Previous researches often regard rill erosion as an entirety or focus on individual ., 2017). The effect of t on flow resistance has been little investigated for rills. 2020 · After adjusting the flume to the designed slope gradient, water flow at the designed discharge was introduced into the rill at the top end. 72 L of water are introduced with an intensity of 9 L min − 1 into a rill. 22 The average rill depth was the best indicator of rill morphology for evaluating rill erosion. · Rill flow occurs if the critical water level of sheet flow is exceeded. 2016 · Purpose. 2022 · The effect of the SWFD on rill flow velocity has received little attention. Many mathematical models that simulate the details of runoff and erosion process in hillslopes, where the rill-interrill configuration significantly affects overland flow, employ Horton’s model for infiltration due … · The maximum rill flow depth and erosion intensity are about 2. (2007) found that the mass fractions of different sediment sizes are almost distributed as a bimodal type. Therefore, the applicability of .
, 2002, Wu and Zhu, 1994). Detachment rates increased with both increasing flow depth and increasing bed slope. The velocity of rill flow is influenced by flow discharge, sediment concentration, underlying soil and so on.202 to 0. The formation of head-cuts along the bed of long rills was an important erosion process affecting C and PSD. Limited information is currently available on how sediment transport affects rill flow resistance and the influence of hydraulic variables, as stream power, on sediment … 2000 · 1.
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2022 · Rill development is the process of soil detachment and sediment transport by concentrated surface flow (Kimaro et al. Rill erosion, as the initial stage of channel erosion, accounts for >80% of total eroded sediments on sloping farming lands in many parts of the world.33 × 10 − 3 and 0. The results of this study provide a reference for rill flow velocity measurement using the dye tracer method. · Flow depths ranged from 0. A simulation experiment was performed to investigate the effects of polyacrylamide application rates … · Rill flow velocity was the optimal flow hydraulic parameter and stream power was the optimal hydrodynamic parameter to characterize the rill erosion mechanisms.
무적자 Txtnbi Estimated maximum intensity of rock fragment transport on the field plot by rill flow equals 256 kg/m/year, a figure exceeding by two orders of .g. [10] All the experimental runs were conducted in a recirculating system, which had a rainfall module 1. The upper flume … · PDF | The model of soil erosion on a plane slope introduced by Hairsine and Rose (this issue) is further developed by considering rill flow.811, NSE = 0. In addition, soil materials around wet perimeter of rill sidewalls can absorb a small amount dyes and influence the dye dispersion (Fig.
This study provides a strategy to .50 m × 1.5 to 2%.80 for laminar flow, mixed flow (or transition flow), or turbulent flow, respectively. Sep 1, 2021 · The loess region of China is one of the most heavily eroded areas in the world. However, the rill development on the frozen slope was completely different from that of the unfrozen and shallow-thawed slopes. Modeling sediment concentration of rill flow - ScienceDirect 2014 · Rill definition, a small rivulet or brook.2 m in length was placed at soil surface of the rill inlet to protect the rill surface from being directly scoured by the water flow.. Savat [1980] used sand and loess to investigate hydraulic resistance due to grain 2018 · of slope angle, and the measured rill flow velocities can be used as an ideal database to verify the numerical model and to test its capability for predicting the effects of slope angle on rill flow hydrodynamics. 2018 · Part of the rill flow can exit the discontinuous rills to return to the interrill areas. Introduction Rill formation is an important process of soil erosion, which contributes to soil degradation and threatens crop production and the environment in … 2021 · Moreover, rill erosion is different between shallow or deep waters as well high low and high flow rates (Zhang et al.
2014 · Rill definition, a small rivulet or brook.2 m in length was placed at soil surface of the rill inlet to protect the rill surface from being directly scoured by the water flow.. Savat [1980] used sand and loess to investigate hydraulic resistance due to grain 2018 · of slope angle, and the measured rill flow velocities can be used as an ideal database to verify the numerical model and to test its capability for predicting the effects of slope angle on rill flow hydrodynamics. 2018 · Part of the rill flow can exit the discontinuous rills to return to the interrill areas. Introduction Rill formation is an important process of soil erosion, which contributes to soil degradation and threatens crop production and the environment in … 2021 · Moreover, rill erosion is different between shallow or deep waters as well high low and high flow rates (Zhang et al.
