Splash Effect Research Articles

A fast water-slide layout approach using smooth surfaces, Saint Venant’s stationary water streamline, and passenger sliding interaction – theory, implementation, and validation

Water-slide manufacturers are constantly searching for innovative designs that maximize the rider’s fun while complying with safety requirements. However, the current state-of-the-art does not offer any simulation tool capable of aiding the design phase before manufacture in an affordable computational time. In this paper, we present a novel approach using smooth surface models together with Saint Venant’s filament theory to predict the water channel and, by this, a realistic estimation of passenger/water-slide interaction. The paper covers the theory and the experimental validation for the case of circular slide cross-sections. It is shown that the predicted water channel follows very well the measurement even without the influence of Saint Venant’s water-height terms and of the elliptical correction of the water cross-section for slanted water streamlines with respect to the centerline of the circular tube. Thus, for this kind of applications, a simple Bernoulli streamline model with proper water-slide friction parameters is shown to be sufficient. On the other hand, parameter identification of fluid-surface friction shows that three terms must be considered: a static one, a curvature-dependent correction, and a third correction factor for changes from low to large curvature (splashing effect). The results are also compared with fluid simulations using OpenFOAM. It is shown that the results of the simple model are not less accurate than the fluid-dynamics model, while needing only 1/100.000 of the computational time. The paper shows also the passenger/slide interaction by a multibody model including contact and passenger/fluid interactions. It is shown that the interaction between the passenger and water is significant for correct reproduction of real motion, showing that the water channel is relevant for computer-based water-slide layouts. As the water-channel parameters can be sufficiently modeled by Bernoulli’s streamline theory, the approach is independent of the slide cross-section and thus extendable to general cases. Also, as the computations run at 7/10 of real time, they can be used for online optimizations and passenger-specific actions on site.

Oil film deposition characteristics and judgment of lubrication effect of splash lubricated gears

Oil film deposition characteristics and judgment of lubrication effect of splash lubricated gears

In-pipe hydropower vertical axis parallel turbines prototype: performance and workability testing

ABSTRACT An improvised version of a vertical axis twin turbine in-pipe hydropower prototype, with bigger power generation (PG) channels and turbines as compared to the previous one was developed and designated as P40. The P40 was fabricated mainly using mild steel. This study aims to evaluate the flow properties, power generation performance, and workability of the P40. At the maximum flow rate of 0.076 m3/s, each of the PG channels at both sides of the P40 allowed about 13% of the water to flow through them and the P40 absorbed 34.4% of the 1.25 bar stagnation pressure of the flow. Both turbines showed almost identical performance, generating a total mechanical power up to 0.608 kW at the maximum flow rate. Overall, a turbine efficiency of more than 70% was obtained at respective flow rate conditions and the highest was 84.7%. All the valves at the inlets and outlets of the PG channels functioned perfectly not to let water flow through them to allow for maintenance work of the turbines’ system when necessary. Overall, the P40 performed effectively as a device that allowed most water to flow uninterruptedly, while simultaneously generating power. Based on the water splash effect in the turbine casing, further study is recommended to increase turbine efficiency by improvising the prototype design.

Study on the Effect of Two Angle and Two Flow Oxygen Lance Jet on Molten Pool in Converter

To achieve the smelting effect of low splash in large and medium-sized converters, the jet flow field simulated by compressed air at room temperature is studied by the oxygen lance (OL) jet detection experimental system in this paper. This paper mainly analyzes the variation law of jet velocity at the geometric axis of the OL nozzle and scalar distribution and attenuation of jet isovelocity line at different cross sections. The results show that the oxygen jet cross-section of all OL nozzles gradually expands with the rise of OL position. When the large hole flow ratio is between 55% and 65%, the large hole angle is between 12° and 14° and the small hole angle is between 16° and 18°, therefore the angle of hole plays a significant role in the impact radius. The larger the angle is, the larger the impact radius is. The area of action between jet and molten pool could be enlarged by staggered double-structure six-hole OL.

