Livello Segreto

Nicole SharpSalt Fingers <a class="" href="https://fyfluiddynamics.com/wp-content/uploads/DDinsta1.png" rel="nofollow noopener noreferrer" target="_blank"></a> <a class="" href="https://fyfluiddynamics.com/wp-content/uploads/DDinsta2.png" rel="nofollow noopener noreferrer" target="_blank"></a> <a class="" href="https://fyfluiddynamics.com/wp-content/uploads/DDinsta3.png" rel="nofollow noopener noreferrer" target="_blank"></a> Any time a fluid under gravity has areas of differing density, it convects. We’re used to thinking of this in terms of temperature — “hot air rises” — but temperature isn’t the only source of convection. Differences in concentration — like salinity in water — cause convection, too. This video shows a special, more complex case: what happens when there are <a href="https://en.wikipedia.org/wiki/Double_diffusive_convection" rel="nofollow noopener noreferrer" target="_blank">two sources of density gradient</a>, each of which diffuses at a different rate.The classic example of this occurs in the ocean, where colder fresher water meets warmer, saltier water (and vice versa). Cold water tends to sink. So does saltier water. But since temperature and salinity move at different speeds, their competing convection takes on a shape that resembles dancing, finger-like plumes as seen here. (Video and image credit: <a href="https://doi.org/10.1103/APS.DFD.2024.GFM.V2677989" rel="nofollow noopener noreferrer" target="_blank">M. Mohaghar et al.</a>)<a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/2024gofm/" target="_blank">#2024gofm</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/convection/" target="_blank">#convection</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/double-diffusive-convection/" target="_blank">#doubleDiffusiveConvection</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/double-diffusive-instability/" target="_blank">#doubleDiffusiveInstability</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/flow-visualization/" target="_blank">#flowVisualization</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/fluid-dynamics/" target="_blank">#fluidDynamics</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/oceanography/" target="_blank">#oceanography</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/physics/" target="_blank">#physics</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/science/" target="_blank">#science</a>

Nicole SharpVisualizing Unstable Flames <a class="" href="https://fyfluiddynamics.com/wp-content/uploads/thermo_instab1.gif" rel="nofollow noopener noreferrer" target="_blank"></a> <a class="" href="https://fyfluiddynamics.com/wp-content/uploads/thermo_instab2.gif" rel="nofollow noopener noreferrer" target="_blank"></a> <a class="" href="https://fyfluiddynamics.com/wp-content/uploads/thermo_instab3.png" rel="nofollow noopener noreferrer" target="_blank"></a> Inside a combustion chamber, temperature fluctuations can cause sound waves that also disrupt the flow, in turn. This is called a thermoacoustic instability. In this video, researchers explore this process by watching how flames move down a tube. The flame fronts begin in an even curve that flattens out and then develops waves like those on a vibrating pool. Those waves grow bigger and bigger until the flame goes completely turbulent. Visually, it’s mesmerizing. Mathematically, it’s a lovely example of <a href="https://en.wikipedia.org/wiki/Parametric_oscillator" rel="nofollow noopener noreferrer" target="_blank">parametric resonance</a>, where the flame’s instability is fed by system’s natural harmonics. (Video and image credit: <a href="https://doi.org/10.1103/APS.DFD.2024.GFM.V2561866" rel="nofollow noopener noreferrer" target="_blank">J. Delfin et al.</a>; research credit: J. Delfin et al. <a href="https://doi.org/10.1016/j.fuel.2024.132344" rel="nofollow noopener noreferrer" target="_blank">1</a>, <a href="https://doi.org/10.1016/j.proci.2024.105322" rel="nofollow noopener noreferrer" target="_blank">2</a>)<a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/2024gofm/" target="_blank">#2024gofm</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/combustion/" target="_blank">#combustion</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/combustion-instability/" target="_blank">#combustionInstability</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/flame/" target="_blank">#flame</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/flow-visualization/" target="_blank">#flowVisualization</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/fluid-dynamics/" target="_blank">#fluidDynamics</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/instability/" target="_blank">#instability</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/parametric-resonance/" target="_blank">#parametricResonance</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/physics/" target="_blank">#physics</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/resonance/" target="_blank">#resonance</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/science/" target="_blank">#science</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/thermoacoustic-instability/" target="_blank">#thermoacousticInstability</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://fyfluiddynamics.com/tagged/turbulence/" target="_blank">#turbulence</a>

Recent searches

Search options

Administered by:

Server stats:

#2024gofm