Sand detachment under rains with varying angle of incidence

Abstract

In the case of wind-driven rain, as the angle of rain incidence increases, greater force components act parallel to the surface and lower force components act perpendicular to the surface. Therefore, raindrop impact angle could influence the detachment process in the existence of substantial lateral jet development. This could be particularly significant for a cohesionless sand surface that has a weaker resistance to the dislodgement by a raindrop impact than a soil surface. Experiments of simulated wind-driven rain were conducted to evaluate sand detachment rates under increased lateral jetting induced by wind velocities of 6.4, 10.0, and 12.0 m s − 1 at nozzle operating pressures of 75, 100, and 150 kPa and incident on windward and leeward slopes of 4 and 9°. With these set-ups, it was possible to have varying angles of incidence and to determine the effect of the compressive stress and shear stress, evaluated by the horizontal and vertical kinetic energy fluxes (E tx and E tz , respectively), on the detachment rates from the sand surface. At the same vectorwise sum of E tz and E tx , the results showed that there was, for similar values of E tz and E tx in windward slopes, more sand detachment rate; however, for dissimilar values of E tz and E tx in leeward slopes where E tx was significantly higher than E tz , there was less sand detachment rate. Consequently, with certain values of the compressive stress and shear stress, the sand detachment rates under wind-driven rains peaked; and E tz was the limiting component since the rates significantly decreased as E tz particularly decreased in spite of very large values of E tx .

Comparison between sprinkler irrigation and natural rainfall based on droplet diameter

“…Comparing these data with natural rainfall data in windy conditions simulated by Erpul et al (2008), it is found that the energy distribution in this study are close to the data under the condition of working pressure of 100 kPa and 150 kPa, with a 6.4 m/s wind speed. In Erpul's trial, the amounts of sediment formation under the above conditions are very Comparison between sprinkler irrigation and natural rainfall rigation, especially in sandy loam and silt loam.…”

“…[1]-[3] are used to compute SP and its directional components (Erpul et al, 2008): test data for estimating terminal velocity. The most commonly used form is the power function (Atlas & Ulbrich, 1977;Ulbrich, 1983):…”

Granulometric characterization of sediments transported by surface runoff generated by moving storms

“…Soil detachment significantly changes with windward and leeward slopes under wind-driven rains This means that, apart from the transport capacity of the overland flow, the delivery of the detached particles to the flow will be different when the rainfall is upstream-moving from when it is downstream-moving (Erpul, 2003a(Erpul, , 2005(Erpul, , 2008. In fact the experiments do not entirely represent wind-driven rains.…”

Investigating the nonlinear response of soil loss to storm direction using a circular soil flume

“…In some cases comparison has been made for the soil loss associated with these storms (e.g., Erpul et al, 2003Erpul et al, , 2005de Lima et al, 2008;Erpul et al, 2008). Nevertheless, the influence of storm movement on water erosion has received much less attention than has overland flow.…”