="https://www.terracollage.com">R. De Giuli</a>)<br>*Not sponsored, I just like his art!</p>]]></content:encoded> <wfw:commentRss>https://fyfluiddynamics.com/2024/04/color-show/feed/</wfw:commentRss> <slash:comments>0</slash:comments> <post-id xmlns="com-wordpress:feed-additions:1">20665</post-id> </item> <item> <title>Dendritic Painting Physics</title> <link>https://fyfluiddynamics.com/2024/04/dendritic-painting-physics/</link> <comments>https://fyfluiddynamics.com/2024/04/dendritic-painting-physics/#respond</comments> <dc:creator><![CDATA[Nicole Sharp]]></dc:creator> <pubDate>Thu, 11 Apr 2024 15:00:00 +0000</pubDate> <category><![CDATA[Research]]></category> <category><![CDATA[fluid dynamics]]></category> <category><![CDATA[fluids as art]]></category> <category><![CDATA[instability]]></category> <category><![CDATA[marangoni effect]]></category> <category><![CDATA[non-Newtonian fluids]]></category> <category><![CDATA[physics]]></category> <category><![CDATA[rheology]]></category> <category><![CDATA[science]]></category> <category><![CDATA[shear-thinning]]></category> <category><![CDATA[surface tension]]></category> <category><![CDATA[viscous fingering]]></category> <guid isPermaLink="false">https://fyfluiddynamics.com/?p=21157</guid> <description><![CDATA[In the art of Akiko Nakayama, colors branch and split in a tree-like pattern. In studying the process, researchers found the physics intersected art, soft matter mechanics, and statistical physics. <a class="read-more" href="https://fyfluiddynamics.com/2024/04/dendritic-painting-physics/">Keep reading</a>]]></description> <content:encoded><![CDATA[<p>In the art of Akiko Nakayama, colors branch and split in a tree-like pattern. In studying the process, researchers found the physics intersected art, soft matter mechanics, and statistical physics. In dendritic painting, the process starts with an underlying layer of acrylic paint, diluted with water. Atop this wet layer, you place a drop of acrylic ink mixed with isopropyl alcohol. </p> <p>The combination of both layers is key. The alcohol-acrylic drop on a Newtonian substrate will show spreading, driven by <a href="/tagged/Marangoni-effect/">Marangoni forces</a>, but no branching. It’s the slightly shear-thinning nature of the diluted acrylic paint substrate that allows dendrites to form. As the overlying drop expands, it shears the underlayer, changing its viscosity and allowing the branches to form. You can see <a href="/2022/02/acrylic-paint-fractals/">video of the process here</a>. (Image credit: <a href="https://www.akikopainting.com/">A. Nakayama</a>; research credit: <a href="https://doi.org/10.1093/pnasnexus/pgae059">S. Chan and E. Fried</a>; via <a href="https://physicsworld.com/a/the-physics-behind-fractal-painting-revealed/?utm_campaign=14290-57372&utm_content=Title%3A%20The%20physics%20behind%20%E2%80%98fractal%20painting%E2%80%99%20revealed%20-%20explore%20more&utm_term=&utm_medium=email&utm_source=iop">Physics World</a>) </p>]]></content:encoded> <wfw:commentRss>https://fyfluiddynamics.com/2024/04/dendritic-painting-physics/feed/</wfw:commentRss> <slash:comments>0</slash:comments> <post-id xmlns="com-wordpress:feed-additions:1">21157</post-id> </item> <item> <title>Visualizing Wingtip Vortices</title> <link>https://fyfluiddynamics.com/2024/04/visualizing-wingtip-vortices/</link> <comments>https://fyfluiddynamics.com/2024/04/visualizing-wingtip-vortices/#respond</comments> <dc:creator><![CDATA[Nicole Sharp]]></dc:creator> <pubDate>Wed, 10 Apr 2024 15:00:00 +0000</pubDate> <category><![CDATA[Phenomena]]></category> <category><![CDATA[2023gofm]]></category> <category><![CDATA[flow visualization]]></category> <category><![CDATA[fluid dynamics]]></category> <category><![CDATA[physics]]></category> <category><![CDATA[science]]></category> <category><![CDATA[turbulence]]></category> <category><![CDATA[wingtip vortices]]></category> <guid isPermaLink="false">https://fyfluiddynamics.com/?p=21143</guid> <description><![CDATA[At the ends of an airplane‘s wings, the pressure difference between air on top of the wing and air below it creates a swirling vortex that extends behind the aircraft. <a