Drift Simulation Research Articles

雪庇・着雪現象を考慮した吹雪数値シミュレーションの検討－その2，建築物に生じた雪庇事例の再現と検証－

雪庇・着雪現象を考慮した吹雪数値シミュレーションの検討－その2，建築物に生じた雪庇事例の再現と検証－

Estimation of hydrodynamic derivatives of a container ship using PMM simulation in OpenFOAM

Static drift, pure sway and pure yaw simulation results are determined for a container ship. For simulation, open source RANS solver, OpenFOAM was used. The simulation results were compared with two sets of experimental data. Next, hydrodynamic derivatives were predicted from simulation results and compared with experimental ones. The results show good agreement with experimental data, except for some pure yaw cases. Overall, the paper concludes that OpenFOAM is well capable of estimating hydrodynamic derivatives maintaining reasonable accuracy and computational efficiency.

Crescimento inicial de Jatropa curcas L. sob doses de fósforo e deriva de glyphosate

The objective of this study was to evaluate the initial growth of jatropha (Jatropa curcas L.) plants under the effect of phosphate fertilization and simulation of glyphosate drift. The experiment was conducted using plastic vessels, conditioned under field conditions. A randomized block design, in a 3 x 5 factorial scheme, three doses of phosphorus (0, 40 and 80 kg ha-1 of P2O5) and five doses of glyphosate (0, 1.1, 3.3, 10 e 30 g ha-1) with four replicates. Leaf area, total dry matter, lignin and cellulose content, foliar phosphorus content, and gas exchange were evaluated. It was concluded that fertilizations from 40 kg ha-1 presented on average the largest increases in: leaf area; total dry matter; phosphorus content and for liquid photosynthesis. The simulation doses of glyphosate drift above 30 g ha-1 may impair the growth of jatropha plants considering the following variables: total dry matter, lignin content and cellulose and protein. Phosphate fertilization may render jatropha plants tolerant to glyphosate drift simulation doses.

USE OF LIQUID FERTILIZER TO REDUCE THE PHYTOTOXIC EFFECTS OF GLYPHOSATE ON EUCALYPTUS

ABSTRACT Glyphosate is a non-selective herbicide used for weed control in eucalyptus forests. Glyphosate drifts are common and may cause serious damage to crops. An alternative to reduce such effects is to use antidotes capable of protecting eucalyptus. An experiment was conducted to evaluate the effects of the application of liquid fertilizer on eucalyptus plants subjected to a glyphosate drift simulation. The treatments were arranged in a 5 x 5 factorial design. The first corresponding factor was liquid fertilizer (0, 1, 2, 4, and 8 L c.p. ha -1 of Fertiactyl Pós®) and the second factor dose of glyphosate drift (0, 360, 720, 1,440, and 2,160 g e.a. ha -1). The products were applied together so that the spray did not reach the upper third of the plants. At 7, 28, and 49 days after application (DAA), the percentage of intoxication of eucalyptus was evaluated. At 56 days DAA, height, leaf area, leaf nutrient contents, and shoot and root dry matter were determined. Higher doses of glyphosate (1,440 and 2,160 g ha -1) caused intoxication levels above 90% at 28 and 49 DAA without using liquid fertilizer. The combination of 2,160 g ha -1 of glyphosate with 8.0 L ha -1 of liquid fertilizer resulted in an estimated eucalyptus dry matter 7% higher than in the control and 97% higher than using 2,160 g ha -1 of glyphosate without the liquid fertilizer. We conclude that the liquid fertilizer was effective in suppressing the harmful effects caused by glyphosate on eucalyptus plants.

地球シミュレータIIによる海上流出油の漂流・拡散シミュレーション( 輸送の三原則を統合した国際海上輸送創出の研究)

地球シミュレータIIによる海上流出油の漂流・拡散シミュレーション( 輸送の三原則を統合した国際海上輸送創出の研究)

Solar effect on the Rayleigh-Taylor instability growth rate as simulated by the NCAR TIEGCM

