Simulação física de escoamentos superficiais com concentração de pedosedimentos entre 6 e 8%

Physical simulation of overland flow with pedosediment concentration between 6 and 8%

Abstract

Based on previous results of physical experimentation in the laboratory, the objective of this work was to verify whether surface runoff simulations with sediment concentrations of 6 to 8% generate deposits similar to lower (~ 3%) or higher (>14%) flows relative. Two replications of flows exhibited concentrations in these ranges and their mean velocities, Froude and Reynolds numbers, and their deposits were analyzed. A supercritical-turbulent flow regime prevailed between the initial conditions and its arrival in the sedimentation plane, gradually changing to subcritical-laminar flow until it waned. Surface structures of the deposits are similar in layout, but differ in width, preservation of vertical accretion and development of groove marks; as well as in relation to bed microstratigraphy, mainly due to the thickness, organization and number of laminations. The fact that the deposits are formed by more than one lamination shows the effects of the tail/body of the flow in re-settling the materials previously deposited by the head of the flow. Surface structures and bed microstratigraphy coincide with those found in both lower and higher relative concentration flow deposits, meaning that the sediment concentrations of the analyzed flows express the continuum between low density flows and transitional flows between low and high densities.