class="read-more" href="https://fyfluiddynamics.com/2024/04/visualizing-wingtip-vortices/">Keep reading</a>]]></description> <content:encoded><![CDATA[<div class="wp-block-envira-envira-gallery"><div class="envira-gallery-feed-output"><img decoding="async" class="envira-gallery-feed-image" tabindex="0" src="https://i0.wp.com/fyfluiddynamics.com/wp-content/uploads/WT1.png?fit=1024%2C576&ssl=1" title="Wingtip vortices have a big effect on aircraft safety and efficiency." alt="Wingtip vortices have a big effect on aircraft safety and efficiency." /></div></div> <p>At the ends of an <a href="/tagged/airplanes/">airplane</a>‘s wings, the pressure difference between air on top of the wing and air below it creates a swirling vortex that extends behind the aircraft. In this video, researchers recreate this <a href="/tagged/wingtip-vortices/">wingtip vortex</a> in a wind tunnel, <a href="/tagged/flow-visualization/">visualized</a> with laser-illuminated smoke. The team shows the progression from no vortex to a strong, coherent vortex as the flow in the tunnel speeds up. Along the way, there are interesting asides, like the speed where the honeycomb used to smooth the upstream flow is suddenly visibly imprinted on the smoke! (Video and image credit: <a href="https://doi.org/10.1103/APS.DFD.2023.GFM.V0010">M. Couliou et al.</a>)</p>]]></content:encoded> <wfw:commentRss>https://fyfluiddynamics.com/2024/04/visualizing-wingtip-vortices/feed/</wfw:commentRss> <slash:comments>0</slash:comments> <post-id xmlns="com-wordpress:feed-additions:1">21143</post-id> </item> <item> <title>Stomp It Out</title> <link>https://fyfluiddynamics.com/2024/04/stomp-it-out/</link> <comments>https://fyfluiddynamics.com/2024/04/stomp-it-out/#respond</comments> <dc:creator><![CDATA[Nicole Sharp]]></dc:creator> <pubDate>Tue, 09 Apr 2024 15:00:00 +0000</pubDate> <category><![CDATA[Research]]></category> <category><![CDATA[2023gofm]]></category> <category><![CDATA[bouncing]]></category> <category><![CDATA[flow visualization]]></category> <category><![CDATA[fluid dynamics]]></category> <category><![CDATA[physics]]></category> <category><![CDATA[rebound]]></category> <category><![CDATA[science]]></category> <category><![CDATA[swirling]]></category> <guid isPermaLink="false">https://fyfluiddynamics.com/?p=21134</guid> <description><![CDATA[Drop a ball that’s partially filled with water and it may or may not bounce. Why the difference? It all comes down to where the water is before impact. The <a class="read-more" href="https://fyfluiddynamics.com/2024/04/stomp-it-out/">Keep reading</a>]]></description> <content:encoded><![CDATA[<div class="wp-block-envira-envira-gallery"><div class="envira-gallery-feed-output"><img decoding="async" class="envira-gallery-feed-image" tabindex="0" src="https://i0.wp.com/fyfluiddynamics.com/wp-content/uploads/watbounce1.png?fit=1024%2C576&ssl=1" title="Whether a ball partially filled with water bounces on impact depends on the distribution of water before impact." alt="Whether a ball partially filled with water bounces on impact depends on the distribution of water before impact." /></div></div> <p>Drop a ball that’s partially filled with water and it may or may not bounce. Why the difference? It all comes down to where the water is before impact. The more distributed the water is along the walls, the less likely a container will bounce. <a href="http://2023/09/stopping-a-bottles-bounce/">Researchers found</a> they could control the bounce by spinning the bottles before they dropped. Centrifugal force flings the water all over the walls of the spinning bottle, and, when impact happens, the water concentrates into a central jet. For the spinning bottles, that jet is wide, messy, and swirling; it breaks up quickly, expending energy that could otherwise go into a bounce. In effect, the spinning bottle’s jet forms quickly enough to “stomp” the rebound. (Video and image credit: <a href="https://doi.org/10.1103/APS.DFD.2023.GFM.V0027">A. Martinez et al.</a>; research credit: <a href="https://doi.org/10.1103/PhysRevLett.130.244001">K. Andrade et al.