The TIEGCM (Thermosphere Ionosphere Electrodynamics General Circulation Model) is used to investigate the solar effect on the equatorial ionospheric Rayleigh-Taylor (R-T) instability growth rate, which is responsible for the occurrence of the plasma bubbles. The R-T growth rate is calculated for the solar maximum year 2003 and minimum 2009. The growth rate is strongly dependent on the solar activity. During solar maximum, the pre-reversal enhancement is much stronger leading to higher R-T growth rate. The R-T growth rates from the TIEGCM follow the same solar dependence as the observed occurrence of equatorial plasma bubbles by DMSP satellites. The R-T growth rate also enhances when the day/night terminator is parallel to the magnetic field line near the equator. The R-T growth rate does not correlate well with the solar F10.7 index on a short time scale (~10 days) because the field-line integrated electron content gradient cancels out the positive correlation between the vertical ion drift with the F10.7 index. The TIEGCM result shows the importance of the electron content gradient to the R-T growth rate and the plasma bubble occurrence. The bubble occurrence rates were estimated based on the vertical ion drift simulation results.

Drift coefficient and simulation of amino acid-solvent interactions for proteins whose main chain have \alpha-helical secondary structures

Drift coefficient and simulation of amino acid-solvent interactions for proteins whose main chain have \alpha-helical secondary structures

GLYPHOSATE DRIFT IN EUCALYPTUS PLANTS

ABSTRACTWith the present study we aim to assess the damage caused to Eucalyptus plants exposed to glyphosate drift in different canopy portions. The drift simulation was carried out through application of 1,080 g ha-1 of glyphosate in five canopy portions (0, 25, 50, 75 and 100% of the low branches), in four areas of cultivation. Areas I and II, plants with 0.91 and 2.98 m, and height of canopy drift exposition of 0.30 and 1.0 m, respectively. In areas III and IV both cultivations were 8.15 m high, varying the height of drift exposition between 2.0 and 2.5 m, respectively. At 30 and 480 days after application (DAA), the survival rate was assessed, and at 300 and 480 DAA diameter at breast height (DBH), height, volume and their respective increment were determined. The medium annual increment (MAI) was determined at 480 DAA. Area I, in which the plants were 0.91 m high, we observed that treatment with 100% of the low branches exposed to drift led to stand reduction of the plants around 18.75 and 38.19% at 30 and 480 DAA, respectively. Areas I and II showed reduction in plant growth in height and DBH, wood volume and MAI, to the extent that there was an increase in the portion of canopy exposed to glyphosate drift. However, in areas III and IV, in which 8.15 m height plants were found, no changes were verified for the evaluated characteristics, regardless of the portion of canopy exposed to glyphosate drift.

The Temporal and Energy Peculiarities of High Energy Electron Bursts in the Earth's Magnetosphere

Using longitudinal particles drift simulation results, energy spectrum dynamics of burst electrons in ARINA and VSPLESK experiments have been carried out. Robust regression analysis technique is proposed to select burst electrons from background albedo particles. The proposed technique increases quality of experimental data and helps more precisely determine particle precipitation region from radiation belt.

Simulation and Analysis of the Temperature-Compensated FBAR

The property of temperature-frequency drift has an effect on the passband ripples, center frequency and insertion loss of FBAR filters, reducing the reliability of its electrical application. A temperature-frequency drift simulation of a typical Mo/AlN/Mo FBAR is achieved by means of finite element analysis software ANSYS, the simulated temperature coefficient of frequency is about-35ppm/°C within the temperature range of-50°C~150°C. By adding a compensated layer with positive temperature coefficient in the FBAR structure, the effects of the compensated layer thickness on temperature-frequency drift, resonant frequency and electromechanical coupling are analyzed. The simulated temperature coefficient of frequency of designed temperature compensated FBAR, which composed of Mo/AlN/SiO2/Mo, is about 0.8ppm/°C, the property of temperature-frequency drift is effectively improved.

A realistic freshwater forcing protocol for ocean-coupled climate models

A high-end scenario of polar ice loss from the Greenland and Antarctic ice sheet is presented with separate projections for different mass-loss sites up to the year 2100. For each large ice sheet three potential sources of freshwater release to the ocean are considered: run-off from surface melt, basal melt through heat exchange with the ocean, and iceberg calving and subsequent mass loss through melt of drifting icebergs. The location and relative magnitude of freshwater forcing due to drifting icebergs is calculated from a separate iceberg drift simulation. We assume fixed annual spatial patterns with magnitudes varying in time. These magnitudes are based on a severe warming scenario based on expert elicitation. The resultant freshwater forcing is applied to a global climate model and the effects on sea-level rise are discussed. The simulations show strong sea level rise on the Antarctic continental shelves. The effect on the Atlantic overturning circulation is very small, however.

