For the first time, scientists observe ‘hidden roaming’ that affects sand, rocks and snowflakes

Something that looks like ordinary sand, rocks or snow can in fact can hide the rotating streams that move in several directions below the surface.

When the grain moves in the sliding, mostly go down on the highway. This is the “basic flow”, where the particles follow the herd on a large scale. But some grains roam or rotate in hidden patterns, forming “secondary flow”, which affects the extent to which the material journey is.

Understanding how the grain moves below the surface can help explain the medical physics of snow and landslides, and even how we handle everyday materials in wheat or pharmaceutical powder in pharmaceuticals.

However, no one can observe these hidden cycles so far. In a research published in Nature communications Today, we have occupied secondary flow for the first time with our modern X -ray imaging setup.

A bulldozing experience

This idea is not new. Researchers have seen hidden movements in the powerful computer impressions of grain among the rotating cylinders or in land sliding that model the movement of every particle using the basic laws of physics. But this is a complete theoretical method of studying them.

Observing flows in real granular substances – such as sand, snow or so on – has been almost impossible. Looking inside the flow, you have to either stop the grain for standard X -ray scans or add a liquid that will allow it to be seen. Unfortunately, both views change how the grains naturally behave.

We came out to study the flow of glass beads (a perfect granular material for lab setting) in the bulldozing experience, where the conveyor belt pushes the grain into the wall, causing them to pile.

In our lab, we have developed a completely new method called X -ray reography, which can take three -dimensional images of moving cereals. Named Dynamics, this setup allows us to see what is really going below the surface.

Due to our surprise, this test revealed the waves at the surface, which had previously linked the hidden secondary flow.

This flow was never directly observed in three dimensions without stopping any movement or changing the material with fluid.

We can practice these invisible streams practically without disturbing the movement of glass beads. Nevertheless, complex geometry means that we can occupy the expansion of flow in only one direction, as the main direction, along with the conveyor belt, leave the remaining three -dimensional picture incomplete.

Did we discover the bottom

Really to eliminate secondary flow, we went more than just looking at the grains with dinumics.

We developed another X -ray method to make a pile of piles flowing from the X -ray images, under which small waves were linked to the rotating movement. We also measured how the grains move from the deep depths of the pile, including sideways movements.

The main flow goes all in one direction. Therefore, the Side Wes Movement we found was the first direct experimental evidence of secondary flow.

Looking at these invisible flow, we are revealing the amazing capabilities of granular material. They can behave like solid things that support buildings or like complex fluids with complex internal streams.

Rotating movements are normal

Although we have not studied directly land sliding directly, our experiences on bulldozed particles have come to light.

Now we know that whenever the particles are pushed, the secondary flow is in the game, such as when the snow is plowing or running grain in agriculture, for example. The rotating movements we have witnessed appear to be commonplace everywhere in the complex particle flow.

What does this mean for land sliding? Detailed experiences like ours provide important data that can be used to verify and improve mathematical models. Current models often ignore and not predict secondary flow.

Our job offers an experimental basis for future modeling. Understanding and modeling these secondary flows can help engineers better predict the destructive power of land sliding, including runouts that are currently not low.

It can also improve the industrial process from powder handling to powder handling and beyond.

Although our results are specific to bulldozed grains, they point to a wider principle – secondary flow is a basic feature of particle movement that should be considered in any realistic model of granular behavior.

Under the surface of any vibrant pile of grain, the hidden streams are forming a flow. Recognizing these movements is the key to understanding everything from snowfall to industrial particle handling.

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