</a>)</p>]]></content:encoded> <wfw:commentRss>https://fyfluiddynamics.com/2024/04/stomp-it-out/feed/</wfw:commentRss> <slash:comments>0</slash:comments> <post-id xmlns="com-wordpress:feed-additions:1">21134</post-id> </item> <item> <title>“Mason Bee at Work”</title> <link>https://fyfluiddynamics.com/2024/04/mason-bee-at-work/</link> <comments>https://fyfluiddynamics.com/2024/04/mason-bee-at-work/#respond</comments> <dc:creator><![CDATA[Nicole Sharp]]></dc:creator> <pubDate>Mon, 08 Apr 2024 15:00:00 +0000</pubDate> <category><![CDATA[Phenomena]]></category> <category><![CDATA[aerodynamics]]></category> <category><![CDATA[bees]]></category> <category><![CDATA[biology]]></category> <category><![CDATA[flapping flight]]></category> <category><![CDATA[fluid dynamics]]></category> <category><![CDATA[physics]]></category> <category><![CDATA[science]]></category> <guid isPermaLink="false">https://fyfluiddynamics.com/?p=20895</guid> <description><![CDATA[Mason bees like this one build landmarks to help them navigate as they construct a shelter for their eggs. Even hauling materials, these bees can easily stay aloft. This is <a class="read-more" href="https://fyfluiddynamics.com/2024/04/mason-bee-at-work/">Keep reading</a>]]></description> <content:encoded><![CDATA[<p>Mason <a href="/tagged/bees/">bees</a> like this one build landmarks to help them navigate as they construct a shelter for their eggs. Even hauling materials, these bees can easily stay aloft. This is in contrast to an old misconception that physics can’t explain how a bee flies. It’s true that bees don’t fly using the same mechanisms as a typical airplane — no fixed wings here! But they, like every other flyer aerodynamicists study, still produce <a href="/tagged/lift-generation/">lift</a> and <a href="/tagged/drag/">drag</a> and thrust. The <a href="/tagged/flapping-flight/">flapping</a> of a bee’s wings generates much unsteadier quantities of these things, but at its small size, that is no hindrance to its ability to control its flight and even carry cargo. (Image credit: S. Zankl; via <a href="https://www.nhm.ac.uk/wpy/gallery/2023-mason-bee-at-work?tags=ed.current">Wildlife POTY</a>)</p>]]></content:encoded> <wfw:commentRss>https://fyfluiddynamics.com/2024/04/mason-bee-at-work/feed/</wfw:commentRss> <slash:comments>0</slash:comments> <post-id xmlns="com-wordpress:feed-additions:1">20895</post-id> </item> <item> <title>“Nimbus”</title> <link>https://fyfluiddynamics.com/2024/04/nimbus/</link> <comments>https://fyfluiddynamics.com/2024/04/nimbus/#respond</comments> <dc:creator><![CDATA[Nicole Sharp]]></dc:creator> <pubDate>Fri, 05 Apr 2024 15:00:00 +0000</pubDate> <category><![CDATA[Art]]></category> <category><![CDATA[cloud formation]]></category> <category><![CDATA[clouds]]></category> <category><![CDATA[fluid dynamics]]></category> <category><![CDATA[fluids as art]]></category> <category><![CDATA[physics]]></category> <category><![CDATA[science]]></category> <category><![CDATA[turbulence]]></category> <guid isPermaLink="false">https://fyfluiddynamics.com/?p=20485</guid> <description><![CDATA[Ephemeral clouds drift through unusual places in artist Berndnaut Smilde‘s works. He creates his clouds from smoke and water, launching them for a matter of seconds before they dissipate. During <a class="read-more" href="https://fyfluiddynamics.com/2024/04/nimbus/">Keep reading</a>]]></description> <content:encoded><![CDATA[<div class="wp-block-envira-envira-gallery"><div class="envira-gallery-feed-output"><img decoding="async" class="envira-gallery-feed-image" tabindex="0" src="https://i0.wp.com/fyfluiddynamics.com/wp-content/uploads/smilde-1.jpg?fit=1024%2C773&ssl=1" title="“Nimbus De.Groen” (2017). Photo by Cassander Eeftinck Schattenkerk" alt="“Nimbus De.Groen” (2017). Photo by Cassander Eeftinck Schattenkerk" /></div></div> <p>Ephemeral <a href="/tagged/cloud-formation/">clouds</a> drift through unusual places in artist <a href="https://www.berndnaut.nl/">Berndnaut Smilde</a>‘s works. He creates his clouds from smoke and water, launching them for a matter of seconds before they dissipate. During that time, he and his collaborators take photographs of the clouds, creating a memento of a time already past. Catch more of Smilde’s short-lived