@article{geng_kuznetsov_2007, title={Dynamics of large solid particles in bioconvective sedimentation}, volume={53}, ISSN={["1097-0363"]}, DOI={10.1002/fld.1301}, abstractNote={Settling of one or two large solid particles in a bioconvection flow induced by gyrotactic motile microorganisms is investigated using a 2D numerical model. The results of varying the initial positions of large particles on the bioconvection flow pattern are investigated. The Chimera method is utilized to generate subgrids around the moving particles. It is demonstrated that the introduction of a single large particle displaces bioconvection plume and changes its shape. The introduction of two particles on the same side of the bioconvection plume further displaces the plume while the introduction of two particles on opposite sides reduces this displacement. The influence of the bioconvection plume on the particles' settling paths and particles' settling velocities is investigated. Copyright © 2006 John Wiley & Sons, Ltd.}, number={5}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS}, author={Geng, P. and Kuznetsov, A. V.}, year={2007}, month={Feb}, pages={713–733} } @article{geng_kuznetsov_2006, title={Direct numerical simulation of settling of a large solid particle during bioconvection}, volume={51}, ISSN={["1097-0363"]}, DOI={10.1002/fld.1125}, abstractNote={Settling of a large solid particle in bioconvection flow caused by gyrotactic microorganisms is investigated. The particle is released from the top of the bioconvection chamber; its settling pattern depends on whether it is released in the centre of the bioconvection plume or at its periphery. The Chimera method is utilized; a subgrid is generated around a moving particle. The method suggested by Liu and Wang (Comput. Fluid 2004; 33:223-255) is further developed to account for the presence of a moving boundary in the streamfunction-vorticity formulation using the finite-difference method. A number of cases for different release positions of the particle are computed. It is demonstrated that bioconvection can either accelerate or decelerate settling of the particle depending on the initial position of the particle relative to the plume centre. It is also shown that the particle impacts bioconvection plume by changing its shape and location in the chamber.}, number={5}, journal={INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS}, author={Geng, P. and Kuznetsov, A. V.}, year={2006}, month={Jun}, pages={511–530} } @article{geng_kuznetsov_2005, title={Settling of bidispersed small solid particles in a dilute suspension containing gyrotactic micro-organisms}, volume={43}, ISSN={["1879-2197"]}, DOI={10.1016/j.ijengsci.2005.03.002}, abstractNote={The motivation of this research is to investigate the feasibility of utilizing bioconvection for enhancing mixing in a suspension of small solid particles. This may be important in micro-fluidic applications relevant to biotechnology and medicine, such as analyses of DNA or drugs, screening of patients, and combinatorial synthesis. Traditionally, the mixing of fluids in micro-volumes has been limited to diffusion. Due to the microscopic size of the organisms involved in bioconvection, bioconvective flows are a prospective and novel alternative for micro-fluidic mixing. This paper considers a bidispersed suspension of small solid particles that have different densities and settling velocities in a fluid that contains motile gyrotactic micro-organisms. The particles are assumed to be sufficiently small so that their Brownian diffusion is not negligible. It is found that the number density distribution of solid particles of one type impacts that of particles of the other type as well as that of micro-organisms.}, number={11-12}, journal={INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE}, author={Geng, P and Kuznetsov, AV}, year={2005}, month={Jul}, pages={992–1010} } @article{kuznetsov_geng_2005, title={The interaction of bioconvection caused by gyrotactic micro-organisms and settling of small solid particles}, volume={15}, DOI={10.1108/0961550510590597}, number={4}, journal={International Journal of Numerical Methods for Heat & Fluid Flow}, author={Kuznetsov, A. V. and Geng, P.}, year={2005}, pages={328–347} } @article{geng_kuznetsov_2004, title={Effect of small solid particles on the development of bioconvection plumes}, volume={31}, ISSN={["0735-1933"]}, DOI={10.1016/S0735-1933(04)00050-8}, abstractNote={We investigate numerically the impact of small solid particles on the steady-state bioconvection plume caused by up-swimming of motile gyrotactic micro-organisms. Small solid particles that are heavier than water are added into the upper fluid layer when bioconvection has already attained its steady-state. As sedimentation process goes on, solid particles get involved in convection. They impact the fluid flow and cause the transition of the bioconvection plume to a different steady-state}, number={5}, journal={INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER}, author={Geng, P and Kuznetsov, AV}, year={2004}, month={Jul}, pages={629–638} }