Sprayability Analysis of Pristine and Enhanced PEDOT:PSS Inks via Electrohydrodynamic Spray Deposition

Poly (3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT:PSS) is a conductive polymer and versatile material to fabricate numerous organic electronic devices. PEDOT:PSS inks were studied and analyzed for their sprayability via Electrohydrodynamic (EHD) printing. Commercially obtained pristine PEDOT:PSS ink could not produce any decent cone-jet mode due to its high surface tension and viscosity. Two different surfactants – acetone and ethanol were then dispersed into PEDOT:PSS at different concentrations to enhance the sprayability of the PEDOT:PSS ink. Both modified PEDOT:PSS inks could produce a cone-jet mode of spraying, which is essential for EHD printing. The flow rates were tested between 10 - 20 μl/hr. These limits were established to prevent the splashing effect at a higher flow rate (>20μl/hr) and inks disintegrating at a lower flow rate 5μl/hr. PEDOT:PSS:Acetone and PEDOT:PSS:Ethanol with 50:50 and 75:25 ratios, respectively, produced the best performance in their respective categories.

Structural and magnetic properties comparison between cobalt ferrite films obtained by different deposit method

We presented a comparison of the structural, morphological, and magnetic properties between films of cobalt ferrite oxide (CFO), these were deposited with pulsed laser deposition (PLD) and spin-coating (SC) technique. In CFO films obtained by PLD method, a preferential orientation is clearly observed in (004) planes, with a large grain size distribution associated with the splashing effect. For the CFO films obtained by SC method have a homogeneous microstructural distribution with grain size around 50 nm. Additionally, Raman spectra deconvolution was used to estimate the cation distribution in CFO films. Magnetic measurement of CFO films obtained by SC shows a coercive field increment, and which that can be due to a reinforcement in magnetocrystalline anisotropy due to the homogeneous microstructure, whereas for CFO films obtained by PLD, it shows a coercive field decrement due to the splashing effect.

Comprehensive evaluation of throughfall erosion in the banana plantation

AbstractBanana is an important cash crop in tropical and subtropical areas; however, the development of banana farming has caused thorny ecological problems, such as water and soil loss. There are few studies on the runoff response to rainfall in banana land to date. In this study, several evaluation indexes, rainfall redistribution, throughfall erosivity, splash kinetic energy, soil splash loss and runoff, respectively, were used to clarify the mechanism of soil erosion in banana land. Results showed that the atmospheric rainfall was significantly redistributed by the banana canopy, with about 81.2% throughfall, 8.3% stemflow and the rest canopy interception. Although the throughfall erosivity evaluated by the model was slightly lower than that of open rainfall, the throughfall kinetic energy and the soil particle splash loss reached 1.5 times and 5 times higher than that of open rainfall, respectively. Consequently, throughfall has an obvious splash erosion effect on the surface soil. In addition, influenced by throughfall and stemflow, surface runoff during the rainy season (May–September) accounts for the annual 91.7%, July and August in particular having the highest incidence of soil erosion in banana land. The above results suggest that the convergence effect of the banana canopy on rainwater is the main inducement for the increase in throughfall volume and surface runoff volume. Therefore, it is necessary to implement soil and water conservation measures on banana fields during the rainy season, such as planting low vegetation under the banana canopy to mitigate splash effects.

Aerodynamic performance investigation of an axial flow compressor under water ingestion

This paper presents numerical simulations of the effects of water ingestion in the axial flow compressor. A self-compiled droplet-wall interaction model is used to study the impingement of the droplets and the film fragmenting process on the surfaces of the compressor blades, which also included the splashing effects. The blade profile has been divided into small regions to effectively apply the rough wall model to capture the film-related flow losses, which has shown flow characteristics with better accuracy. The formation of water film, its shedding, the size, and the movement of droplets after film peeling have been investigated using unsteady simulations at different time intervals. The increased loss of characteristics, shortening of the operating range, and change of flow velocity angle were observed with increasing water content. Moreover, the current research work shown that an increase in the amount of water has severe aerodynamic effects that caused the shock waves to move an upstream location with an increase in intensity. A higher blockage is generated in the tip section flow as the amount of the water increased. Tip losses were very dominant as water injection rate increased, resulting an additional energy loss and performance degradation.

Numerical Simulation and Experimental Study of the Drop Impact for a Multiphase System Formed by Two Immiscible Fluids.

