水中吐氣泡，為啥會變成交替追逐的圓環，水中渦環的原理和應用【萌萌戰隊】

Recently, several netizens have reposted the same video Actor blows bubbles in giant aquarium But spit out two rings of air, one after the other The two rings are chasing as they advance and will be nested alternately So I also spit a few bubbles in the washbasin. But this phenomenon cannot be replicated So we decided to go to the quiet and peaceful Baltic Sea for answers There's an area of ​​shallow water that looks good for experimenting So we slowly dived to the bottom of the sea at a depth of 70 to 80 meters It was found that there was a winding line on the seabed. One meter thick natural gas pipeline And faintly saw a spot of light flickering on the pipe If you look closely, you can see that you don't know who it is on this steel pipe wrapped in concrete TNT explosive and detonator installed Say it's too late, there will be a loud bang Concrete shell and 4cm thick steel pipe inside was blown open Natural gas spews out instantly A big bubble pops up The bubble is rising Due to the impact pressure of the oncoming water flow Being continuously squashed and stretched around The curvature of the edge of the bubble continues to increase The water flow is centrifugally affected when it moves in an arc here Pull the bubble radially to expand At the same time, when the water flows around the edge and meets at the center of the back of the bubble Pressure rise due to impact deceleration leading to a central area before and after the bubble At the same time, it was subjected to a large water pressure and was crushed inward. The gas keeps escaping around to form a ring The water flow on the ring interface at this time will continue to move along the boundary to form a circulation And drive the outer layer of water to rotate together A vortex in the same direction is formed on any section of the bubble ring So this bubble ring is actually a The annular hollow water vortex connected by the head and tail of the vortex tube made by the water flow Known as the vortex ring because the vortex ring is advancing The water in the cross section is also revolving around the vortex tube Causes the water in the outer ring of the ring to retreat downstream The superposition of velocity increases and pressure decreases The water in the inner circle moves against the current Velocity counteracts slower pressure increases That's the Magnus effect The ring is pushed by the radial water pressure difference to continue to expand The gas in the ring is continuously reducing the cross-sectional area to maintain the pressure Therefore, the vortex ring will gradually expand and become thinner as it advances If two vortex rings are lined up in front of each other, the latter vortex ring will enter the forward circulation of the front vortex ring. So pushed forward to accelerate At the same time, the water flow in the outer ring of the rear vortex ring Decelerate and boost pressure due to the reverse movement with the circulation ahead The water flow in the inner circle moves in the same direction as the front circulation to accelerate and decompress is therefore subjected to an inward radial water pressure differential Make the diameter of the ring shrink and expand the section So we see the vortex ring behind Always be driven by the circulation created by the front vortex ring Accelerates forward while shrinking under radial water pressure Drilled through the front vortex ring Not only that, due to the flow velocity of the vortex ring section Gradually increase from outside to inside Causes lower water pressure in the inner ring will be held in place by the pressure of the outer ring At the same time, the pressure difference is perpendicular to the tangential direction of the water flow So that the water flow is only subjected to the centripetal force of the circular motion without being subjected to adverse pressure gradients The rotational kinetic energy can thus be maintained with little loss This causes the vortex ring to rotate for a long time and maintain the ring state According to the characteristics of the vortex ring When we bag a bar Just throw the air-filled plastic bag with the mouth back the air in the middle of the bag is pushed moving around to become an air ring At the same time, the plastic bag inside the ring is relatively backward The plastic bags in the outer ring of the ring are relatively advanced. So the air is rotated by the viscous force also turned into a vortex And also has the ability to maintain shape and rotational kinetic energy Therefore, the air vortex ring can move forward with less attenuation Keep hitting the plastic bag in front Relying on its own kinetic energy to push the plastic bag upside down wrap the object Some netizens asked why the bicycle was covered with a bag Just throw it out for a perfect fit This is actually a smart worker Ingeniously created air vortex ring to push the bag put it on itself