A coupled numerical method for the direct numerical simulation of particle-fluid systems is formulated and implemented, resolving an order of magnitude smaller than particle size. The particle motion is described by t...A coupled numerical method for the direct numerical simulation of particle-fluid systems is formulated and implemented, resolving an order of magnitude smaller than particle size. The particle motion is described by the time-driven hard-sphere model, while the hydrodynamic equations governing fluid flow are solved by the lattice Boltzmann method （LBM）, Particle-fluid coupling is realized by an immersed boundary method （IBM）, which considers the effect of boundary on surrounding fluid as a restoring force added to the governing equations of the fluid. The proposed scheme is validated in the classical flow-around-cylinder simulations, and preliminary application of this scheme to fluidization is reported, demonstrating it to be a promising computational strategy for better understanding complex behavior in particle-fluid systems.展开更多
Modelling the impact of climate change on cropping systems is crucial to support policy-making for farmers and stakeholders.Nevertheless,there exists inherent uncertainty in such cases.General Circulation Models(GCMs)...Modelling the impact of climate change on cropping systems is crucial to support policy-making for farmers and stakeholders.Nevertheless,there exists inherent uncertainty in such cases.General Circulation Models(GCMs)and future climate change scenarios(different Representative Concentration Pathways(RCPs)in different future time periods)are among the major sources of uncertainty in projecting the impact of climate change on crop grain yield.This study quantified the different sources of uncertainty associated with future climate change impact on wheat grain yield in dryland environments(Shiraz,Hamedan,Sanandaj,Kermanshah and Khorramabad)in eastern and southern Iran.These five representative locations can be categorized into three climate classes:arid cold(Shiraz),semi-arid cold(Hamedan and Sanandaj)and semi-arid cool(Kermanshah and Khorramabad).Accordingly,the downscaled daily outputs of 29 GCMs under two RCPs(RCP4.5 and RCP8.5)in the near future(2030s),middle future(2050s)and far future(2080s)were used as inputs for the Agricultural Production Systems sIMulator(APSIM)-wheat model.Analysis of variance(ANOVA)was employed to quantify the sources of uncertainty in projecting the impact of climate change on wheat grain yield.Years from 1980 to 2009 were regarded as the baseline period.The projection results indicated that wheat grain yield was expected to increase by 12.30%,17.10%,and 17.70%in the near future(2030s),middle future(2050s)and far future(2080s),respectively.The increases differed under different RCPs in different future time periods,ranging from 11.70%(under RCP4.5 in the 2030s)to 20.20%(under RCP8.5 in the 2080s)by averaging all GCMs and locations,implying that future wheat grain yield depended largely upon the rising CO2 concentrations.ANOVA results revealed that more than 97.22% of the variance in future wheat grain yield was explained by locations,followed by scenarios,GCMs,and their interactions.Specifically,at the semi-arid climate locations(Hamedan,Sanandaj,Kermanshah and Khorramabad),most of the variations arose from the scenarios(77.25%),while at the arid climate location(Shiraz),GCMs(54.00%)accounted for the greatest variation.Overall,the ensemble use of a wide range of GCMs should be given priority to narrow the uncertainty when projecting wheat grain yield under changing climate conditions,particularly in dryland environments characterized by large fluctuations in rainfall and temperature.Moreover,the current research suggested some GCMs(e.g.,the IPSL-CM5B-LR,CCSM4,and BNU-ESM)that made moderate effects in projecting the impact of climate change on wheat grain yield to be used to project future climate conditions in similar environments worldwide.展开更多
As the world's largest potato producer,China plays a crucial role in global food security.However,the impacts of climate change on both the potential planting regions and climatic suitability of potato cultivation...As the world's largest potato producer,China plays a crucial role in global food security.However,the impacts of climate change on both the potential planting regions and climatic suitability of potato cultivation in China remain poorly quantified.In this study,potato planting zones were delineated based on the thermal requirements of potato,utilizing the temperature data from 2177 meteorological sites during 1961-2020.A comprehensive climatic suitability index(CCSI)was developed by integrating temperature,light,and precipitation suitability indices,weighted through Agricultural Production Systems Simulator(APSIM)-Potato model simulation.During 1991-2020,compared to 1961-1990,the unsuitable and single-season planting regions decreased by 18%and 8%,while the multiseason and winter planting regions expanded by 93%and 6%,respectively.During 1961-2020,the CCSI was highest in single-season planting regions(e.g.,Northeast China and the north agro-pastoral ecotone),followed by multi-season and winter planting regions.During 1991-2020,compared to 1961-1990,CCSI of potato planting in the singleseason planting region showed a slight decrease,but it increased by 1%-2%in the multi-season and winter planting regions.These findings demonstrate that the increase in potato climate suitability supports the expansion of potato planting area and implementation of the“Potato as Staple Food”policy.Increased precipitation and temperature identify Northwest and Southwest China as the potential expansion regions for potato planting.展开更多
基金sponsored by Ministry of Finance under the grant ZDYZ2008-2National Key Science and Technology Project under the grant 2008ZX05014-003-006HZthe Chinese Academy of Sciences under the grant KGCX2-YW-124
文摘A coupled numerical method for the direct numerical simulation of particle-fluid systems is formulated and implemented, resolving an order of magnitude smaller than particle size. The particle motion is described by the time-driven hard-sphere model, while the hydrodynamic equations governing fluid flow are solved by the lattice Boltzmann method （LBM）, Particle-fluid coupling is realized by an immersed boundary method （IBM）, which considers the effect of boundary on surrounding fluid as a restoring force added to the governing equations of the fluid. The proposed scheme is validated in the classical flow-around-cylinder simulations, and preliminary application of this scheme to fluidization is reported, demonstrating it to be a promising computational strategy for better understanding complex behavior in particle-fluid systems.
