Take a Look at Some of the Most Fascinating Vortex Formations

Kathleen Villaluz

Nature produces a lot of cool and interesting phenomena that often make us wonder how, why, and when do they occur. Take vortices for example. Generally speaking, a vortex is an area in a fluid (air or water) where the flow spins around an axis line and can take a straight or curved shape. It is basically formed when a fluid is stirred or spun. This natural phenomenon can take place on land, air, and water. When vortices are formed, they can complexly move, stretch, twist, and interact with the surrounding fluid. Once a vortex is moving, it carries with it angular and linear momentum, energy, and mass.

We will share with you six types of vortices that have cool visualizations and then let's explore how they are formed and if they pose any engineering problems. Moreover, vortices occur not just on Earth but also in other planetary bodies, and we will give some examples of those too.

Lock Vortex Flow

Despite the technicality of the name, lock vortex flow is an everyday phenomenon where its formation and the way it flows is very easy to understand. In fact, in some cases, this type of vortex is actually an advantage rather than a problem. It's easier to explain lock vortex flow when it's used in a situational example. So, take the pickup truck's tailgate for instance. Some people think it's more fuel efficient to drive with the tailgate down and others believe that it's ideal to drive with the tailgate up. Which one is correct then? Well, first of all, lock vortex flow provides a precise scientific answer to this.

When a pickup truck is driven with the tailgate down, a straight stream of air builds up inside the open perimeter of the pickup. This increases the wind drag on the vehicle and slows it down which means that more work or energy is required to keep the pickup at speed. However, if you drive with the tailgate up, because the open perimeter is now an enclosed space, rotating air bubbles (lock vortex flow) are formed from the oncoming wind flow. The consecutive wind flow, once the lock vortex flow is formed, are deflected off the vehicle and passes through creating only minimal drag. So, driving a pickup truck with the tailgate up is the ideal scenario.

Vortex Shedding

This type of vortex typically causes structural problems as the intensity of the build up of the wind around structures results into failure. When a speeding wind gets into contact with a building's exterior surface, a build up of wind pressure accumulates. Since wind force is a dynamic action, the pressure created at a building's surface also produces vibrations. If the peak wind pressure is high enough, these vibrations can turn into mini earthquakes at certain levels of a structure where the wind direction is passing. This causes a tall building to sway, and if dynamic damping is not provided, the structure could potentially collapse.

Vortex shedding around Heard Island

[Image Source: Wikipedia]

Vortex shedding is an oscillating flow and occurs when air flows past a bluff body. One way of reducing vortex shedding drag is to design a structure to be streamlined so that aerodynamic flow can be achieved. Another way of reducing vortex shedding accumulation on buildings is to introduce surface roughness in the form of architectural aesthetics like balconies and protruding windows. When the flow of wind makes contact with these protruding features, the wind stream is broken down into much smaller wind pressures, which can sometimes be negligible.

Vortex Rings

When an air bubble occupies the core of the vortex a ring-shaped underwater bubble forms. The ring bubble and the surrounding water spins in a poloidal manner as they travel through the water. Just like vibrations, the faster the bubble ring spins, the more stable it travels. As the bubble ring approaches the surface of the water, the bubble's velocity is reduced and the diameter increases.

Bubble Ring in the sunlight

[Image Source: Wikipedia]

One example of how underwater vortex rings are formed is when dolphins or whales blow out bubbles that form into rings when they reach the surface. Smoke rings are another type of vortex or toroidal rings.

Spiral Vortex

The spiral vortex is one of the most typical types of vortices as it can form anywhere, where a speeding wind is present. For example, when an aircraft is landing or taking off, a giant spiral vortex is formed by the passage of an aircraft wing. In the photo below, red powder dust is used to visualize the spiral vortex created by an aircraft.

Aircraft vortex with powder coloring

[Image Source: Wikipedia]

Whirlpools

A whirlpool is an aquatic type of vortex where the meeting of opposing currents produces a swirling cone of water. This is pretty much a large scale version of water being sucked down a bath or sink drain.

A whirlpool can be dangerous for seafarers when the spin of the water becomes powerful. Although there are no official records of large ships being sucked down by a whirlpool, this water vortex is still one to watch out for.

Third largest whirlpool in the world is in Scotland

[Image Source: Wikipedia]

Whirlwinds

One infamous example of a whirlwind is in the form of tornadoes. Tornadoes form when different temperatures of air meet in one spot and start to spin vigorously. The spinning column of air reacts with other high altitude winds, creating a funnel. A cloud consequently forms over the funnel which makes the tornado visible. Although tornadoes can happen all around the world, specific areas produce some of the most notorious tornadoes like the tornado alley and dixie alley in America. Tornadoes are typically destructive and can wipe out a whole city where it passes through.      Tornado near Anadarko, Oklahoma

[Image Source: Wikipedia]

Many other types of vortices exist, each with their own unique way of forming. Some are dangerous, which must be taken into account when designing structures, and some are just natural phenomena that don't require any handling. Vortices also occur in outer space like the Great Red Spot on Jupiter, the Martian dust devils, the North Polar Hexagon of Saturn, and the polar vortices of Venus. Perhaps the scariest type of vortex is in the form of black holes.