Crater formation in soils by raindrop impact

Abstract

The process of crater formation by the impact of water drops on soil, sand and various other target material was studied. Craters of various shapes and sizes were observed on different target materials or conditions, ranging from circumferential depression to completely hemispherical shape. Crater shape was dependent upon target material, its flow stress or shear strength and the presence and thickness of water on the surface. Between 5 and 22 per cent of impact energy was spent on cratering, but the relationship between crater volume and kinetic energy of a raindrop was curvilinear, indicating a lower efficiency of impact energy in removing target material as the energy increases. Impact impulse, on the other hand, showed a more linear relationship with crater volume, and the ratio of impulse over crater volume (I/V) remained constant for the entire range of drop sizes, impact velocities, and surface conditions used in this study. Surface shear strength, represented by the penetration depth of fall-cone penetrometer, appeared to be a key factor involved in this process. An equation was developed which related crater volume to cone penetration depth and impact impulse. Crater volume, which appeared to be a better indicator of the total amount of material dislodged by a raindrop than splash amount, can thus be predicted using this equation.

Integrated Use of GCM, RS, and GIS for the Assessment of Hillslope and Gully Erosion in the Mushi River Sub-Catchment, Northeast China

“…Splash erosion marks the beginning of other types of soil erosion involving raindrop impact, splash of soil particles, and formation of craters [19]. It is called sheet erosion when a thin layer of soil is removed by raindrop impact and shallow surface flow from the whole slope.…”

Experimental investigation into the impact of a liquid droplet onto a granular bed using three-dimensional, time-resolved, particle tracking

“…However, such studies provide limited insight into the additional complexities provided by a liquid projectile, in which deformation and breakup of the droplet, in conjunction with its penetration into the granular medium, has considerable influence on the transfer of energy. The case of a droplet hitting a granular medium has been well documented for the specific case of rain-splash transport in soil-erosion studies, with several papers looking at the process of grain transport [7][8][9] as well as crater formation [10]. Even though this process of splash transport has received considerable attention, little is known about the transfer of momentum between droplets and granular media [9], with only a few recent studies investigating the fundamental interactions involved [9,[11][12][13].…”

Sıçrama Erozyonunun Farklı Kinetik Enerji Akısı ve Farklı Toprak Bünyesi Etkilesimleriyle Arastırılması

“…Yağmur damlasının etkisiyle toprak parçacık-larının parçalanması yağış ile toprak özelliklerine bağlıdır (Ghadiri 2004) ve bununla ilgili olarak deneysel modeller geliştirilmiştir (Al-Durrah ve Bradford 1982, Parsons ve Gadian 2000. Moldenhauer ve Long (1964) yüksek ve düşük şiddetli yağışların toprak kaybına etkisini yapay yağmurlayıcı kullanarak araştırmışlardır.…”