Rheological effects of micropolar slime on the gliding motility of bacteria with slip boundary condition

The gliding organisms are phylogenetically diverse with their hundreds of types, different shapes and several mechanism of motility. Gliding bacteria are rod-shaped bacteria without any flagella on their surface. They exhibit a creeping type of self-powered motion when nearly in contact with a solid surface. These bacteria leave an adhesive trail of slime and propel themselves by producing undulating waves in their body, which is one possible mode of motility for gliding bacteria. In the present study an undulating surface model is considered to discuss this type of bacterial locomotion. The classical Navier-Stokes equations are incapable of explaining the slime rheology at the microscopic level. Micropolar fluid dynamics however provides a solid framework for mimicking bacterial physical phenomena at both micro and nano-scales, and therefore in the present study, the constitutive equations of micropolar fluid are implemented to characterize the rheology of the slime. The flow equations are formulated under long wavelength and low Reynolds number assumptions. Exact expressions for stream function and pressure gradient are obtained. The speed of the gliding bacteria is numerically calculated by using a modified Newton-Raphson method. In addition, when the glider is fixed, the effects of micropolar slime parameters on the velocity, micro-rotation (angular velocity) of spherical slime particles, pressure rise per wavelength, pumping and trapping phenomena are also shown graphically and discussed in detail. The study is relevant to emerging biofuel cell technologies and also bacterial biophysics

Preliminary calculations of flow in channel with triangular and rectangular obstacle

The paper presents the results of preliminary numerical calculations of a fluid flow in a channel with an obstacle. The flow problem was solved with an application of the finite elements method. Various geometries of obstacles were considered

Solvers for Systems of Nonlinear Algebraic Equations - Their Sensitivity to Starting Vectors

In this note we compare the sensitivity of six advanced solvers for systems of nonlinear algebraic equations to the choice of starting vectors. We will report on results of our experiments in which, for each test problem, the calculated solution was used as the center from which we have moved away in various directions and observed the behavior of each solver attempting to find the solution. We are particularly interested in determining the best global starting vectors. Experimental results are presented and discussed