The vortex interference mechanism on low Reynolds number between the canard and main wing of the canard-forward sweep wing （Canard-FSW） configurations is simulated numerically by employing the numerical wind tunnel ...The vortex interference mechanism on low Reynolds number between the canard and main wing of the canard-forward sweep wing （Canard-FSW） configurations is simulated numerically by employing the numerical wind tunnel method. The variations of aerodynamic characteristics of Canard-FSW configurations with different positions of the canard are investigated,finding that the aerodynamic interference and mutual coupling effect between the canard and main wing have made great contributions to the lift and stability characteristics of the whole aircraft. Canard can radically improve the surface flow pattern of the main wing. And its own vortex can have a favorable interference on the main wing and can effectively control the airflow boundary layer separation. At small angles of attack,the aerodynamic characteristics are sensitive to the positions of the canard and the main wing,but at high angles of attack,the aerodynamic performances of the configuration are not only related to the shape of the canard （forward or backward）,but also with the size of control force as well as the features of the vortices generated above the main wing and the canard. The different configurations and vortices are illustrated using the velocity vector,streamlines and pressure contours.展开更多
With Zunyi CINRAD/CD Doppler radar data and other data,a hail wind and heavy rainfall in short time occurred on July 10,2008 in northern Guizhou Province was analyzed in this study.The results showed that the system w...With Zunyi CINRAD/CD Doppler radar data and other data,a hail wind and heavy rainfall in short time occurred on July 10,2008 in northern Guizhou Province was analyzed in this study.The results showed that the system was affected by the southward of cold air pressure in a low-shear vortex zone.Echo monomer initially developed and arranged along the shear line,and there was hail weather in echo location with intense development.Before the hail shooting,the strongest echo value was 60-65 dBz.When the hail shooting,the low-elevation echo intensity sharply increased to 55-60 dBz with echo height of 11-15 km and VIL values>35 kg/m2,and its echo distribution showed band characteristics of vortex.When the vortex center moved to the original echo,echo intensity increased,resulting in a profound and lasting convergence of cyclones,and hail or strong wind occurred on the ground.Hail and strong short-term precipitation in towns of northern Renhuai might be related to the left inverted U-terrain.Echoes from Yongxing and Yuquan in Meitan,Xuekong and Xitou in Renhuai were the supercell echoes,and other regional hail shooting echoes were strong multi-monomer echoes.展开更多
By using the monthly mean grid data of NCAR/NCEP reanalysis at 500 hPa geopotential height from 1958 to 1997,the relationship between the Northeast cold vortex and the western Pacific subtropical high was analyzed.The...By using the monthly mean grid data of NCAR/NCEP reanalysis at 500 hPa geopotential height from 1958 to 1997,the relationship between the Northeast cold vortex and the western Pacific subtropical high was analyzed.The influence of the sea surface temperature(SST) and outgoing longwave radiation(OLR) on the Northeast cold vortex and subtropical high was studied.As was shown in the results,in summer,there was a positive correlation between the Northeast cold vortex and the subtropical high,and an anti-phase relationship existed between the threshold characteristic line of GMS-SST=28 ℃ and the height index of the Northeast cold vortex and the subtropical high.With the gradual northward moving of the threshold characteristic line,the subtropical high was weakening,and the Northeast cold vortex was increasing and strengthening.展开更多
基金National Defense Basic Research Program (B222006060)
文摘The vortex interference mechanism on low Reynolds number between the canard and main wing of the canard-forward sweep wing （Canard-FSW） configurations is simulated numerically by employing the numerical wind tunnel method. The variations of aerodynamic characteristics of Canard-FSW configurations with different positions of the canard are investigated,finding that the aerodynamic interference and mutual coupling effect between the canard and main wing have made great contributions to the lift and stability characteristics of the whole aircraft. Canard can radically improve the surface flow pattern of the main wing. And its own vortex can have a favorable interference on the main wing and can effectively control the airflow boundary layer separation. At small angles of attack,the aerodynamic characteristics are sensitive to the positions of the canard and the main wing,but at high angles of attack,the aerodynamic performances of the configuration are not only related to the shape of the canard （forward or backward）,but also with the size of control force as well as the features of the vortices generated above the main wing and the canard. The different configurations and vortices are illustrated using the velocity vector,streamlines and pressure contours.
文摘With Zunyi CINRAD/CD Doppler radar data and other data,a hail wind and heavy rainfall in short time occurred on July 10,2008 in northern Guizhou Province was analyzed in this study.The results showed that the system was affected by the southward of cold air pressure in a low-shear vortex zone.Echo monomer initially developed and arranged along the shear line,and there was hail weather in echo location with intense development.Before the hail shooting,the strongest echo value was 60-65 dBz.When the hail shooting,the low-elevation echo intensity sharply increased to 55-60 dBz with echo height of 11-15 km and VIL values>35 kg/m2,and its echo distribution showed band characteristics of vortex.When the vortex center moved to the original echo,echo intensity increased,resulting in a profound and lasting convergence of cyclones,and hail or strong wind occurred on the ground.Hail and strong short-term precipitation in towns of northern Renhuai might be related to the left inverted U-terrain.Echoes from Yongxing and Yuquan in Meitan,Xuekong and Xitou in Renhuai were the supercell echoes,and other regional hail shooting echoes were strong multi-monomer echoes.
文摘By using the monthly mean grid data of NCAR/NCEP reanalysis at 500 hPa geopotential height from 1958 to 1997,the relationship between the Northeast cold vortex and the western Pacific subtropical high was analyzed.The influence of the sea surface temperature(SST) and outgoing longwave radiation(OLR) on the Northeast cold vortex and subtropical high was studied.As was shown in the results,in summer,there was a positive correlation between the Northeast cold vortex and the subtropical high,and an anti-phase relationship existed between the threshold characteristic line of GMS-SST=28 ℃ and the height index of the Northeast cold vortex and the subtropical high.With the gradual northward moving of the threshold characteristic line,the subtropical high was weakening,and the Northeast cold vortex was increasing and strengthening.