weather on his <a href="https://www.berndnaut.nl/">website</a> and <a href="https://www.instagram.com/berndnaut/">Instagram</a>. (Image credit: <a href="https://www.berndnaut.nl/category/works/">B. Smilde</a> and collaborators; via <a href="https://www.thisiscolossal.com/2023/11/berndnaut-smilde-nimbus-clouds/">Colossal</a>)</p>]]></content:encoded> <wfw:commentRss>https://fyfluiddynamics.com/2024/04/nimbus/feed/</wfw:commentRss> <slash:comments>0</slash:comments> <post-id xmlns="com-wordpress:feed-additions:1">20485</post-id> </item> <item> <title>Simeis 147</title> <link>https://fyfluiddynamics.com/2024/04/simeis-147/</link> <comments>https://fyfluiddynamics.com/2024/04/simeis-147/#comments</comments> <dc:creator><![CDATA[Nicole Sharp]]></dc:creator> <pubDate>Thu, 04 Apr 2024 15:00:00 +0000</pubDate> <category><![CDATA[Phenomena]]></category> <category><![CDATA[astrophysics]]></category> <category><![CDATA[fluid dynamics]]></category> <category><![CDATA[instability]]></category> <category><![CDATA[physics]]></category> <category><![CDATA[science]]></category> <category><![CDATA[shockwave]]></category> <category><![CDATA[stellar evolution]]></category> <category><![CDATA[supernova]]></category> <category><![CDATA[turbulence]]></category> <guid isPermaLink="false">https://fyfluiddynamics.com/?p=21088</guid> <description><![CDATA[Sometimes known as the Spaghetti Nebula, Simeis 147 is the remnant of a supernova that occurred 40,000 years ago. The glowing filaments of this composite image show hydrogen and oxygen <a class="read-more" href="https://fyfluiddynamics.com/2024/04/simeis-147/">Keep reading</a>]]></description> <content:encoded><![CDATA[<p>Sometimes known as the Spaghetti Nebula, Simeis 147 is the remnant of a <a href="/tagged/supernova/">supernova</a> that occurred 40,000 years ago. The glowing filaments of this composite image show hydrogen and oxygen in red and blue, respectively. These are the outlines of the <a href="/tagged/shockwave/">shock waves</a> that blew off the outer layers of the one-time star within. What remains of that star’s core is now a pulsar, a fast-spinning neutron star with a solar wind that continues to push on the dust and gas we see here. (Image credit: <a href="https://www.facebook.com/stephane.vetter.nuitsacrees">S. Vetter</a>; via <a href="https://apod.nasa.gov/apod/ap240227.html">APOD</a>)</p>]]></content:encoded> <wfw:commentRss>https://fyfluiddynamics.com/2024/04/simeis-147/feed/</wfw:commentRss> <slash:comments>2</slash:comments> <post-id xmlns="com-wordpress:feed-additions:1">21088</post-id> </item> <item> <title>Light Pillars</title> <link>https://fyfluiddynamics.com/2024/04/light-pillars/</link> <comments>https://fyfluiddynamics.com/2024/04/light-pillars/#respond</comments> <dc:creator><![CDATA[Nicole Sharp]]></dc:creator> <pubDate>Wed, 03 Apr 2024 15:00:00 +0000</pubDate> <category><![CDATA[Phenomena]]></category> <category><![CDATA[fluid dynamics]]></category> <category><![CDATA[ice]]></category> <category><![CDATA[meteorology]]></category> <category><![CDATA[physics]]></category> <category><![CDATA[science]]></category> <category><![CDATA[weather]]></category> <guid isPermaLink="false">https://fyfluiddynamics.com/?p=21112</guid> <description><![CDATA[These lovely pillars of light over the Mongolian grasslands are the result of tiny, suspended ice crystals. With the right weather conditions, ice crystals can align so that their largest <a class="read-more" href="https://fyfluiddynamics.com/2024/04/light-pillars/">Keep reading</a>]]></description> <content:encoded><![CDATA[<p>These lovely <a href="https://atoptics.co.uk/blog/light-pillars/">pillars of light</a> over the Mongolian grasslands are the result of tiny, suspended ice crystals. With the right weather conditions, ice crystals can align so that their largest faces are roughly parallel to the ground. In this orientation, the crystals collect and reflect artificial lights from the ground into these towering light pillars. It’s worth noting that the pillars aren’t located directly above the light source; instead, the column of crystals will lie roughly halfway between the light source and the observer. Next