Scientists are still searching for similarities between natural phenomena on Earth and those of Mars, in the hope of a better understanding of the latter. From that was the recent study of sand dune dynamics in Earth’s deserts, and their similarities with those of Mars.
On September 23 of this year, the journal “Geophysical Research Letters” published a study reviewing 5 patterns of crescent sand dune formation, based on extrapolation of the results of 120 laboratory simulation experiments.
Bracken (and alone is Brakhan); They are crescent-shaped sand dunes that appear in different environments, and are formed by the interaction between the unidirectional flow of a fluid such as gas or liquid, and between granular materials such as sand. Where they are formed inside water pipes or on the bottoms of rivers, and take the form of ripples 10 centimeters long, and exceed 100 meters in length in deserts, and more than a kilometer on the surface of Mars.
According to the press release published by the Sao Paulo Research Foundation news website about the study, the time required for these brachins to form varies according to their size as well, as it is estimated at one minute for bracken that form in water, and general for sand dunes. Semicirculars in the desert, and could reach up to a millennium to form giant brachnids on Mars.
According to the statement, researchers from the University of Campinas in the state of Sao Paulo in Brazil conducted 120 experiments on a pair of sand dunes in a hydrodynamic channel made of transparent material, adding turbulent flow of water and observing the interaction of two pairs of crescent sand dunes with a high-resolution camera.
The researchers identified 5 types of bilateral interaction between a pair of sand dunes, one of which was compatible with the course of the water current, and the other was opposite to it. The researchers noted that the five patterns had two main mechanisms, one of which is the turbulence resulting from the flow of the fluid, and the other is the collision between them.
5 Bracken Patterns
And the first type is called a series, and it occurs when the pair of dunes are about the same size. Here, the vortices lead to a decrease in the size of the dune that corresponds to the direction of flow of the water current. Then the two dunes move at the same speed while maintaining a constant distance between them, as if they are in a race between them.
The second type is called fusion, and it occurs when the dune opposite the water current is much smaller than the dune corresponding to the direction of flow, and in this type there is no decrease in the size of the dune corresponding to the flow of the current, and then the two dunes collide and the merging occurs to form a single sand dune.
The third type is the exchange, which occurs when the dune corresponding to the flow of the current is smaller – a small percentage – than the dune opposite the flowing current. And here the collision occurs between them. As it ascends the smaller dune and spreads over the larger barkhan. In this type, erosion of the front of the sand dunes occurs, and new sand dunes are produced that are smaller in size, and they go with the course of the water current with a rapid movement that creates a gap between the sand dunes.
The fourth and fifth types refer to succession or race and segmentation, and it occurs when sand dunes are of different sizes. In this case, the effect of the water eddies on the sand dune, which corresponds to the direction of the current so much that it causes it to split into two smaller parts.
Thus, we have 3 sand dunes with widening gaps between them; Then begins the fifth type of formation, which is retail exchange, which is similar to the third type.
In spite of their difference in size, crescent sand dunes are similar in the mechanism of their formation and interaction, and depending on the laws of size, laboratory simulation experiments can be conducted for these short, centimeter-long water dunes.
And then the results can be transferred to other environments, where the sizes are larger and the time periods are longer, such as those that form on Mars, and thus can understand the formation of crescent sand dunes on the surface of Mars in its past and present and predict its future as well.