The multiphase splash phenomenon is especially interesting in the context of environmental protection, as it could be a mechanism for transporting various types of pollution. A numerical 3D multiphase transport model was applied to a splash that occurred under the impact of a petrol drop on the water surface. The splash phenomenon in immiscible liquids was simulated using the multiphaseInterFoam solver, i.e., a part of the OpenFOAM computational fluid dynamics software implementing the finite volume method (FVM) for space discretization. Thirteen variants with a variable drop size (3.00–3.60 mm) or drop velocity (3.29–3.44 m/s) were conducted and validated experimentally based on splash images taken by a high-speed camera (2800 fps). Based on the numerical simulation, it was possible to analyse aspects that were difficult or impossible to achieve experimentally due to the limitations of the image analysis method. The aspects included the cavity spread, the jet forming moment, and, notably, the scale of the petroleum contamination spread in the splash effect. The simulations showed that droplets detaching from the crown did not consist of pure water but were mostly a “mixture” of water and petrol or petrol alone. The applied modelling workflow is an efficient way to simulate three-phase splash phenomena.

Computational Modeling of Nasal Drug Delivery Using Different Intranasal Corticosteroid Sprays for the Treatment of Eustachian Tube Dysfunction.

Eustachian tube dysfunction (ETD) is a common otolaryngologic condition associated with decreased quality of life. The first-line treatment of ETD is intranasal corticosteroid sprays (INCS). Computational fluid dynamics (CFD) was used to study particle deposition on the Eustachian tube (ET) using two commercial INCS (Flonase and Sensimist). Simulations also considered the effects of nostril side, insertion depth, insertion angle, cone spray angle, inhaling rates, wall impingement treatment, and fluid film. Flonase and Sensimist produced different particle size distributions and sizes. Sensimist droplets are smaller, less sensitive to asymmetry in nostrils anatomy and variation in insertion angle, and therefore can reach the posterior nasopharynx more readily. Flonase produces larger particles with greater inertia. Its particles deposition is more sensitive to intrasubject variation in nasal anatomy and insertion angles. The particle deposition on the ET was sensitive to the wall impingement model. The deposition on the ET was insignificant with adherence only <0.15% but increased up to 1-4% when including additional outcomes rebound and splash effects when droplets impact with the wall. The dose redistribution with the fluid film is significant but plays a secondary effect on the ET deposition. Flonase aligned parallel with the hard palate produced 4% deposition efficiency on the ET, but this decreased <0.14% at the higher insertion angle. INCS with larger droplet sizes with a small insertion angle may be more effective at targeting droplet deposition on the ET opening.

Analysis of “Crazy Aesthetics" of Painting in Ming Dynasty

After the long-term ethnic confrontation and the havoc that occurred during the Southern Song, Liao, Jin, Xia, Mongolian, and Yuan Dynasties, the rulers of the early Ming Dynasty once devoted themselves to the revival of the long-decayed Royal Academy of Painting and intended to reproduce the grand occasion of the former academy-style painting, to enjoy being the royal family. For a period of time, the painting in the early Ming Dynasty was shrouded in the retro style of academy style painting. From the perspective of region and time, the academy-style painting system represented by Liu, Li, Ma, and Xia in the Southern Song Dynasty was undoubtedly the most easily accepted and learned painting style from the psychological and cognitive levels of painters in the early Ming Dynasty. However, from the mid-Ming Dynasty, the painting style of the Zhejiang school gradually became wild, and its painters often regarded themselves as "immortal drunk", and their brush and ink language were indulgent and unruly, like a golden snake dancing wildly. Pursue the ink splash effect mixed with ink and wash, and even show the sense of power and speed of sweeping and swaying freely like a performance in front of people. And its form also began to be rude and frugal, resulting in the slander of "mad monster" and "crazy evil school". The "madness" of the painters during this period was not an accidental case, but an artistic phenomenon that was precisely opposed to the Wumen literati painting school that began to occupy the mainstream of the painting circle in the middle of the Ming Dynasty. The artistic pursuit and the aesthetic tendency of the orthodox social mainstream thinking. Under the unprecedented strengthening of centralization during the Ming Dynasty and the ideological control of the eight-legged scholars, the art world was full of "madness". This phenomenon makes people think about the two-way interaction between the times and art, and whether mainstream art can reflect mainstream consciousness. form? Between "cult" and "orthodox", who can better express the demands of an era? I hope to have a preliminary discussion here.

