Stability analysis of thermo-bioconvection of oxytactic microorganisms in Newtonian fluids-saturated porous media

• Main Authors: Szu-Yen Wu, 吳思諺
• Other Authors: Long-Jye Sheu
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/46449268871041301757

碩士 === 中華大學 === 機械工程學系碩士班 === 96 === This thesis investigates the thermo-bioconvection of oxytactic microorganisms in Newtonian fluids-saturated porous media. The modified Darcy model and Boussinesq approximation is utilized in the momentum equation. A local non-equilibrium model is applied by using two equations to separately describe the temperature distributions of solid and liquid phases in the porous media. The motile velocity of microorganisms is assumed to be proportional to the gradient of oxygen concentrations. Consumption rates of oxygen by oxytactic microorganisms are also taken into account for the concentration of oxygen. A MATLAB subroutine (eig) is used to solve the eigenvalue problem to derive the critical bioconvection Rayleigh number and critical wavenumber. The stability of the thermo-bioconvective flow are discussed in terms of several dimensionless parameters such as Pelect number, the inter-phase heat transfer coefficient, the ratio of the rate of oxytaxis consumption to the rate of diffusion, the concentration diffusivity ratio and the porosity-modified conductivity ratio. Results indicate there is a critical Pelect number (about 1) to the thermo-bioconvection in porous media. The interface heat transfer (H), the Pelect number (Pe) and the ratio of the rate of oxygen consumption to the rate diffusion (β) indeed influences the stability of thermo-bioconvection.