By taking the Yong River for example in this paper, based on the multiple measured data during 1957 to 2009, the change process of runoff, tide feature, tidal wave, tidal influx and sediment transport are analyzed. Th...By taking the Yong River for example in this paper, based on the multiple measured data during 1957 to 2009, the change process of runoff, tide feature, tidal wave, tidal influx and sediment transport are analyzed. Then a mathematical model is used to reveal the influence mechanism on hydrodynamic characteristics and sediment transport of the wading engineering groups such as a tide gate, a breakwater, reservoirs, bridges and wharves, which were built in different periods. The results showed the hydrodynamic characteristics and sediment transport of the Yong River changed obviously due to the wading engineering groups. The tide gate induced deformation of the tidal wave, obvious reduction of the tidal influx and weakness of the tidal dynamic, decrease of the sediment yield of flood and ebb tide and channel deposition. The breakwater blocked estuarine entrances, resulting in the change of the tidal current and the reduction of the tidal influx in the estuarine area. The large-scale reservoirs gradually made the decrease of the Yong River runoff. The bridge and wharf groups took up cross-section areas, the cumulative affection of which caused the increase of tidal level in the tidal river.展开更多
Vehicle wading is a complex fluid-structure interaction(FSI) problem and has attracted great attention recently from the automotive industry, especially for electric vehicles. As a meshless Lagrangian particle method,...Vehicle wading is a complex fluid-structure interaction(FSI) problem and has attracted great attention recently from the automotive industry, especially for electric vehicles. As a meshless Lagrangian particle method, smoothed particle hydrodynamics(SPH) is one of the most suitable candidates for simulations of vehicle wading due to its inherent advantages in modeling free surface flows, splash, and moving interfaces. Nevertheless, the inevitable neighbor query for the nearest adjacent particles among the support domain leads to considerable computational cost and thus limits its application in 3D large-scale simulations. In this work, a GPU-based SPH method is developed with an adaptive spatial sort technology for simulations of vehicle wading. In addition, a fast, easy-to-implement particle generator is presented for isotropic initialization of the complex vehicle geometry with optimal interpolation properties. A comparative study of vehicle wading on a puddle between the GPUbased SPH with two pieces of commercial software is used to verify the capability of the GPU-based SPH method in terms of convergence analysis, kinematic characteristics, and computing performance. Finally, different conditions of vehicle speeds, water depths, and puddle widths are tested to investigate the vehicle wading numerically. The results demonstrate that the adaptive spatial sort technology can significantly improve the computing performance of the GPU-based SPH method and meanwhile promotes the GPU-based SPH method to be a competitive tool for the study of 3D large-scale FSI problems including vehicle wading. Some helpful findings of the critical vehicle speed, water depth as well as boundary wall effect are also reported in this work.展开更多
Diverse spatio-temporal aspects of avian migration rely on relatively rigid endogenous programs.However,flexibility in migratory behavior may allow effective coping with unpredictable variation in ecological condition...Diverse spatio-temporal aspects of avian migration rely on relatively rigid endogenous programs.However,flexibility in migratory behavior may allow effective coping with unpredictable variation in ecological conditions that can occur during migration.We aimed at characterizing inter-and intraindividual variation of migratory behavior in a forest-dwelling wader species,the Eurasian woodcock Scolopax rusticola,focusing on spatio-temporal consistency across repeated migration episodes.By satellite-tracking birds from their wintering sites along the Italian peninsula to their breeding areas,we disclosed a remarkable variability in migration distances,with some birds flying more than 6,000 km to Central Asian breeding grounds(up to 101°E).Prebreeding migration was faster and of shorter duration than postbreeding migration.Birds moving over longer distances migrated faster during prebreeding migration,and those breeding at northernmost latitudes left their wintering areas earlier.Moreover,birds making longer migrations departed earlier from their breeding sites.Breeding site fidelity was very high,whereas fidelity to wintering areas increased with age.Migration routes were significantly consistent,both among repeated migration episodes and between pre-and postbreeding migration.Prebreeding migration departure date was not significantly repeatable,whereas arrival date to the breeding areas was highly repeatable.Hence,interindividual variation in migratory behavior of woodcocks was mostly explained by the location of the breeding areas,and spatial consistency was relatively large through the entire annual cycle.Flexibility in prebreeding migration departure date may suggest that environmental effects have a larger influence on temporal than on spatial aspects of migratory behavior.展开更多
基金financially supported by the National Science Foundation for Distinguished Young Scholars of China(Grant No.51125034)the National Natural Science Foundation of China(Grant Nos.51279046 and 50909037)the Fundamental Research Funds for the Central Universities(Grant No.2010B01114)
文摘By taking the Yong River for example in this paper, based on the multiple measured data during 1957 to 2009, the change process of runoff, tide feature, tidal wave, tidal influx and sediment transport are analyzed. Then a mathematical model is used to reveal the influence mechanism on hydrodynamic characteristics and sediment transport of the wading engineering groups such as a tide gate, a breakwater, reservoirs, bridges and wharves, which were built in different periods. The results showed the hydrodynamic characteristics and sediment transport of the Yong River changed obviously due to the wading engineering groups. The tide gate induced deformation of the tidal wave, obvious reduction of the tidal influx and weakness of the tidal dynamic, decrease of the sediment yield of flood and ebb tide and channel deposition. The breakwater blocked estuarine entrances, resulting in the change of the tidal current and the reduction of the tidal influx in the estuarine area. The large-scale reservoirs gradually made the decrease of the Yong River runoff. The bridge and wharf groups took up cross-section areas, the cumulative affection of which caused the increase of tidal level in the tidal river.
