Abstract
Cross flow of oxytactic microorganisms under the action of Lorentz force is examined in this study past a porous Riga surface. Rheological Couple stress nano fluid model is considered as working fluid model. The leading equations of governed problem are expressed with aid of non-dimensional parameters and solved numerically by shooting method. The numerical solution of governed problem is presented in forms of graphs and tables. Velocity of fluid, temperature of fluid, concentration of fluid, and volume fraction of gyrotactic microorganisms are portrayed through graphs. Physical magnitudes including surface skin friction, local heat and mass flux surface are computed and presented in the form of graph. Heat flux rises while mass flux decreases with couple stress parameter. Local motile density rises with couple stress parameter while it decreases with thermopherosis parameter.