基金funded by the Deputy of Research Affairs, Lorestan University, Iran (Contract No. 1400-6-02-518-1402)
文摘Modelling the impact of climate change on cropping systems is crucial to support policy-making for farmers and stakeholders.Nevertheless,there exists inherent uncertainty in such cases.General Circulation Models(GCMs)and future climate change scenarios(different Representative Concentration Pathways(RCPs)in different future time periods)are among the major sources of uncertainty in projecting the impact of climate change on crop grain yield.This study quantified the different sources of uncertainty associated with future climate change impact on wheat grain yield in dryland environments(Shiraz,Hamedan,Sanandaj,Kermanshah and Khorramabad)in eastern and southern Iran.These five representative locations can be categorized into three climate classes:arid cold(Shiraz),semi-arid cold(Hamedan and Sanandaj)and semi-arid cool(Kermanshah and Khorramabad).Accordingly,the downscaled daily outputs of 29 GCMs under two RCPs(RCP4.5 and RCP8.5)in the near future(2030s),middle future(2050s)and far future(2080s)were used as inputs for the Agricultural Production Systems sIMulator(APSIM)-wheat model.Analysis of variance(ANOVA)was employed to quantify the sources of uncertainty in projecting the impact of climate change on wheat grain yield.Years from 1980 to 2009 were regarded as the baseline period.The projection results indicated that wheat grain yield was expected to increase by 12.30%,17.10%,and 17.70%in the near future(2030s),middle future(2050s)and far future(2080s),respectively.The increases differed under different RCPs in different future time periods,ranging from 11.70%(under RCP4.5 in the 2030s)to 20.20%(under RCP8.5 in the 2080s)by averaging all GCMs and locations,implying that future wheat grain yield depended largely upon the rising CO2 concentrations.ANOVA results revealed that more than 97.22% of the variance in future wheat grain yield was explained by locations,followed by scenarios,GCMs,and their interactions.Specifically,at the semi-arid climate locations(Hamedan,Sanandaj,Kermanshah and Khorramabad),most of the variations arose from the scenarios(77.25%),while at the arid climate location(Shiraz),GCMs(54.00%)accounted for the greatest variation.Overall,the ensemble use of a wide range of GCMs should be given priority to narrow the uncertainty when projecting wheat grain yield under changing climate conditions,particularly in dryland environments characterized by large fluctuations in rainfall and temperature.Moreover,the current research suggested some GCMs(e.g.,the IPSL-CM5B-LR,CCSM4,and BNU-ESM)that made moderate effects in projecting the impact of climate change on wheat grain yield to be used to project future climate conditions in similar environments worldwide.
基金Supported by the Science and Technology Program of Inner Mongolia(2025KJHZ0003)Strategic Priority Research Program of the Chinese Academy of Sciences(XDA28060200)+2 种基金Basic Research Fund of Chinese Academy of Meteorological Sciences(CAMS)(2024Y011,2024Z001,and 2023Z014)Key Innovative Team of Agricultural Meteorology of China Meteorological Administration(CMA2024ZD02)Science and Technology Development Fund of CAMS(2024KJ010)。
文摘As the world's largest potato producer,China plays a crucial role in global food security.However,the impacts of climate change on both the potential planting regions and climatic suitability of potato cultivation in China remain poorly quantified.In this study,potato planting zones were delineated based on the thermal requirements of potato,utilizing the temperature data from 2177 meteorological sites during 1961-2020.A comprehensive climatic suitability index(CCSI)was developed by integrating temperature,light,and precipitation suitability indices,weighted through Agricultural Production Systems Simulator(APSIM)-Potato model simulation.During 1991-2020,compared to 1961-1990,the unsuitable and single-season planting regions decreased by 18%and 8%,while the multiseason and winter planting regions expanded by 93%and 6%,respectively.During 1961-2020,the CCSI was highest in single-season planting regions(e.g.,Northeast China and the north agro-pastoral ecotone),followed by multi-season and winter planting regions.During 1991-2020,compared to 1961-1990,CCSI of potato planting in the singleseason planting region showed a slight decrease,but it increased by 1%-2%in the multi-season and winter planting regions.These findings demonstrate that the increase in potato climate suitability supports the expansion of potato planting area and implementation of the“Potato as Staple Food”policy.Increased precipitation and temperature identify Northwest and Southwest China as the potential expansion regions for potato planting.