Ion drift simulation of sudden appearance of sub-keV structured ions in the inner magnetosphere

Abstract. Energy–latitude dispersed structured sub-keV ions in the inner magnetosphere often show significant development or intensification (by more than factor of 3) within 1–2 h near noon or afternoon where the azimuthal ion drift velocity at the sub-keV range is expected to be near zero. To examine whether such sudden appearances in the dayside can be explained by the drift motion of ions that are formed during substorm-related injections, we numerically simulated two such examples, one at noon and the other in the afternoon, based on the ion drift model. For both cases, the ion drift model with finite duration of proton source in the nightside can explain the observed large inbound–outbound differences in the sub-keV proton population without any new sources. Ion drift motion can thus cause rapid changes of complicated ion populations, at remote places from the source a long time after the substorm activities.

抜海漁港周辺の漂砂特性への吹送流の影響

In Bakkai Fishing Port where the sand drift phenomenon has been occurring, the burial of the port and the channel is longstanding problem. Generally, a sand drift simulation at a coastal area where tidal fluctuation is small, only wave-induced currents are considered. However, at this area, waves are interrupted by Islands and merely weak currents are generated. On the other hand, this area is high wind site, so there is a possibility that the currents due to wind influence the flow environment. In this paper, (1) we figured out the sand movement and its generation mechanism from observation data and flow property. (2) We proposed the new method of estimating the currents due to wind in the long-time projection of geographical change, and confirmed the improvements of degree of projection reproducibility.

Collision Analysis of Container Drifted by Runup Tsunami Using Drift Collision Coupled Model

This study proposes analyzing tsunami generation and propagation of tsunamis, wave runup onto land, object drift, collision with other structures, deformation prediction of colliding and collided-with, and collision force estimation. To reduce calculation load in using the LS-DYNA collision model, we use a drift model using the immersed boundary (IB) method from wave generation to just before collision, and the collision model is used during the collision phase, in which numerical data calculated using the drift model are used as an initial condition of the collision model. Validity of the drift model for wave level, wave force, and drift behavior of a container were verified through comparison with experimental data measured in laboratory experiments. Collision model predictability was also confirmed in terms of drift collision force. Fluid-structure interaction (FSI) between the container and the runup wave is reproduced in numerical drift collision analysis. Through this analysis of a full-scale container based on the international standard with a concrete column, we confirmed the applicability of the collision analysis using the drift simulation as an initial condition for an actual field.

Efeito da deriva simulada de glyphosate no crescimento inicial de plantas de pinhão-manso

Objetivou-se avaliar o efeito da deriva simulada do herbicida glyphosate no crescimento inicial de plantas de pinhão-manso (Jatropha curcas) em casa de vegetação. Para simulação da deriva de glyphosate, utilizaram-se as seguintes doses: 0,0; 1,4; 2,8; 5,6; 11,3; 22,5; 45,0; 90,0; 180,0; e 360,0 g ha-1 de glyphosate, distribuídas em blocos casualizados, com quatro repetições. O glyphosate foi aplicado 51 dias após a semeadura, quando as plantas de pinhão-manso apresentavam entre 16 e 18 folhas completamente desenvolvidas e altura média de 45 cm. As aplicações das doses foram feitas com pulverizador costal pressurizado a CO 2, regulado para proporcionar 200 L ha-1. Os resultados indicam que a altura, o diâmetro do caule, a área foliar, bem como a massa seca de folha, caule e raiz das plantas de pinhão-manso, apresentaram reduções após a simulação da deriva de glyphosate, em relação à testemunha. Dessa forma, pode-se concluir que o desenvolvimento inicial das plantas de pinhão-manso foi influenciado pela deriva simulada de glyphosate; a deriva de doses superiores a 45,0 g ha-1 pode ser severamente prejudicial às plantas no período de 41 dias após a aplicação.

