The electroosmotic flow of a micropolar fluid in a microchannel bounded by two parallel porous plates undergoing periodic vibration is studied. The equations for conservation of linear and angular momentums and Gauss...The electroosmotic flow of a micropolar fluid in a microchannel bounded by two parallel porous plates undergoing periodic vibration is studied. The equations for conservation of linear and angular momentums and Gauss＇s law of charge distribution are solved within the framework of the Debye-Hückel approximation. The fluid velocity and microrotation are assumed to depend linearly on the Reynolds number. The study shows that the amplitude of microrotation is highly sensitive to the changes in the magnitude of the suction velocity and the width of the microchannel. An increase in the micropolar parameter gives rise to a decrease in the amplitude of microrotation. Numerical estimates reveal that the microrotation of the suspended microelements in blood also plays an important role in controlling the electro-osmotically actuated flow dynamics in microbio-fluidic devices.展开更多
A fuzzy, c-means(FCM) clustering technique is explored to investigate the track of tropical cyclones over the North Indian Ocean(NIO) for the period(1976-2014). A total of fi ve clusters is objectively identifi ed bas...A fuzzy, c-means(FCM) clustering technique is explored to investigate the track of tropical cyclones over the North Indian Ocean(NIO) for the period(1976-2014). A total of fi ve clusters is objectively identifi ed based on partition index,partition coeffi cient, Dunn Index and separation index. The results obtained during analysis emphasized that each cluster has the unique features in terms of their genesis location, landfall, travel duration, trajectory, seasonality, accumulated cyclone energy and Intensity. Analysis of large scale environmental parameters, constructed preceding day of genesis show some of these parameters to be potential precursors to TC formation for almost all the clusters, most prominently, mid-tropospheric humidity, zonal wind,vorticity and outgoing long wave radiation of the main developing regions. The individual clusters have the several distinct features in their seasonal cycles.The cluster C5 shows distinct bimodal distributions where as other clusters are formed throughout the year. ENSO infl uenced the cyclone frequency in two of the fi ve clusters. The MJO is found to play an important role in the genesis of the cyclone. The post monsoon season cyclone frequency is more in MJO phase 2, 3 and 4. The technique(FCM) can be used as a guideline in terms of the probable affected zone of TC Tracks by the operational forecasters.展开更多
The track of tropical cyclone‘Madi’showed almost 180° turn around,while immediately after recurvature it decayed rapidly in the following 24 hours.Sea surface temperature(SST)analyses rule out confrontation wit...The track of tropical cyclone‘Madi’showed almost 180° turn around,while immediately after recurvature it decayed rapidly in the following 24 hours.Sea surface temperature(SST)analyses rule out confrontation with low SST as cause of weakening.At 0000 UTC of 9 December 2013 diabatic heating(DH),potential vorticity(PV)and vertical wind shear(VWS)were favourable for intensification.However,a dry area close to the system centre at mid-troposphere subsequently engulfed the middle strata and the mid-tropospheric relative humidity(MTH)drastically reduced on 0000 UTC of 10 December 2013.The MTH further reduced on 0000 UTC of 11 December 2013.Lack of moisture in mid-troposphere apparently caused a mutation within the structure causing a sudden decrease in elevation.As the system dried up,reduction in convection above 400 h Pa hindered latent heat release.PV above 400 h Pa decreased significantly.Eventually,there was a spurt of VWS at 1200 UTC of the 10December 2013.The opposite wind flow between lower level and upper level whisked away the top of the system to northeast.Under the influence of the net northeasterly flow in lower to middle troposphere,the miniature vortex recurved southwestward and the vertical distortion due to shear weakened the system into a depression.展开更多
文摘The electroosmotic flow of a micropolar fluid in a microchannel bounded by two parallel porous plates undergoing periodic vibration is studied. The equations for conservation of linear and angular momentums and Gauss＇s law of charge distribution are solved within the framework of the Debye-Hückel approximation. The fluid velocity and microrotation are assumed to depend linearly on the Reynolds number. The study shows that the amplitude of microrotation is highly sensitive to the changes in the magnitude of the suction velocity and the width of the microchannel. An increase in the micropolar parameter gives rise to a decrease in the amplitude of microrotation. Numerical estimates reveal that the microrotation of the suspended microelements in blood also plays an important role in controlling the electro-osmotically actuated flow dynamics in microbio-fluidic devices.
文摘A fuzzy, c-means(FCM) clustering technique is explored to investigate the track of tropical cyclones over the North Indian Ocean(NIO) for the period(1976-2014). A total of fi ve clusters is objectively identifi ed based on partition index,partition coeffi cient, Dunn Index and separation index. The results obtained during analysis emphasized that each cluster has the unique features in terms of their genesis location, landfall, travel duration, trajectory, seasonality, accumulated cyclone energy and Intensity. Analysis of large scale environmental parameters, constructed preceding day of genesis show some of these parameters to be potential precursors to TC formation for almost all the clusters, most prominently, mid-tropospheric humidity, zonal wind,vorticity and outgoing long wave radiation of the main developing regions. The individual clusters have the several distinct features in their seasonal cycles.The cluster C5 shows distinct bimodal distributions where as other clusters are formed throughout the year. ENSO infl uenced the cyclone frequency in two of the fi ve clusters. The MJO is found to play an important role in the genesis of the cyclone. The post monsoon season cyclone frequency is more in MJO phase 2, 3 and 4. The technique(FCM) can be used as a guideline in terms of the probable affected zone of TC Tracks by the operational forecasters.
文摘The track of tropical cyclone‘Madi’showed almost 180° turn around,while immediately after recurvature it decayed rapidly in the following 24 hours.Sea surface temperature(SST)analyses rule out confrontation with low SST as cause of weakening.At 0000 UTC of 9 December 2013 diabatic heating(DH),potential vorticity(PV)and vertical wind shear(VWS)were favourable for intensification.However,a dry area close to the system centre at mid-troposphere subsequently engulfed the middle strata and the mid-tropospheric relative humidity(MTH)drastically reduced on 0000 UTC of 10 December 2013.The MTH further reduced on 0000 UTC of 11 December 2013.Lack of moisture in mid-troposphere apparently caused a mutation within the structure causing a sudden decrease in elevation.As the system dried up,reduction in convection above 400 h Pa hindered latent heat release.PV above 400 h Pa decreased significantly.Eventually,there was a spurt of VWS at 1200 UTC of the 10December 2013.The opposite wind flow between lower level and upper level whisked away the top of the system to northeast.Under the influence of the net northeasterly flow in lower to middle troposphere,the miniature vortex recurved southwestward and the vertical distortion due to shear weakened the system into a depression.
