Why do vortex happen

Notice the shape of the vortex. Also, notice the flow of the water as it empties into the lower bottle. If you only have one 2-liter bottle, you can still make a vortex by twirling the bottle and holding it over a water basin or the ground to drain, but you will have to refill the bottle each time you use it.

When the water is not rotating, surface tension creates a skin-like layer of water across the small hole in the center of the connector. If the top bottle is full, the water can push out a bulge in this surface to form a bulbous drop, which then drips into the lower bottle.

As water drops into the lower bottle, the pressure in the lower bottle builds until air bubbles are forced into the upper bottle. The pressure that the water exerts on the surface in the connector decreases as the water level in the upper bottle drops. When the water level and pressure drop low enough, the water surface can hold back the water and stop the flow completely.

If you spin the bottles around a few times, the water in the upper bottle starts rotating. As the water drains into the lower bottle, a vortex forms. The water is pulled down and forced toward the drain hole in the center by gravity. If we ignore the small friction forces, the angular momentum of the water stays the same as it moves inward.

This means that the speed of the water around the center increases as it approaches the center of the bottle. This is the same reason that the speed of rotating ice skaters increases when they pull in their arms. To make water move in a circle, forces called centripetal forces must act on the water. You can tell where the centripetal forces are greater by looking at the slope of the water.

Where the water is steeper, such as at the bottom of the vortex, the centripetal force on the water is greater. Water moving with higher speeds and in curves of smaller radius requires larger forces.

The water at the bottom of the vortex is doing just this, and so the wall of the vortex is steepest at the bottom. Think about race cars: Racetracks have steeper banks on high-speed, sharp corners to hold the cars in their circular paths around the track. 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. 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 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. 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. What is Heat? What is Light? What is Magnetism? What is Motion? What is Sound? Donate Volunteer. A Vortex Bottle In the world around us there are many examples of vortices: tornadoes, whirlpools in a sink or tub, swirling vortices in rivers and oceans and, of course, hurricanes. Next invert the second bottle onto the washer and tape them together firmly.

Turn the two bottles over so the full one is on top. Swirl the bottle vigorously to start the water spinning. Set the bottles down and watch the vortex form.