The three-dimensional lattice Boltzmann method(LBM)is used to simulate the motion of a spherical squirmer in a square tube,and the steady motion velocity of a squirmer with different Reynolds numbers(Re,ranging from 0...The three-dimensional lattice Boltzmann method(LBM)is used to simulate the motion of a spherical squirmer in a square tube,and the steady motion velocity of a squirmer with different Reynolds numbers(Re,ranging from 0.1 to 2)and swimming types is investigated and analyzed to better understand the swimming characteristics of microorganisms in different environments.First,as the Reynolds number increases,the effect of the inertial forces becomes significant,disrupting the squirmer's ability to maintain its theoretical velocity.Specifically,as the Reynolds number increases,the structure of the flow field around the squirmer changes,affecting its velocity of motion.Notably,the swimming velocity of the squirmer exhibits a quadratic relationship with the type of swimming and the Reynolds number.Second,the narrow tube exerts a significant inhibitory effect on the squirmer motion.In addition,although chirality does not directly affect the swimming velocity of the squirmer,it can indirectly affect the velocity by changing its motion mode.展开更多
This study employs the fluctuating-lattice Boltzmann method to investigate temperaturegradient-driven aggregation of microswimmers,specifically,pulling-type(pullers)and pushing-type(pushers),within a fluid confined by...This study employs the fluctuating-lattice Boltzmann method to investigate temperaturegradient-driven aggregation of microswimmers,specifically,pulling-type(pullers)and pushing-type(pushers),within a fluid confined by two channel walls.The analysis incorporates the Brownian motion of both swimmer types and introduces key dimensionless parameters,including the swimming Reynolds,Prandtl,and Lewis numbers,to characterize the influences of self-propulsion strength,thermal diffusivity,and Brownian diffusivity on aggregation efficiency and behavior.Our findings reveal that pushers tend to aggregate either along the channel centerline or near the channel walls under conditions of thermal gradients imposed by heated or cooled boundaries.Notably,pushers can be focused on the channel walls even under minimal temperature differences.In contrast,pullers exhibit sensitivity primarily to heated walls,a phenomenon for which a plausible explanation is proposed.Further analysis identifies the swimming Reynolds number as a critical determinant of aggregation efficiency and performance for both pullers and pushers.Additionally,the Prandtl number predominantly governs aggregation efficiency,while the Lewis number chiefly influences aggregation performance.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.12132015 and 12372251)the Fundamental Research Funds for the Provincial Universities of Zhejiang of China(No.2023YW69)。
文摘The three-dimensional lattice Boltzmann method(LBM)is used to simulate the motion of a spherical squirmer in a square tube,and the steady motion velocity of a squirmer with different Reynolds numbers(Re,ranging from 0.1 to 2)and swimming types is investigated and analyzed to better understand the swimming characteristics of microorganisms in different environments.First,as the Reynolds number increases,the effect of the inertial forces becomes significant,disrupting the squirmer's ability to maintain its theoretical velocity.Specifically,as the Reynolds number increases,the structure of the flow field around the squirmer changes,affecting its velocity of motion.Notably,the swimming velocity of the squirmer exhibits a quadratic relationship with the type of swimming and the Reynolds number.Second,the narrow tube exerts a significant inhibitory effect on the squirmer motion.In addition,although chirality does not directly affect the swimming velocity of the squirmer,it can indirectly affect the velocity by changing its motion mode.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12372251 and 12132015).
文摘This study employs the fluctuating-lattice Boltzmann method to investigate temperaturegradient-driven aggregation of microswimmers,specifically,pulling-type(pullers)and pushing-type(pushers),within a fluid confined by two channel walls.The analysis incorporates the Brownian motion of both swimmer types and introduces key dimensionless parameters,including the swimming Reynolds,Prandtl,and Lewis numbers,to characterize the influences of self-propulsion strength,thermal diffusivity,and Brownian diffusivity on aggregation efficiency and behavior.Our findings reveal that pushers tend to aggregate either along the channel centerline or near the channel walls under conditions of thermal gradients imposed by heated or cooled boundaries.Notably,pushers can be focused on the channel walls even under minimal temperature differences.In contrast,pullers exhibit sensitivity primarily to heated walls,a phenomenon for which a plausible explanation is proposed.Further analysis identifies the swimming Reynolds number as a critical determinant of aggregation efficiency and performance for both pullers and pushers.Additionally,the Prandtl number predominantly governs aggregation efficiency,while the Lewis number chiefly influences aggregation performance.