Development of a High Pressure Xe Ionization Chamber for Environmental Radiation Spectroscopy

A High Pressure Xenon ionization chamber is a promising radiation detector for environmental radiation measurement due to its radiation hardness, its physical rigidity, and its capability of operation at a high temperature up to about 170 °C. A cylindrical high pressure xenon ionization chamber, which was configured with a shielding mesh to improve its energy resolution, was designed on the basis of an electron transfer simulation code (EGSnrc) to extract an optimal density of Xe gas and a thickness of the chamber wall. An electron drift simulation code, Garfield, which was coupled with a Maxwell electric filed calculator, was also employed for the electron drift simulations due to the geometry of the shielding mesh. Shielding inefficiency was also calculated. A spherical ionization chamber was also designed and fabricated to monitor environmental radiation. A noble gas system was constructed to create a noble gas with a high purity and to inject the noble gas up to 60 atm. The combination of an oxygen absorbent (Oxisorb), a molecular sieve, and a high temperature getter can minimize the electro-negative impurities, such as the O2 and N2 gas, to below about several ppb levels. Preliminary tests such as leakage currents, saturation currents, and gas leak test were performed. The performance of the two fabricated ionization chambers at a low dose rate was tested by using a conventional shadow technique with a NIST certified 33.52 MBq 226Ra source in the calibration room at KAERI.

Estimation of the Distribution of Marine Litter by using the Drift Simulation Model in the Seto Inland Sea

The drift numerical simulation model of the Seto Inland Sea with 0.5' mesh was constructed to search for problem of marine litter in the sea. The particles assumed to the floating litter were released from 13 rivers in these models and were traced for 30 days. As a result, the drift route, the arrival place, and the arrival time of the floating litter became clear. Moreover, the distribution of the amount of litter assuming proportion to the river discharge was calculated. A lot of amounts of the floating litter were distributed around the Okinose in the Osaka bay. They weredischarged from Yodo River. Also, the dispersion area of the floating litter was not proportional to the river discharge. This result was shown that the extension of the litter depended on the flow in the sea and the close of topography.

Mapping monthly rainfall data in Galicia (NW Spain) using inverse distances and geostatistical methods

Abstract. In this paper, results from three different interpolation techniques based on Geostatistics (ordinary kriging, kriging with external drift and conditional simulation) and one deterministic method (inverse distances) for mapping total monthly rainfall are compared. The study data set comprised total monthly rainfall from 1998 till 2001 corresponding to a maximum of 121 meteorological stations irregularly distributed in the region of Galicia (NW Spain). Furthermore, a raster Geographic Information System (GIS) was used for spatial interpolation with a 500×500 m grid digital elevation model. Inverse distance technique was appropriate for a rapid estimation of the rainfall at the studied scale. In order to apply geostatistical interpolation techniques, a spatial dependence analysis was performed; rainfall spatial dependence was observed in 33 out of 48 months analysed, the rest of the rainfall data sets presented a random behaviour. Different values of the semivariogram parameters caused the smoothing in the maps obtained by ordinary kriging. Kriging with external drift results were according to former studies which showed the influence of topography. Conditional simulation is considered to give more realistic results; however, this consideration must be confirmed with new data.

Numerical and Experimental Study on Drift due to Tsunami for Several Drifting Bodies

In order to predict the behavior of floating body under tsunami flood appropriately, it is significant to evaluate the drag force exerted on the float shape when reproducing the dynamics with drift. So, we prepared the drift simulation model based on the Distinct Element Method (DEM). In the simulation, every flotsam shape was expressed by an assembly of individual sphere elements and current velocity field generated by tsunami was given from the result of the tsunami propagation simulation computed in advance. This paper shows experimental results of car's drag force coefficient as a function of every current angle. And we report the application of the drift simulation method by comparing the drift motion from the experiment in a 2-dimensional plane water tank with that of the simulation result.

浮体特性を考慮した漂流シミュレーションの適用性に関する研究

In order to predict the behavior of floating body under tsunami flood appropriately, numerical simulation is effective to reproduce the dynamics with drift. As analyzing the movement of flotsam, it is significant to evaluate the drag force exerted on the float shape.We prepared the drift simulation model based on the Distinct Element Method (DEM). In the simulation, every flotsam shape was expressed by an assembly of individual sphere elements and current velocity field generated by tsunami was given from the result of the tsunami propagation simulation computed in advanceThis paper shows experimental results of container's drag force coefficient as a function of every current angle. And we refer the application of a drift simulation method considering the drag force by comparing the drift motion obtained from the experiment in a 2-dimensional plane water tank with that of the simulation result for above-mentioned float model.