The maximum entropy principle(MEP) is one of the first methods which have been used to predict droplet size and velocity distributions of liquid sprays. This method needs a mean droplets diameter as an input to predic...The maximum entropy principle(MEP) is one of the first methods which have been used to predict droplet size and velocity distributions of liquid sprays. This method needs a mean droplets diameter as an input to predict the droplet size distribution. This paper presents a new sub-model based on the deterministic aspects of liquid atomization process independent of the experimental data to provide the mean droplets diameter for using in the maximum entropy formulation(MEF). For this purpose, a theoretical model based on the approach of energy conservation law entitled energy-based model(EBM) is presented. Based on this approach, atomization occurs due to the kinetic energy loss. Prediction of the combined model(MEF/EBM) is in good agreement with the available experimental data. The energy-based model can be used as a fast and reliable enough model to obtain a good estimation of the mean droplets diameter of a spray and the combined model(MEF/EBM) can be used to well predict the droplet size distribution at the primary breakup.展开更多
Droplet impact dynamics on solid surfaces,which are ubiquitously present in aerospace engineering,energy systems,agricultural production,etc.,involve complex fluid–structure interactions.Herein,we employ a single-cam...Droplet impact dynamics on solid surfaces,which are ubiquitously present in aerospace engineering,energy systems,agricultural production,etc.,involve complex fluid–structure interactions.Herein,we employ a single-camera high-speed threedimensional digital image correlation system to quantify the full-field deformations of flexible thin films during droplet impact dynamics.Experimental results revealed that the substrate flexibility not only reduces the maximum spreading diameter by 10%but also modulates rebound dynamics via energy competition between kinetic energy and surface adhesion energy,suggesting that coupled deformation of the solid–fluid interface plays an important role in the dynamic progress.We propose the structure-coupled response number(Sn),a governing dimensionless parameter unifying droplet spreading on both rigid and flexible films,validated by a universal 1/2 scaling law.A theoretical criterion for droplet rebound on hydrophobic flexible thin films is derived and experimentally demonstrated,which achieves the precise control of droplet rebound/non-rebound mode.This work bridges the theories of droplet impact dynamics on rigid and flexible substrates,offering a robust strategy to govern the droplet impact behaviors.展开更多
The maximum diameter color-spanning set problem（MaxDCS） is defined as follows： given n points with m colors, select m points with m distinct colors such that the diameter of the set of chosen points is maximized. I...The maximum diameter color-spanning set problem（MaxDCS） is defined as follows： given n points with m colors, select m points with m distinct colors such that the diameter of the set of chosen points is maximized. In this paper, we design an optimal O（n log n） time algorithm using rotating calipers for MaxDCS in the plane. Our algorithm can also be used to solve the maximum diameter problem of imprecise points modeled as polygons. We also give an optimal algorithm for the all farthest foreign neighbor problem（AFFN） in the plane, and propose algorithms to answer the farthest foreign neighbor query（FFNQ） of colored sets in two- and three-dimensional space. Furthermore, we study the problem of computing the closest pair of color-spanning set（CPCS） in d-dimensional space, and remove the log m factor in the best known time bound if d is a constant.展开更多
文摘The maximum entropy principle(MEP) is one of the first methods which have been used to predict droplet size and velocity distributions of liquid sprays. This method needs a mean droplets diameter as an input to predict the droplet size distribution. This paper presents a new sub-model based on the deterministic aspects of liquid atomization process independent of the experimental data to provide the mean droplets diameter for using in the maximum entropy formulation(MEF). For this purpose, a theoretical model based on the approach of energy conservation law entitled energy-based model(EBM) is presented. Based on this approach, atomization occurs due to the kinetic energy loss. Prediction of the combined model(MEF/EBM) is in good agreement with the available experimental data. The energy-based model can be used as a fast and reliable enough model to obtain a good estimation of the mean droplets diameter of a spray and the combined model(MEF/EBM) can be used to well predict the droplet size distribution at the primary breakup.
基金supported by the National Key R&D Program of China(grant nos.2022YFF0503500 and 2022YFA1203200)the Guangdong Basic and Applied Basic Research Foundation(grant no.2023A1515011784)+2 种基金the National Natural Science Foundation of China(grant no.12032019)the Strategic Priority Research Program of Chinese Academy of Sciences(grant nos.XDB0620101 and XDB0620103)the Youth Innovation Promotion Association,Chinese Academy of Sciences(no.2020020).
文摘Droplet impact dynamics on solid surfaces,which are ubiquitously present in aerospace engineering,energy systems,agricultural production,etc.,involve complex fluid–structure interactions.Herein,we employ a single-camera high-speed threedimensional digital image correlation system to quantify the full-field deformations of flexible thin films during droplet impact dynamics.Experimental results revealed that the substrate flexibility not only reduces the maximum spreading diameter by 10%but also modulates rebound dynamics via energy competition between kinetic energy and surface adhesion energy,suggesting that coupled deformation of the solid–fluid interface plays an important role in the dynamic progress.We propose the structure-coupled response number(Sn),a governing dimensionless parameter unifying droplet spreading on both rigid and flexible films,validated by a universal 1/2 scaling law.A theoretical criterion for droplet rebound on hydrophobic flexible thin films is derived and experimentally demonstrated,which achieves the precise control of droplet rebound/non-rebound mode.This work bridges the theories of droplet impact dynamics on rigid and flexible substrates,offering a robust strategy to govern the droplet impact behaviors.
基金supported by the International Science and Technology Cooperation Program of China under Grant No.2010DFA92720the National Natural Science Foundation of China under Grant Nos.11271351,60928006,and 61379087
文摘The maximum diameter color-spanning set problem（MaxDCS） is defined as follows： given n points with m colors, select m points with m distinct colors such that the diameter of the set of chosen points is maximized. In this paper, we design an optimal O（n log n） time algorithm using rotating calipers for MaxDCS in the plane. Our algorithm can also be used to solve the maximum diameter problem of imprecise points modeled as polygons. We also give an optimal algorithm for the all farthest foreign neighbor problem（AFFN） in the plane, and propose algorithms to answer the farthest foreign neighbor query（FFNQ） of colored sets in two- and three-dimensional space. Furthermore, we study the problem of computing the closest pair of color-spanning set（CPCS） in d-dimensional space, and remove the log m factor in the best known time bound if d is a constant.