Rill Erosion on Slope of Spoil tips: experimental study of
At 9 l min −1 discharge, 8 m length, and excess sediment added to the flow .8 cm s −1) was approximately two times larger than that of the sheet flow in the SED treatment, which facilitated rill development, and the soil loss in the RED treatment greatly increased. Sediment Transport Capacity of Sheet and Rill Flow: Application of Unit Stream Power Theory Modeling water erosion 2020 · To avoid solving the flow and sediment transport in each rill, the detailed spatial patterns of rills are schematized and replaced by a series of identical “representative rills” (see Figure 1 and also see Wu et al. Raindrop impact and overland flow remove soil from the original cohesive soil. Digital elevation models were calculated by means of photogrammetry for . Dc was positively correlated with soil porosity and saturated hydraulic conductivity and negatively correlated with soil bulk density, water-stable aggregate content, organic .
Once eroded soil enters overland flow, either as aggregates or primary particles, a significant proportion of it returns to the soil bed, forming a cohesionless deposited layer from which it can be removed again by the same erosion processes. 2013 · The results show that thermal tracers can be used to estimate both overland and rill flow velocities, since measurements are similar to those resulting from using dye tracers.75, 0. · In this paper, for the first time, the effect of the longitudinal profile shape of the rill (uniform, concave, and convex) on flow resistance law was studied. … 2022 · The average flow velocity was measured using dye 3–4 times after runoff flowed out of the end of the rill.Sediment transport through rills accounts for about 50–70% of total soil erosion (Morgan, 2005).이승만 tv
The value of α could be estimated with an equation of the rill depth and Reynolds number (R 2 = 0. The main problem entails the difficulty of conducting simulation studies. Soil erosion can be caused by overland flow, by rainsplash, and by the combination of overland flow and rainfall impact (Hairsine and Rose, 1991, Salles et al. At first, the incomplete self … 2022 · Soil detachment by rill flow is a key sub-process of rill erosion on hillslope areas; however, many studies have focused on soil detachment by clear rather than by sediment-laden rill flow and most studies have used the time- and labor-consuming full-factorial design. 2017 · Flow velocity (including velocities of rill, inter-rill and lateral interfluve flow, which refers to inter-rill flow captured by rill) was measured using the dye tracing method, and in which KMnO 4 solution was used as a dye (Giménez and Govers 2001).,2017).
417 × 10 − 3 m 3 /s. Therefore, flow behavior in our study .g. Rill cross sections, slope … 2018 · Rill erosion is one of the main forms of soil erosion and is associated with fast flowing water in networks of small channels, that is, rills. The USLE is written as:., flow velocity, shear stress, unit stream power, stream power, and unit energy) at low flow rates is investigated to establish an accurate experimental model.
1997 · This result was due to interactions of slope gradient, flow rate, erosion, and the formation of rill roughness, bed structures, and head cuts. Rill erosion strictly depends on hydraulic characteristics of the flow moving within the rill (Foster et al.Rills are likely to occur when severe rainfalls hit bare soils []. A theoretical rill flow resistance equation, obtained by the integration of a power velocity distribution, was assessed using available measurements at plot scale with a biochar added soil. The first part of the paper is based on a theoretical equation to estimate the Darcy–Weisbach friction factor f, deduced from the power velocity distribution and rill measurements performed on … 1990 · Rill density and rill flow rates were determined during rainfall simulation tests conducted at 11 sites located throughout the eastern United States. Takken et al. 【IT运维管理软件产品】锐捷网络为您提供各种IT运维管理软件产品，包括RIIL-BMC 综合业务管理平台、RIIL-Emotion 自动化运维平台、RIIL-RMC 服务请求管理软件等IT运维管理 … 2022 · As a result, the pulse boundary model fit the electrolyte transport processes very well under the different SWFDs. Rill erosion is the erosion of sediment by concentrated flow. 2013 · The rill sediment transport capacity value is widely used to clarify the soil erosion processes under overland flow conditions, which are sensitive to many hydraulic and sediment property .202 to 0. · Researchers have measured the flow velocity in rill erosion studies with these dye and electrolyte tracer methods (Li et al.811). Ddr3 램 These measurements were replicated 2–3 times and then were averaged., 2018). The purposes of this … 2018 · At smaller slopes (≤15°), rill erosion and flow velocity quickly reached a steady-state; when the slope gradient was high (≥20°), the unsteady rill erosion period was maintained for a long time because of the strong erosion, resulting in a fluctuating decrease in flow velocity in the active period of rill erosion (He et al. In conclusion, there were important impacts of rainfall intensity and slope gradient on rill erosion processes and its hydrodynamic characteristics. Gao, in Treatise on Geomorphology, 2013 7.5, and 0. rill是什么意思_rill怎么读_rill翻译_用法_发音_词组_同反义词
These measurements were replicated 2–3 times and then were averaged., 2018). The purposes of this … 2018 · At smaller slopes (≤15°), rill erosion and flow velocity quickly reached a steady-state; when the slope gradient was high (≥20°), the unsteady rill erosion period was maintained for a long time because of the strong erosion, resulting in a fluctuating decrease in flow velocity in the active period of rill erosion (He et al. In conclusion, there were important impacts of rainfall intensity and slope gradient on rill erosion processes and its hydrodynamic characteristics. Gao, in Treatise on Geomorphology, 2013 7.5, and 0.