基金supported by the Laoshan Laboratory(Grant No.LSKJ202202000)National Natural Science Foundation of China(Grant Nos.12032002,and U22A20256)Natural Science Foundation of Beijing(Grant No.L212023)。
文摘Vehicle wading is a complex fluid-structure interaction(FSI) problem and has attracted great attention recently from the automotive industry, especially for electric vehicles. As a meshless Lagrangian particle method, smoothed particle hydrodynamics(SPH) is one of the most suitable candidates for simulations of vehicle wading due to its inherent advantages in modeling free surface flows, splash, and moving interfaces. Nevertheless, the inevitable neighbor query for the nearest adjacent particles among the support domain leads to considerable computational cost and thus limits its application in 3D large-scale simulations. In this work, a GPU-based SPH method is developed with an adaptive spatial sort technology for simulations of vehicle wading. In addition, a fast, easy-to-implement particle generator is presented for isotropic initialization of the complex vehicle geometry with optimal interpolation properties. A comparative study of vehicle wading on a puddle between the GPUbased SPH with two pieces of commercial software is used to verify the capability of the GPU-based SPH method in terms of convergence analysis, kinematic characteristics, and computing performance. Finally, different conditions of vehicle speeds, water depths, and puddle widths are tested to investigate the vehicle wading numerically. The results demonstrate that the adaptive spatial sort technology can significantly improve the computing performance of the GPU-based SPH method and meanwhile promotes the GPU-based SPH method to be a competitive tool for the study of 3D large-scale FSI problems including vehicle wading. Some helpful findings of the critical vehicle speed, water depth as well as boundary wall effect are also reported in this work.
基金They acknowledge support by Parco Nazionale della Majella,Parco Naturale La Mandria,Parco Regionale dei Colli Euganei,and Parco Regionale dei Monti PicentiniPartial financial support was provided by Regione Veneto,ATC Salerno 2,ATC Avellino,ATC Benevento,ATC Caserta,ATC Napoli,ATC Macerata 2,ATC Frosinonc 1,ATC Cosenza 1,ATC Vastese,ATC Foggia,ATC Genova,ATC La Spezia,Comprensorio Alpino Torino 4,Provincia di Udine,M.Gemin,local FIDC sections(Roma,Umbria,Lombardia),and Ente Nazionale della Cinofilia.
文摘Diverse spatio-temporal aspects of avian migration rely on relatively rigid endogenous programs.However,flexibility in migratory behavior may allow effective coping with unpredictable variation in ecological conditions that can occur during migration.We aimed at characterizing inter-and intraindividual variation of migratory behavior in a forest-dwelling wader species,the Eurasian woodcock Scolopax rusticola,focusing on spatio-temporal consistency across repeated migration episodes.By satellite-tracking birds from their wintering sites along the Italian peninsula to their breeding areas,we disclosed a remarkable variability in migration distances,with some birds flying more than 6,000 km to Central Asian breeding grounds(up to 101°E).Prebreeding migration was faster and of shorter duration than postbreeding migration.Birds moving over longer distances migrated faster during prebreeding migration,and those breeding at northernmost latitudes left their wintering areas earlier.Moreover,birds making longer migrations departed earlier from their breeding sites.Breeding site fidelity was very high,whereas fidelity to wintering areas increased with age.Migration routes were significantly consistent,both among repeated migration episodes and between pre-and postbreeding migration.Prebreeding migration departure date was not significantly repeatable,whereas arrival date to the breeding areas was highly repeatable.Hence,interindividual variation in migratory behavior of woodcocks was mostly explained by the location of the breeding areas,and spatial consistency was relatively large through the entire annual cycle.Flexibility in prebreeding migration departure date may suggest that environmental effects have a larger influence on temporal than on spatial aspects of migratory behavior.
