#venturi effect

[fuckyeahfluiddynamics]

How Gas Pump Nozzles Work

Ever wonder how a gas pump shuts off when the tank is full? You might guess that there's a sophisticated electronic sensor hidden in there. But there isn't! (Image and video credit: S. Mould)

[fuckyeahfluiddynamics]

When a wedge falls into a pool, it creates a distinctive, doubly-curved splash. Here’s how it works. When the front of the wedge first enters the water, it creates a thin sheet of fluid that gets ejected diagonally upward. As the wedge sinks further, the sheet thickens and ejects at a more vertical angle. That creates a low pressure zone in the air beside the splash, which causes outside air to flow inward, generating a sort of Venturi effect under the splash. Because the outer part of the splash sheet is thinner, it’s more strongly affected by the air flow beneath it, and it gets pulled downward, enhancing the splash’s curvature.

This doubly-curved splash is particular to wedges of the right angle. To see what kind of splashes other shapes make, check out the video below. (Image and video credit: Z. Sakr et al.; for more, see L. Vincent et al.)

[fuckyeahfluiddynamics]

Diving can generate some remarkable splashes. Here researchers explore the splashes from a wedge-shaped impactor. At high speeds, they found that the splash sheet pushed out by the wedge curls back on itself and accelerates sharply downward to “slap” the water surface (top). Studying the air flow around the splash sheet reveals some of the dynamics driving the slap (bottom). The splash sheet quickly develops a kink that grows as the sheet expands. This creates a constriction that accelerates flow on the underside of the sheet. That higher velocity flow means a low pressure inside the constriction, which pulls the thin sheet down rapidly, making it slap the surface. For more, check out the full video. (Image and research credit: T. Xiao et al., source)

[fuckyeahfluiddynamics]

For pedestrians, windy conditions can be uncomfortable or even downright dangerous. And while you might expect the buildings of an urban environment to protect people from the wind, that’s not always the case. The image above shows a simulation of ground-level wind conditions in Venice on a breezy day. While many areas, shown in blue and green, have lower wind speeds, there are a few areas, shown in red, where wind speeds are well above the day’s average. This enhancement often occurs in areas where buildings constrict airflow and funnel it together. The buildings create a form of the Venturi effect, where narrowing passages cause local pressure to drop, driving an increase in wind speed. Architects and urban designers are increasingly turning to numerical simulations and CFD to study these effects in urban environments and to search for ways to mitigate problems and keep pedestrians safe. (Image credits: CFD analysis - SimScale; pedestrians - Saltysalt, skolnv)

This post was sponsored by SimScale, the cloud-based simulation platform. SimScale offers a free Community plan for anyone interested in trying CFD, FEA and thermal simulations in their browser. Sign up for a free account here. 

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[truphysics]

Venturi Effect

Introduction The Venturi effect is a principle in fluid dynamics that describes how fluid speed and pressure change as it flows through a pipe with varying cross-sectional areas. This phenomenon is named after Giovanni Battista Venturi, an Italian physicist. Fundamental Principle The Venturi effect is a direct consequence of the principle of conservation of energy applied to fluid flow,…

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[hunnynectarine]

Why is the air cold when I purse my lips but warm when I keep them open?

[shineetools]

He Totally Sucks

I'm not massively knowledgeable on the physics of pneumatics, but I thought I'd share a rather interesting effect that I come across quite often as a means to safely regulate airflow in industrial equipment.

Enter Giovanni Battista Venturi.

He was an Italian physicist and diplomat who studied fluid mechanics (of which the effect still applies). The effect works so well in the industrial pneumatics equipment I've come across because it allows blockages to occur while still leaving the main compressors to have free airflow and not burning out the motor and also providing suction to other areas of the machine. Although (in some cases) not as efficient, it does allow mechanically simple control of airflow with fail safes.

If one of the spurs of a piece of equipment gets blocked the pressure remains relatively consistent throughout the run. It's a simple principle often overlooked in industrial applications. From fuel injectors to wind instruments, it amazes me the relative simplicity and reliability of the Venturi effect and its many applications.

So today I doff my hat to a great engineer of fluid mechanics. Yours, The Enginer'd

[extremediy]

DIY Paint Booth Exhaust Using the Venturi Effect - Part 2

DIY Paint Booth Exhaust Using the Venturi Effect – Part 2

The paint booth that I converted from an old TV cabinet is complete. I left off with adding and exhaust vent at the top of the cabinet. The next step is to ventilate the cabinet and put in a paint booth exhaust of some kind. I did a bit of research. There were plenty of options available. Box fans, computer fans and squirrel cage fans were just a few of the options I ran into.

I had…

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