The two-step hydro-bulge forming technique was proposed to manufacture the ellipsoidal shell with the length ratio of the long axis to the short axis larger than 1.4. A central tube was introduced into the first step ...The two-step hydro-bulge forming technique was proposed to manufacture the ellipsoidal shell with the length ratio of the long axis to the short axis larger than 1.4. A central tube was introduced into the first step of the hydro-bulge forming process to constrain the over growth of the short axis during bulging,and then the central tube was replaced with two polar plates in the second step of the hydro-bulge forming process to manufacture an integral ellipsoidal shell. It is shown that the central tube restricts the growth of the short axis and simultaneously reduces the shrunk tendency of the long axis. The wrinkling occurs due to the latitudinal compressive stress at the equator at the early stage of hydro-bulge forming. However,with the increase of internal pressure,the compressive stress areas gradually decrease and finally the tensile latitudinal stress occupies approximately the whole shell,thus the wrinkles are eliminated. A sound ellipsoidal shell with the axis length ratio of 1.8 is obtained after two-step hydro bulging.展开更多
The evolution of the microphysical properties of raindrops from Typhoon Mangkhut’s outer rainbands as the storm made landfall in South China in September 2018 was investigated.The observations by three two-dimensiona...The evolution of the microphysical properties of raindrops from Typhoon Mangkhut’s outer rainbands as the storm made landfall in South China in September 2018 was investigated.The observations by three two-dimensional video disdrometers deployed in central Guangdong Province were analyzed concurrently.It was found that the radial distribution of the median volume diameter(D_(0))and normalized intercept parameter(N_(w))varied in different stages,and that raindrops smaller than 3.0 mm contributed more than 99%of the total precipitation.Considering the characteristics of precipitation in the typhoon outer rainband,a modified stratiform rain(SR)-convective rain(CR)separator line is proposed based on D_(0) and N_(w) scatterplots.Meanwhile,an“S-C likelihood index”is introduced,which was used to classify three rain types(SR,CR,and mixed rain).The CR results were highly consistent with those of the improved typhoon precipitation classification method based on rain rate.By calculating effectively the radar reflectivity factor(Ze)in the Ku and Ka bands,D0-Ze and N_(w)-D_(0) empirical relations were thereby derived for improving the accuracy of rainfall retrieval.Among the four quantitative precipitation estimators using S-band dual-polarimetric radar parameters simulated by the T-matrix method,the estimator that adopted the specific differential phase and differential reflectivity was found to be the most effective for both SR and CR.展开更多
基金Sponsored by the National Natural Science Foundation of China (Grant No. 59975022 and 50275034)
文摘The two-step hydro-bulge forming technique was proposed to manufacture the ellipsoidal shell with the length ratio of the long axis to the short axis larger than 1.4. A central tube was introduced into the first step of the hydro-bulge forming process to constrain the over growth of the short axis during bulging,and then the central tube was replaced with two polar plates in the second step of the hydro-bulge forming process to manufacture an integral ellipsoidal shell. It is shown that the central tube restricts the growth of the short axis and simultaneously reduces the shrunk tendency of the long axis. The wrinkling occurs due to the latitudinal compressive stress at the equator at the early stage of hydro-bulge forming. However,with the increase of internal pressure,the compressive stress areas gradually decrease and finally the tensile latitudinal stress occupies approximately the whole shell,thus the wrinkles are eliminated. A sound ellipsoidal shell with the axis length ratio of 1.8 is obtained after two-step hydro bulging.
基金Supported by the National Key Research and Development Program of China (2018YFC1507905)National Natural Science Foundation of China (41675136 and 41875170)+3 种基金National Undergraduate Innovation and Entrepreneurship Training Program (201910300040Z)Opening Project of Key Laboratory for Aerosol–Cloud–Precipitation of China Meteorological Administration (KDW1405)Natural Science Foundation of Guangdong Province of China-Major Basic Research and Cultivation Projects (2015A030308014)Guangxi Key Research and Development Program (AB20159013)
文摘The evolution of the microphysical properties of raindrops from Typhoon Mangkhut’s outer rainbands as the storm made landfall in South China in September 2018 was investigated.The observations by three two-dimensional video disdrometers deployed in central Guangdong Province were analyzed concurrently.It was found that the radial distribution of the median volume diameter(D_(0))and normalized intercept parameter(N_(w))varied in different stages,and that raindrops smaller than 3.0 mm contributed more than 99%of the total precipitation.Considering the characteristics of precipitation in the typhoon outer rainband,a modified stratiform rain(SR)-convective rain(CR)separator line is proposed based on D_(0) and N_(w) scatterplots.Meanwhile,an“S-C likelihood index”is introduced,which was used to classify three rain types(SR,CR,and mixed rain).The CR results were highly consistent with those of the improved typhoon precipitation classification method based on rain rate.By calculating effectively the radar reflectivity factor(Ze)in the Ku and Ka bands,D0-Ze and N_(w)-D_(0) empirical relations were thereby derived for improving the accuracy of rainfall retrieval.Among the four quantitative precipitation estimators using S-band dual-polarimetric radar parameters simulated by the T-matrix method,the estimator that adopted the specific differential phase and differential reflectivity was found to be the most effective for both SR and CR.