When superhydrophobicity can be a drag: Ventilated cavitation and splashing effects in hydrofoil and speed-boat models tests

Superhydrophobic surfaces are expected to reduce the hydrodynamic drag on marine vessels due to the lubrication effects of the naturally sustained thin air-layer plastron. By conducting model-tests with a hydrofoil-boat and a speed-boat, we demonstrate that the application of a nanoparticles-deposition-based superhydrophobic coatings on marine vessels can also lead to hydrodynamic effects that significantly increase the drag. In the case of the hydrofoil boat, the use of superhydrophobic coating resulted in plastron-enhanced ventilated cavitation and the formation of water jets that reduce the speed of the boat by more than 30%. In the case of a towed speed-boat, the use of nanoparticle-deposition superhydrophobic coating on the hull affected how the boat splashes water but did not change the net drag on the boat during the transition to the high-speed planing mode of operation. The use of a superhydrophobic coating on the speed-boat propeller was found to inhibit its surface piercing and prohibit the transition to the planing mode, resulting in up to three-time lower speed. These novel effects of the superhydrophobic coating should be accounted for together with the anticipated reduction in friction drag in the design of advanced marine vessels.

Numerical modeling on dynamics of droplet in aircraft wing structure at different velocities

PurposeThe purpose of this paper is to find the droplets impact on the airplane wing structure. Two kinds of characteristics of the droplet at different velocity and viscosity are assumed. The droplet is assumed to be spherical cubic form and it is injected from the convergent divergent nozzle with a passive control.Design/methodology/approachThis paper presents the results of a numerical simulation of droplet impact on the horizontal surface. The effects of impact parameters are studied. The splash effect of the droplet also visualized. The results are presented in form of stress, strain, displacement magnitude of the droplet.FindingsCrosswire is used as passive control. The behavior of the droplet impact is observed based on the kinetic energy and the gravitational forces.Originality/valueThe results predict that smooth particle hydrodynamic designed droplet not only depend on the equation of state of the droplet but also the injection velocity from the nozzle. It also determined that droplet velocity is depending on the viscosity of the fluid.

Laser induced fluorescence investigation on deposited fuel film from spray impingement on viscous film over a solid wall

To quantitatively investigate deposited fuel film characteristics under dry and viscous surface, the laser-induced fluorescence (LIF) method was used in this study. The experiment was done by LIF technique in a laboratory simulation of fuel/lubricant films. Isooctane was used as the surrogate fuel of gasoline and 3-pentanone added as the fluorescent tracer. Viscous oil surface was surrogated by non-fluorescent silicone oil to eliminate the disturbance. The conversion of LIF signal and deposited film mass was followed by a two-dimensional calibration. The experimental results demonstrated that more spray fuel deposited on the pre-existing viscous oil film surface with smaller deposited area because of viscous film buffering and inhibition effects. However, as the injection mass increased, the deposited film characteristics of dry surface deteriorated rapidly, and the difference between dry and viscous film surface was decreased. The deposited film was more sensitive to the impingement angle and silicone oil film thickness than the viscosity and injection pressure. Inclined impingement angle and thin silicone oil film thickness can decrease deposited fuel mass efficiently. High injection pressure also decreased the deposited fuel mass due to better atomization and splash effect. The results also suggested that, during cold starts, the main reason for high soot emission is poor evaporation rather than the interactions between the fuel and walls.

Experimental and modelling evidence of splash effects on manure borne Escherichia coli washoff.

In tropical montane South-East Asia, recent changes in land use have induced increased runoff, soil erosion and in-stream suspended sediment loads. Land use change is also contributing to increased microbial pathogen dissemination and contamination of stream waters. Escherichia coli (E. coli) is frequently used as an indicator of faecal contamination. Field rain simulations were conducted to examine how E. coli is exported from the surface of upland, agricultural soils during runoff events. The objectives were to characterize the loss dynamics of this indicator from agricultural soils contaminated with livestock waste, and to identify the effect of splash on washoff. Experiments were performed on nine 1 m2 plots, amended or not with pig or poultry manure. Each plot was divided into two 0.5 m2 sub-plots. One of the two sub-plots was protected with a mosquito net for limiting the raindrop impact effects. Runoff, soil detachment by raindrop impact and its entrainment by runoff, and E. coli loads and discharge were measured for each sub-plot. The results show that raindrop impact strongly enhances runoff generation, soil detachment and entrainment and E. coli export. When the impact of raindrops was reduced with a mosquito net, total runoff was reduced by more than 50%, soil erosion was on average reduced by 90% and E. coli export from the amended soil surface was on average 3 to 8 times lower. A coupled physics-based approach was performed using the Cast3M platform for modelling the time evolutions of runoff, solid particles detachment and transfer and bacteria transport that were measured for one of the nine plots. After estimation of the saturated hydraulic conductivity, soil erodibility and attachment rate of bacteria, model outputs were consistent with measured runoff coefficients, suspended sediment and E. coli loads. This work therefore underlines the need to maintain adequate vegetation at the soil surface to avoid the erosion and export of soil borne potential pathogens towards downstream aquatic systems.