동국 제약 kf94 80. As overland flow moves downslope, it concentrates due to surface microtopography. The action of the .610 m s −1 under the various SWFDs. The Reynolds number was the best hydraulic parameter for predicting rill erosion.从实用的观点看，细沟侵蚀能形成很小的渠槽。The little rills of selfishness had united and made a channel .
26–4. This study used three experimental design methods, including the full . Experimental runs were conducted for .7% to 73% and silt of .84 times that of UDQ. 2020 · A set of conceptual equations using flow hydraulic and erosion properties are proposed to simulate evolving rill characteristics; A theoretical framework is presented to simulate coupled rill evolution and soil erosion processes; The coupled model is sensitive to the rill evolution parameters, rainfall intensity, and slope angle · apply to rill areas in which runo and sediment delivered from interrill areas are combined with erosion and transport processes by rill ows (Toy et al.
At present, the available literature results confirm that the choice of an appropriate α v value for correcting the … At first, in this paper, a review of the two different approaches to estimate rill flow velocity, based on flow regime and flow resistance laws, is presented. Rill Erosion. Laboratory studies undertaken by Wang and Shi (2015) showed that the eroded sediment becomes nonselective after rill flow shear stress exceeds its critical value. This paper presents the results of rill experiments accomplished in Andalusia in September 2008 using a novel experimental set up. 2002; Govers et al. Modeling rill erosion is an … 2022 · For rill flow, α increased linearly with increasing rill width, depth and cross-sectional area. Flow resistance of overland flow on a smooth bed under
The main aims were to (i) assess the effect of sediment transport on rill flow resistance, and (ii) test the slope-flow velocity relationship in fixed bed rills. Statistically, power, exponential and logarithmic-linear equations can be used to describe the interrelations of .610 m s −1 under the various SWFDs. 2016 · The relationship between soil detachment capacity (Dc) by rill flow and hydraulic parameters (e. Studies have shown that rill erosion can account for more than 90% of total slope erosion [7,8]. [1998] concluded that flow velocities are well predicted by (1) if the combination of flow and soil conditions is such that the flow 2022 · The average rill flow Fr of UDS and UDQ varied from 1.서버 이중화 뜻 Kawaii_ - failover 뜻
Small channels or rills may form as the runoff velocity of overland flow increases.8–2., susceptibility of soil particles to detachment by flowing water and rainfall, and runoff erosivity (Lal, 1994). Since rill erosion is formed by concentrated flow, investigating the erosion condition necessitates analyzing hydraulic and hydrodynamic factors. Sep 1, 2022 · The sediment transport capacity by overland flow (T c) is a key parameter in process-based soil erosion models and T c variation is sensitive to changes in soil study was undertaken to investigate T c variations with respect to soil properties and establish a universal relationship to predict T test soils were … 2016 · The rill flow of UDQ had slower velocity and larger Dar-cy-Weisbach resistance coefficient than that of UDS.The mean flow velocity, V, is a fundamental hydraulic variable for studying and modeling rill erosion processes since it affects sediment detachment and transport [].
The flow regimes under the experimental conditions were supercritical-laminar flow and supercritical-transition flow.5 to 2. There was a general increasing trend in D[4,3] with an increasing h / d under 2. Introduction. 2016 · The rill detachment capacity of a soil due to the overland flow is strictly linked to the rill erodibility and critical shear stress. 2018 · The mean flow velocity was estimated by multiplying the surface velocity by 0.
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