Akademik Veri Yönetim Sistemi
Geomorphology, cilt.104, sa.3-4, ss.191-202, 2009 (SCI-Expanded)
Wind tunnel experiments for 'Raindrop Detachment and Wind-Driven Transport' (RD-WDT) process were conducted under improved lateral jetting induced by wind velocities of 6.4, 10, and 12 m s- 1 at nozzle operating pressures of 75, 100, and 150 kPa. Wind-driven rainfalls were also incident on the windward and leeward slopes of 4° and 9° to have a broad variation in the angle of incidence. The objective of this experimental set-up was to distinguish the roles of both impact components of obliquely striking wind-driven raindrops on RD and wind on WDT. Raindrop impact components and reference horizontal wind were quantified by normal (Etz) and horizontal (Etx) kinetic energy fluxes and wind shear velocity (u*), respectively, to physically model the process of RD-WDT. The results showed, at each level of u*, differential sand transport rates by RD-WDT (qm(RD-WDT)) occurred depending on the magnitude of raindrop impact components, and qm(RD-WDT) increased as the relative contribution of Etz increased. Although Etx was more correlated with qm(RD-WDT) than Etz, the extreme increases in Etx at the expense of Etz brought about no increases but decreases in qm(RD-WDT). An RD-WDT model was built under the process of examining the discrete effects of Etz and Etx on RD together with u* and resulted in a better coefficient of determination (R2 = 0.89) than only total kinetic energy (Et) did alone with u* (R2 = 0.84). In this study, Etx was strongly related to u* and not to Etz, which was the principal difference from the previous rainsplash studies, which relied on the compensatory lateral jet development by the compressive pressure build-up at the raindrop-soil interface. Including Etx in the RD-WDT model both separated the distinct role of each raindrop impact component in RD and improved the performance of u* in WDT by better distinguishing its interaction with Etx, which was not explicitly separated in previous models of RD-WDT. © 2008 Elsevier B.V. All rights reserved.