Apart from the direct threat to human lives, the flood waves as a result of the rapid catchment response to intense rainfall, breaches of flood defences, tsunamis or storm surges may induce huge impact forces on struc...Apart from the direct threat to human lives, the flood waves as a result of the rapid catchment response to intense rainfall, breaches of flood defences, tsunamis or storm surges may induce huge impact forces on structures, causing structural damage or even failures. Most existing design codes do not properly account for these impact forces due to the limited understanding of the underlying physical processes and the lack of reliable empirical formulae or numerical approaches to quantifying them. This paper presents laboratory experiments to better understand the interaction between the extreme flow hydrodynamics and the hydraulic structures and uses the measured data to validate a numerical model. The model solves the two-dimensional shallow water equations using a finite volume Godunov-type scheme for the reliable simulation of complex flow hydrodynamics. New model components are developed for estimating the hydrostatic and hydrodynamic pressure to quantify the flow impact on structures. The model is applied to reproduce two selected experiment tests with different settings and satisfactory numerical results are obtained, which confirms its predictive capability. The model will therefore provide a potential tool for wider and more flexible field-scale applications.展开更多
Blcod flow of the extremities was measured in 33 cases of rheumatoid arthritis and 30 ofhealthy persons by personal vascular laboratory. It was found that the values of extremity rheography in thepatients were signiti...Blcod flow of the extremities was measured in 33 cases of rheumatoid arthritis and 30 ofhealthy persons by personal vascular laboratory. It was found that the values of extremity rheography in thepatients were signiticantly lower than that in the controls . Treated with blood-circiJIation-promoting and stasis-removing traditional Chinese medicine and Mailuoning(脉络宁) Injection which has a beneficial impact on an-ti-coagulation. removing embolus and activating circtJIation, tlie symptoms, signs and tlie blood flow in theextremities otthe patients with rheumatoid arthritis were markedly improved.展开更多
The tidal limit is the key interface indicating whether water levels will be affected by tidal waves, which is of great significance to navigation safety and regional flood control. Due to limitations in research meth...The tidal limit is the key interface indicating whether water levels will be affected by tidal waves, which is of great significance to navigation safety and regional flood control. Due to limitations in research methods, recent changes in the Yangtze River tidal limit, caused by sea level rise and large-scale engineering projects, urgently need to be studied. In this study,spectrum analysis was undertaken on measured water level data from downstream Yangtze River hydrological stations from2007 to 2016. The bounds of the tidal limit were identified through comparisons between the spectra and red noise curves, and the fluctuation range and characteristics were summarized. The results showed that:(1) During the extremely dry period, when the flow rate at Jiujiang station was about 8440 m3 s-1, the tidal limit was near Jiujiang; whereas during the flood season, when the flow rate at Jiujiang station was about 66700 m3 s-1, the tidal limit was between Zongyang Sluice and Chikou station.(2)From the upper to lower reach, the effect of the Jiujiang flow rate on the tidal limit weakens, while the effect of the Nanjing tidal range increases. The tidal limit fluctuates under similar flow rates and tidal ranges, and the fluctuation range increases with increasing flow rate and decreasing tidal range.(3) With the continued influence of rising sea levels and construction in river basin estuaries, the tidal limit may move further upstream.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51379074,51411130125)the Chinese Government "Recruitment Program of Global Experts"
文摘Apart from the direct threat to human lives, the flood waves as a result of the rapid catchment response to intense rainfall, breaches of flood defences, tsunamis or storm surges may induce huge impact forces on structures, causing structural damage or even failures. Most existing design codes do not properly account for these impact forces due to the limited understanding of the underlying physical processes and the lack of reliable empirical formulae or numerical approaches to quantifying them. This paper presents laboratory experiments to better understand the interaction between the extreme flow hydrodynamics and the hydraulic structures and uses the measured data to validate a numerical model. The model solves the two-dimensional shallow water equations using a finite volume Godunov-type scheme for the reliable simulation of complex flow hydrodynamics. New model components are developed for estimating the hydrostatic and hydrodynamic pressure to quantify the flow impact on structures. The model is applied to reproduce two selected experiment tests with different settings and satisfactory numerical results are obtained, which confirms its predictive capability. The model will therefore provide a potential tool for wider and more flexible field-scale applications.
文摘Blcod flow of the extremities was measured in 33 cases of rheumatoid arthritis and 30 ofhealthy persons by personal vascular laboratory. It was found that the values of extremity rheography in thepatients were signiticantly lower than that in the controls . Treated with blood-circiJIation-promoting and stasis-removing traditional Chinese medicine and Mailuoning(脉络宁) Injection which has a beneficial impact on an-ti-coagulation. removing embolus and activating circtJIation, tlie symptoms, signs and tlie blood flow in theextremities otthe patients with rheumatoid arthritis were markedly improved.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51761135023 & 41476075)the China Geological Survey Nanjing Center Project (Grant No. DD20170246)
文摘The tidal limit is the key interface indicating whether water levels will be affected by tidal waves, which is of great significance to navigation safety and regional flood control. Due to limitations in research methods, recent changes in the Yangtze River tidal limit, caused by sea level rise and large-scale engineering projects, urgently need to be studied. In this study,spectrum analysis was undertaken on measured water level data from downstream Yangtze River hydrological stations from2007 to 2016. The bounds of the tidal limit were identified through comparisons between the spectra and red noise curves, and the fluctuation range and characteristics were summarized. The results showed that:(1) During the extremely dry period, when the flow rate at Jiujiang station was about 8440 m3 s-1, the tidal limit was near Jiujiang; whereas during the flood season, when the flow rate at Jiujiang station was about 66700 m3 s-1, the tidal limit was between Zongyang Sluice and Chikou station.(2)From the upper to lower reach, the effect of the Jiujiang flow rate on the tidal limit weakens, while the effect of the Nanjing tidal range increases. The tidal limit fluctuates under similar flow rates and tidal ranges, and the fluctuation range increases with increasing flow rate and decreasing tidal range.(3) With the continued influence of rising sea levels and construction in river basin estuaries, the tidal limit may move further upstream.