time you’re out on a cold winter night, see if you can find one! (Image credit: N. D. Liao; via <a href="https://apod.nasa.gov/apod/astropix.html">APOD</a>)</p>]]></content:encoded> <wfw:commentRss>https://fyfluiddynamics.com/2024/04/light-pillars/feed/</wfw:commentRss> <slash:comments>0</slash:comments> <post-id xmlns="com-wordpress:feed-additions:1">21112</post-id> </item> <item> <title>Lasers and Soap Films</title> <link>https://fyfluiddynamics.com/2024/04/lasers-and-soap-films/</link> <comments>https://fyfluiddynamics.com/2024/04/lasers-and-soap-films/#respond</comments> <dc:creator><![CDATA[Nicole Sharp]]></dc:creator> <pubDate>Tue, 02 Apr 2024 15:00:00 +0000</pubDate> <category><![CDATA[Research]]></category> <category><![CDATA[elasticity]]></category> <category><![CDATA[flow visualization]]></category> <category><![CDATA[fluid dynamics]]></category> <category><![CDATA[laser]]></category> <category><![CDATA[marangoni effect]]></category> <category><![CDATA[physics]]></category> <category><![CDATA[science]]></category> <category><![CDATA[shockwave]]></category> <category><![CDATA[soap film]]></category> <category><![CDATA[surface tension]]></category> <category><![CDATA[surfactant]]></category> <guid isPermaLink="false">https://fyfluiddynamics.com/?p=21073</guid> <description><![CDATA[Soap films are a great system for visualizing fluid flows. Researchers use them to look at flags, fish schooling and drafting, and even wind turbines. In this work, researchers explore <a class="read-more" href="https://fyfluiddynamics.com/2024/04/lasers-and-soap-films/">Keep reading</a>]]></description> <content:encoded><![CDATA[<p><a href="/tagged/soap-film/">Soap films</a> are a great system for visualizing fluid flows. Researchers use them to look at <a href="/2020/09/flexible-filament-reduces-drag/">flags</a>, <a href="/2017/07/in-sports-flocks-of-birds-and-schools-of-fish/">fish schooling</a> and drafting, and even <a href="/2014/12/vertical-axis-wind-turbines-vawt-are-an/">wind turbines</a>. In <a href="https://doi.org/10.1103/PhysRevFluids.9.L022001">this work</a>, researchers explore the soap film’s reaction to lasers. When surfactant concentrations in the soap film are low, laser pulses create <a href="/tagged/shockwave/">shock waves</a> (above) in the film that resemble those seen in aerodynamics. The laser raises the temperature at its point of impact, lowering the local surface tension. That temperature difference triggers a <a href="/tagged/Marangoni-effect/">Marangoni flow</a> that draws the heated fluid outward. The low surfactant concentration gives the soap film relatively high elasticity, and that allows the shock waves to form.</p> <p>In contrast, a soap film with a high concentration of surfactants has relatively little elasticity. In these films (below), the laser creates a mark that stays visible on the flowing soap film. This “engraving” technique could be used to visualize flow in the soap film without using tracer particles. (Image and research credit: <a href="https://doi.org/10.1103/PhysRevFluids.9.L022001">Y. Zhao and H. Xu</a>)</p> <div class="wp-block-image"><figure class="aligncenter size-full"><img decoding="async" width="509" height="720" src="https://i0.wp.com/fyfluiddynamics.com/wp-content/uploads/laser_soap.gif?resize=509%2C720&ssl=1" alt="When surfactant concentrations are high, a laser pulse "engraves" spots onto a flowing soap film. Shown in terms of interference (left) and Schlieren (right) imaging." class="wp-image-21074" data-recalc-dims="1"/><figcaption class="wp-element-caption">When surfactant concentrations are high, a laser pulse “engraves” spots onto a flowing soap film. Shown in terms of interference (left) and Schlieren (right) imaging.</figcaption></figure></div>]]></content:encoded> <wfw:commentRss>https://fyfluiddynamics.com/2024/04/lasers-and-soap-films/feed/</wfw:commentRss> <slash:comments>0</slash:comments> <post-id xmlns="com-wordpress:feed-additions:1">21073</post-id> </item> </channel></rss> If you would like to create a banner that links to this page (i.e. this validation result), do the following:
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