An improved understanding and forecast of tropical cyclone intensity changes requires in part a better diagnosis of their internal dynamics.Recent contributions notably relate the evolution of maximum tangential winds...An improved understanding and forecast of tropical cyclone intensity changes requires in part a better diagnosis of their internal dynamics.Recent contributions notably relate the evolution of maximum tangential winds to the relative changes in eyewall and boundary layer mass fluxes.The present work investigates the interaction between the boundary layer inflow,eyewall convection and maximum wind evolution using realistic,high-resolution numerical simulations with a full-physics flow configuration.An in-depth analysis of a two-weeks long simulation of Hurricane Irma(2017)shows that intensification occurs when the increase of the boundary layer inflow is met with a concurrently increasing upward mass flux in the eyewall.Conversely,maturity and decay exhibit a gradual decline of this eyewall upward mass flux,and the subsequent generation of outflow above the boundary layer near the eyewall.Novel diagnostic variables are designed to quantify the upward mass flux ascending out of the boundary layer,and the fraction of this mass flux successfully ventilated to the upper troposphere by the eyewall convection.The joint evolution of these two quantities is shown to go with intensity changes,consistently over the eight simulations.The virtuous cooperation between an increasing boundary layer inflow and a positive mass flux ventilation in the eyewall is systemically associated with intensification,while the opposite detrimental cooperation characterizes intensity decays.A minority but notable amount of simulated life cycle phases show conflicting boundary layer and eyewall ventilation dynamics,and depart from the classical axisymmetric vortex model that conditions intensification on the import of cyclonic absolute vorticity above the boundary layer.These cases exhibit different pathways of intensification or decay,but remain constrained by the classical model,in part due to their inherently transient nature.This study highlights the importance of considering the eyewall ventilation along with boundary layer dynamics to diagnose the intensity variations of tropical cyclones.展开更多
Interpretation course aims to help students understand interpreting theories and master interpreting skills.Limited class hours make it difficult to achieve the expected goals.This paper therefore focuses on interpret...Interpretation course aims to help students understand interpreting theories and master interpreting skills.Limited class hours make it difficult to achieve the expected goals.This paper therefore focuses on interpretation teaching and discusses the possible ways to make teaching more effective in the limited class hours.展开更多
Facility layout problem(FLP)contemplates the optimization of space utilization,costs,and material flow.Commercial simulation softwares are commonly used to validate layouts by simulating the real world material flow a...Facility layout problem(FLP)contemplates the optimization of space utilization,costs,and material flow.Commercial simulation softwares are commonly used to validate layouts by simulating the real world material flow and production process.To validate a layout scenario of a solar module assembly workshop,a 3D simulation model is presented which was designed on VisualComponents software.To begin with,we introduce the layout characteristics and use the systematic layout planning(SLP)method to design the block layout of workshop.Then,we built components library which contains all the facilities needed in the production line,specifically conveyors,processing equipments,robots,buffers.Finally,we have established a simulation layout model using the components in the customized library according to the block layout,and configured the components which were allocated in the layout by setting the parameters and building the connection between components via signal.To improve the performance of the workshop,we have found the best work-in-process(WIP)value for the workshop and the optimal number of workers.Additionally,the layout model was used to test collision and reachability.It demonstrated the production process in a realistic simulation environment which helped in the sales process as well.The reusable component models we have built make it easy to build a layout within a short time and validate the effectiveness of the layout scenarios for any other projects.展开更多
Facility layout problem(FLP)contemplates the optimization of space utilization,costs,and material flow.Commercial simulation softwares are commonly used to validate layouts by simulating the real world material flow a...Facility layout problem(FLP)contemplates the optimization of space utilization,costs,and material flow.Commercial simulation softwares are commonly used to validate layouts by simulating the real world material flow and production process.To validate a layout scenario of a solar module assembly workshop,a 3D simulation model is presented which was designed on VisualComponents software.To begin with,we introduce the layout characteristics and use the systematic layout planning(SLP)method to design the block layout of workshop.Then,we built components library which contains all the facilities needed in the production line,specifically conveyors,processing equipments,robots,buffers.Finally,we have established a simulation layout model using the components in the customized library according to the block layout,and configured the components which were allocated in the layout by setting the parameters and building the connection between components via signal.To improve the performance of the workshop,we have found the best work-in-process(WIP)value for the workshop and the optimal number of workers.Additionally,the layout model was used to test collision and reachability.It demonstrated the production process in a realistic simulation environment which helped in the sales process as well.The reusable component models we have built make it easy to build a layout within a short time and validate the effectiveness of the layout scenarios for any other projects.展开更多