Direct Shear Strength on the São Francisco River Bank, Northeastern Brazil, With or Without Roots of Different Native Species

Several plant species have been studied as reinforcement elements against landslides at slopes, either to protect against the splash effect offered by shoots or anchoring the soil by the root system. The objective of this work was to investigate the influence of roots from shrub species over the soil mechanical attributes such as cohesion and angle of internal friction at the São Francisco riverbank, northeastern Brazil. A trench was excavated under the treetop of every shrubby individual, sampling blocks at 0-0.25, 0.25-0.50, 0.50-0.75, and 0.75-1.00 m depths. The moisture contents, particle size, liquidity limits, plasticity and actual specific mass of the samples were determined. The soil physical and mechanical attributes such as initial and final specific weight, initial and final void content, initial and final degree of saturation, shear resistance peaks, cohesion, and internal friction angle were identified through direct, elementary, consolidated, and undrained tests. In the samples with Solanum paniculatum, Mimosa pigra species, the highest values for cohesion were registered for the samples with roots. Sesbania virgata presented the greatest variation in cohesion and internal friction angle among samples with and without roots. The position and root status influenced the results of the direct shear tests.

Estimating the Effect of Rain Splash on Soil Particle Transport by Using a Modified Model: Study on Short Hillslopes in Northern China

Splash erosion is an important soil erosion process in sloping lands. This study aims to improve the model of rain splash transport based on the results of previous studies and field experiments involving rainfall simulation. A field study was conducted to examine the effects of rainfall properties, herbaceous cover and surface flow on splash processes on hillslopes in northern China. On the basis of the experimental results, a comprehensive model of rain splash was established through the quantitative analysis of the interactive effects of rainfall kinetic energy, vegetation coverage and overland runoff depth on splash erosion rate and the probability density of splashed particles and maximum splash distance. The results showed that the estimated and observed values of splash transport exhibit high consistency and adaptability. However, several discrepancies were observed between the estimated and observed values for events with high vegetation coverage. These differences can be ascribed to the variation in overland runoff connectivity and the differences in soil surface cohesion at various wetness degrees. The proposed model provides insights into splash erosion characteristics and suggestions for erosion control practices on hillslopes.

A new concept for estimating the influence of vegetation on throughfall kinetic energy using aerial laser scanning

AbstractSoil loss caused by erosion has enormous economic and social impacts. Splash effects of rainfall are an important driver of erosion processes; however, effects of vegetation on splash erosion are still not fully understood. Splash erosion processes under vegetation are investigated by means of throughfall kinetic energy (TKE). Previous studies on TKE utilized a heterogeneous set of plant and canopy parameters to assess vegetation's influence on erosion by rain splash but remained on individual plant‐ or plot‐levels. In the present study we developed a method for the area‐wide estimation of the influence of vegetation on TKE using remote sensing methods. In a literature review we identified key vegetation variables influencing splash erosion and developed a conceptual model to describe the interaction of vegetation and raindrops. Our model considers both amplifying and protecting effect of vegetation layers according to their height above the ground and aggregates them into a new indicator: the Vegetation Splash Factor (VSF). It is based on the proportional contribution of drips per layer, which can be calculated via the vegetation cover profile from airborne LiDAR datasets. In a case study, we calculated the VSF using a LiDAR dataset for La Campana National Park in central Chile. The studied catchment comprises a heterogeneous mosaic of vegetation layer combinations and types and is hence well suited to test the approach. We calculated a VSF map showing the relation between vegetation structure and its expected influence on TKE. Mean VSF was 1.42, indicating amplifying overall effect of vegetation on TKE that was present in 81% of the area. Values below 1 indicating a protective effect were calculated for 19% of the area. For future work, we recommend refining the weighting factor by calibration to local conditions using field‐reference data and comparing the VSF with TKE field measurements. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley &amp; Sons Ltd

