2013 journal article

The onset of bio-thermal convection induced by a combined effect of gyrotactic and oxytactic microorganisms

INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW, 23(6), 979–1000.

co-author countries: United States of America 🇺🇸
author keywords: Thermobioconvection; Gyrotactic and oxytactic microorganisms; Natural convection; Onset of instability; Horizontal layer; Convection; Micro-organisms
Source: Web Of Science
Added: August 6, 2018

Purpose The purpose of this paper is to investigate the stability of a suspension containing both gyrotactic and oxytactic microorganisms for the case when the suspension occupies a horizontal layer of finite depth. The lower boundary of the layer is assumed rigid while at the upper boundary both situations of rigid and stress‐free boundary conditions are considered. Design/methodology/approach Linear instability analysis is utilized, and the obtained eigenvalue problem is solved analytically using a one‐term Galerkin method. Findings The obtained eigenvalue equation relates three Rayleigh numbers, the traditional thermal Rayleigh number and two bioconvection Rayleigh numbers, for gyrotactic and oxytactic microorganisms. Research limitations/implications Only the case of non‐oscillatory instability (which always occurs when heating from the bottom is considered) is analyzed. Further experimental research is needed to elucidate possible interaction between gyrotactic and oxytactic microorganisms. The developed theory is applicable only for dilute suspensions. Originality/value This paper extends the traditional theory of bio‐thermal convection to the case when the suspension contains two types of motile microorganisms exhibiting different behaviors.