文摘An improved understanding and forecast of tropical cyclone intensity changes requires in part a better diagnosis of their internal dynamics.Recent contributions notably relate the evolution of maximum tangential winds to the relative changes in eyewall and boundary layer mass fluxes.The present work investigates the interaction between the boundary layer inflow,eyewall convection and maximum wind evolution using realistic,high-resolution numerical simulations with a full-physics flow configuration.An in-depth analysis of a two-weeks long simulation of Hurricane Irma(2017)shows that intensification occurs when the increase of the boundary layer inflow is met with a concurrently increasing upward mass flux in the eyewall.Conversely,maturity and decay exhibit a gradual decline of this eyewall upward mass flux,and the subsequent generation of outflow above the boundary layer near the eyewall.Novel diagnostic variables are designed to quantify the upward mass flux ascending out of the boundary layer,and the fraction of this mass flux successfully ventilated to the upper troposphere by the eyewall convection.The joint evolution of these two quantities is shown to go with intensity changes,consistently over the eight simulations.The virtuous cooperation between an increasing boundary layer inflow and a positive mass flux ventilation in the eyewall is systemically associated with intensification,while the opposite detrimental cooperation characterizes intensity decays.A minority but notable amount of simulated life cycle phases show conflicting boundary layer and eyewall ventilation dynamics,and depart from the classical axisymmetric vortex model that conditions intensification on the import of cyclonic absolute vorticity above the boundary layer.These cases exhibit different pathways of intensification or decay,but remain constrained by the classical model,in part due to their inherently transient nature.This study highlights the importance of considering the eyewall ventilation along with boundary layer dynamics to diagnose the intensity variations of tropical cyclones.
文摘Interpretation course aims to help students understand interpreting theories and master interpreting skills.Limited class hours make it difficult to achieve the expected goals.This paper therefore focuses on interpretation teaching and discusses the possible ways to make teaching more effective in the limited class hours.
基金the Provincial Key Technology Research and Innovation Program(3001-042097)for financial support,technician Liu Huan in the affiliation of VisualComponents for giving guidance on the software,technician Yuan Xiaoming in Yingkou Jinchen Machinery Co.,Ltd.for model simplification,and Sitara Aziz for spelling and grammar check.
文摘Facility layout problem(FLP)contemplates the optimization of space utilization,costs,and material flow.Commercial simulation softwares are commonly used to validate layouts by simulating the real world material flow and production process.To validate a layout scenario of a solar module assembly workshop,a 3D simulation model is presented which was designed on VisualComponents software.To begin with,we introduce the layout characteristics and use the systematic layout planning(SLP)method to design the block layout of workshop.Then,we built components library which contains all the facilities needed in the production line,specifically conveyors,processing equipments,robots,buffers.Finally,we have established a simulation layout model using the components in the customized library according to the block layout,and configured the components which were allocated in the layout by setting the parameters and building the connection between components via signal.To improve the performance of the workshop,we have found the best work-in-process(WIP)value for the workshop and the optimal number of workers.Additionally,the layout model was used to test collision and reachability.It demonstrated the production process in a realistic simulation environment which helped in the sales process as well.The reusable component models we have built make it easy to build a layout within a short time and validate the effectiveness of the layout scenarios for any other projects.
基金the Provincial Key Technology Research and Innovation Program(3001-042097)for financial support,technician Liu Huan in the affiliation of VisualComponents for giving guidance on the software,technician Yuan Xiaoming in Yingkou Jinchen Machinery Co.,Ltd.for model simplification,and Sitara Aziz for spelling and grammar check.
文摘Facility layout problem(FLP)contemplates the optimization of space utilization,costs,and material flow.Commercial simulation softwares are commonly used to validate layouts by simulating the real world material flow and production process.To validate a layout scenario of a solar module assembly workshop,a 3D simulation model is presented which was designed on VisualComponents software.To begin with,we introduce the layout characteristics and use the systematic layout planning(SLP)method to design the block layout of workshop.Then,we built components library which contains all the facilities needed in the production line,specifically conveyors,processing equipments,robots,buffers.Finally,we have established a simulation layout model using the components in the customized library according to the block layout,and configured the components which were allocated in the layout by setting the parameters and building the connection between components via signal.To improve the performance of the workshop,we have found the best work-in-process(WIP)value for the workshop and the optimal number of workers.Additionally,the layout model was used to test collision and reachability.It demonstrated the production process in a realistic simulation environment which helped in the sales process as well.The reusable component models we have built make it easy to build a layout within a short time and validate the effectiveness of the layout scenarios for any other projects.
