This paper describes the application of a three-dimensional lattice Boltzmann method(LBM)to Newtonian and non-Newtonian(Bingham fluid in this work)flows with free surfaces.A mass tracking algorithm was incorporated to...This paper describes the application of a three-dimensional lattice Boltzmann method(LBM)to Newtonian and non-Newtonian(Bingham fluid in this work)flows with free surfaces.A mass tracking algorithm was incorporated to capture the free surface,whereas Papanastasiou's modified model was used for Bingham fluids.The lattice Boltzmann method was first validated using two benchmarks:Newtonian flow through a square cross-section tube and Bingham flow through a circular cross-section tube.Afterward,the dam-break problem for the Newtonian fluid and the slump test for Bingham fluid were simulated to validate the free-surface-capturing algorithm.The numerical results were in good agreement with analytical results,as well as other simulations,thereby proving the validity and correctness of the current method.The proposed method is a promising substitute for time-consuming and costly physical experiments to solve problems encountered in geotechnical and geological engineering,such as the surge and debris flow induced by a landslide or earthquake.展开更多
This paper considers a leader-following tracking control problem for second-order multiagent systems(MASs) under measurement noises and directed communication channels.It is assumed that each follower-agent can measur...This paper considers a leader-following tracking control problem for second-order multiagent systems(MASs) under measurement noises and directed communication channels.It is assumed that each follower-agent can measure the relative positions and velocities of its neighbors in a noisy environment.Based on a novel velocity decomposition technique,a neighbor-based control law is designed to realize local control strategies for these continuous-time agents.It is shown that the proposed consensus protocol can guarantee that all the follower-agents track the active leader.In addition,this result is extended to a more general case with switching topologies.Finally,a numerical example is given for illustration.展开更多
基金support from the Natural Science Foundation of China(Grant Nos.11272048,51239006 and 11572178)the Tsinghua University Initiative Scientific Research Program
文摘This paper describes the application of a three-dimensional lattice Boltzmann method(LBM)to Newtonian and non-Newtonian(Bingham fluid in this work)flows with free surfaces.A mass tracking algorithm was incorporated to capture the free surface,whereas Papanastasiou's modified model was used for Bingham fluids.The lattice Boltzmann method was first validated using two benchmarks:Newtonian flow through a square cross-section tube and Bingham flow through a circular cross-section tube.Afterward,the dam-break problem for the Newtonian fluid and the slump test for Bingham fluid were simulated to validate the free-surface-capturing algorithm.The numerical results were in good agreement with analytical results,as well as other simulations,thereby proving the validity and correctness of the current method.The proposed method is a promising substitute for time-consuming and costly physical experiments to solve problems encountered in geotechnical and geological engineering,such as the surge and debris flow induced by a landslide or earthquake.
基金supported by the National Natural Science Foundation of China under Grant No.61174070the Specialized Research Found for the Doctoral Program under Grant No.20110172110033
文摘This paper considers a leader-following tracking control problem for second-order multiagent systems(MASs) under measurement noises and directed communication channels.It is assumed that each follower-agent can measure the relative positions and velocities of its neighbors in a noisy environment.Based on a novel velocity decomposition technique,a neighbor-based control law is designed to realize local control strategies for these continuous-time agents.It is shown that the proposed consensus protocol can guarantee that all the follower-agents track the active leader.In addition,this result is extended to a more general case with switching topologies.Finally,a numerical example is given for illustration.
