Celebrating the physics of all that flows with Nicole Sharp, Ph.D.
- Profile
To Splash or Not to Splash?
Hydrophobic surfaces tend to repel water while hydrophilic ones attract it. This video explores the effects that hydrophobic and hydrophilic surface coatings can have on spheres when dropped in water. There are noticeable differences in splash formation and wake shape. For more, see this research paper.
Vortex Ring Collisions
Gorgeous color schlieren photography reveals the development and interaction of ring vortices. (Photo credit: Rebecca Ing) rebeccaing: It’s Schlier-tastic!! These are my invisible wonders! Gas flows and fluid interactions. Nothing but hot air, metho and acetone, yup, humble old nail polish remover. The images were captured using a colour indicating z-system schlieren optical array, an…
Molecular Diffusion
This video explains molecular diffusion with demonstrations in gases and liquids. Molecular diffusion is an important process in all fluids and will occur in laminar, turbulent, or quiescent fluids. Diffusion occurs more quickly in heated fluids because molecules move more energetically at higher temperatures. (via robertlovespi)
Cornstarch Monsters
[original media no longer available] Shaking a fluid surface often results in standing waves known as Faraday waves, but with a non-Newtonian fluid like oobleck, at some frequencies it’s possible to incite other behaviors. Oobleck is shear-thickening, meaning that its viscosity increases when force is applied. This is what allows it to develop finger-like protrusions…
Colliding Jets
Two fluid jets with diameter 0.85 mm collide, creating a fantastical and unstable fluid structure. Fluid mechanics and art overlap. #
Carboy Combustion
Lighting a thin layer of ethyl alcohol in a jug produces some beautiful pulse jets and a moving wall of flame that shifts and flows according to the changing pressures inside the jug. Like the video’s author, we do NOT recommend trying this combustion demo yourself. As for the video’s questions, firstly, blowing into the…
Shuttlecock Flow Viz
The flow around a shuttlecock is visualized in a water channel using fluorescent dye illuminated by laser light ultraviolet LEDs. Note the recirculation zone on the upper shoulder. Experimenters can match flow characteristics in water to that in air by matching the Reynolds numbers. (Photo credit: Rob Bulmahn) Updated, thanks to information from the photographer.…
Starting Vortices
Whenever a wing stops or starts in a fluid, it produces a vortex. This 2D numerical simulation shows an airfoil repeatedly starting and stopping, shedding a vortex each time. Note how the line of vortices drifts downward in the wake; this is an indication of downwash. (submitted by jessecaps)
Skydiving Indoors
Vertical wind tunnels like this one simulate the experience of skydiving with air speeds up to 270 km/h (168 mph). Here expert freefallers perform a routine similar to synchronized skydiving. By changing the angle and shape of their body with respect to the air flow, they are able to control their lift and drag to…
Reader Question: Similar Blogs?
thegreatfenceof-deactivated2013 asks: Hello! I was wondering if you follow any similar blogs to your awesome blog? I like the idea of learning about awesome mechanical engineering stuff without learning so if you know of anything please help me out. As you might imagine, I started this blog because I didn’t know of any that were doing…