After the origin of the river, the bend that the river will take is very much determined. But the beginning of this turning point happened by chance. It is very complicated to explain how the river bends after its origin. Because the process involves probability. An attempt has been made to explain the matter with fluid dynamics, but there are differing opinions
The strong current of the river erodes the riverbed on both banks of the river. This process of changing river direction is very complex
Once a change in direction begins due to the strong currents and flow forces of the river, the rate of change can be assumed to be very rapid. Soil Erosion occurs on both banks of the river due to this change in the flow of the river. This process of river diversion is very complex and depends on certain special conditions. A very simple explanation of this process is given in physics. The explanation is as follows-
Imge Source
The starting process of bending due to current is quite complex. But once a bend is made, no matter how small, when the river water enters the bend there is a force acting on the flow of water that tends to push the water stream outwards. When riding a swing, you will notice that a ball wants to push you out during the rotation of the swing - something like this. But because of the river banks and the soil around the river, the water cannot go beyond the banks. Because there is a kind of frictional force between the river water and the soil on the banks which prevents the current from pushing out. In this condition, a kind of flow is created in the river, which flows from one bank of the river to the other bank. Call this flow Secondary Flow
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