The friction factor is affected by variations of fluid physical properties caused by variations in temperature and by the action of buoyancy forces. In rough channels the hydraulic resistance increases due to formation of vortices at the roughness elements leading to additional loss of flow specific energy. Three types of roughness can be distinguished: Natural roughness, which is formed as a result of long operation of pipelines.
Erosion by Glaciers. Like flowing water, flowing ice erodes the land and deposits the material elsewhere. Glaciers cause erosion in two main ways: plucking and abrasion. Both are illustrated at this link: [Insert a link to an animation showing how glaciers cause erosion by plucking and erosion.] Plucking is the process by which rocks and other sediments are picked up by a glacier.
That made him smile. Dad said, 'There are several agents of erosion that occur. Water can be one of the most effective and efficient modes of erosion. Waves, for instance, can cause changes in landforms by weathering the surrounding rocks and forming a beach by eroding the debris and depositing it on the shore. As the waves slowly wear down the rocks, the bits of rock turn into sand, which is a size of a rock piece.