High-Frequency Properties of GaN, AlN and InN in Strong Fields

The article proposed a method for modeling and analyzing the high-frequency properties of multi-valley semiconductors, in particular, GaN, AlN and InN. The model is applied to state-of-the-art, promising and relevant materials GaN, AlN and InN, which are now known under the generic name III-nitrides. The method is distinguished by the economical use of computational resources without significant loss of accuracy and the possibility of using both for dynamic tasks over time and variables in the space of fields.The proposed approach is based on solving a system of differential equations, which are known as relaxation equations and are derived from the Boltzmann kinetic equation in the relaxation time approximation by averaging over k-space. In English literature, this method is known as the "method of moments." In contrast to the traditional system of equations for the concentration of carriers, their momentum and energy, here, instead of the energy relaxation equation, the equation for electron temperature is used as a measure of the energy of only chaotic motion. The second significant difference is that the relaxation times are not determined as integral values from the static characteristics of the material, but through averaging the quantum-mechanical scattering rates commonly used in the Monte Carlo method for certain types of scattering. The averaging was performed over the Maxwell distribution function in the electron temperature approximation, as a result of which various mechanisms of carrier scattering through their specific relaxation times are taken into account. Since the system of equations used includes equations in partial derivatives with respect to time and coordinates, it makes it possible to investigate the characteristic manifestations of the impulse properties of the materials under consideration, namely, the time effect of the “overshoot” of drift velocity and the spatial “ballistic transport” of carriers.For the first time, the use of the Fourier transformation of the impulse dependence of the carrier drift velocity to calculate the maximum frequencies inherent in a semiconductor is considered. A connection was found between the shape of the spectral characteristic of the drift velocity and the scattering mechanisms that prevail in a given electric field. The properties of III-nitrides in the frequency domain in a strong electric field are analyzed and compared with existing methods for estimating cut-off frequencies. It is shown that the limiting frequencies increase with increasing electric field strength and amount to hundreds of gigahertz, and for aluminum nitride it exceeds one thousand gigahertz. This is due, apparently, to the greatest for him inter-valley distances and, accordingly, with a weakened inter-valley scattering. The analysis of the spatial manifestation of the splash effect shows the possibility of an almost collisionless, ballistic flight of electrons in a strong field at distances up to hundredths and tenths of a micrometer.Ref. 15, fig. 10, tabl. 1.

Influence of litter source on soil splash rates and organic carbon loss in different soil horizons

Organic litter stabilizes soil particles against the raindrop splash effect. To date, limited research has critically examined the effects of litter quality on soil aggregate detachment and soil organic carbon loss by raindrop splash impact. A study was conducted to determine the effects of different litter sources on quantity of splashed sediments and soil organic carbon (SOC) loss under simulated rainstorm patterns. Soils from seven sieved (&lt; 0.25 mm) horizons mixed with either high-quality Vachellia karroo leaf (C/N = 23.8) and/or low-quality Zea mays stover litter (C/N = 37.4) were incubated in a laboratory for 30 weeks. Splashed sediments and SOC were measured at 1, 3, 8, 14, 23 and 30 weeks of incubation for each soil at 360 mm/h simulated rainfall intensity applied as either single 8-min rainstorm (SR) or 4 × 2-min intermittent rainstorms (IR) separated by a 72-h drying period. Organic litter significantly (P &lt; 0.05) reduced the splashed sediments up to 8 and 14 weeks under IR and SR storms, respectively, and thereafter gradually lost its stabilizing effect on soil aggregates. In order to maintain low quantities of splashed sediments, fresh litter has to be re-applied after this stage. Generally, 13% and 25% more sediments were splashed under IR than SR at 1, 3 and 30, and 8, 14 and 23 weeks after incubation, respectively. Litter quality effect on splash sediments varied across soil horizons but were the same within a soil horizon. Soil horizons with more clay than sand particles had lower quantities of sediments. The SOC loss was influenced by the initial SOC content and primary particle size distribution. Rainstorm pattern and initial SOC content were the main factors that influenced SOC loss. However, more rainstorm patterns should be investigated for these soils.