Trihybrid Nanofluid Flow under Thermal Radiation with Cattaneo–Christov Heat Flux: Oxytaxis and Gyrotaxis Effects in a Porous Medium with Surface Roughness

Abstract

In the present study, mathematical modeling of trihybrid nanofluid flow under the influence of thermal radiation and Cattaneo–Christov heat flux in a porous medium with surface roughness is investigated. The model incorporates the bioconvective behavior of microorganisms, characterized by oxytaxis and gyrotaxis effects. The trihybrid nanofluid comprising three distinct nanoparticles dispersed in a base fluid significantly enhances the thermal transport properties. The governing nonlinear partial differential equations describing momentum, energy, nanoparticle concentration, and microorganism density are transformed into a system of ordinary differential equations using similarity transformations. Thermal radiation and porous medium resistance are included through the Rosseland approximation and Darcy–Brinkman formulation, respectively. Surface roughness is incorporated through modified boundary conditions that affect the velocity gradients. The resulting equations are solved numerically using the Runge–Kutta–Fehlberg shooting technique. The effects of various physical parameters, such as the radiation parameter, Cattaneo–Christov relaxation time, nanoparticle volume fraction, porosity parameter, oxytaxis parameter, and gyrotactic parameter, on the velocity, temperature, concentration, and microorganism profiles are analyzed. The results demonstrate that thermal radiation enhances heat transfer, whereas Cattaneo–Christov relaxation suppresses thermal diffusion. The presence of oxytactic microorganisms significantly alters the stability of the bioconvective flow. The model provides insights into advanced thermal systems, such as biomedical devices, solar collectors, microfluidic systems, and porous heat exchangers.