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In this paper, we investigate non-Newtonian Casson fluid flow with pulsation in a channel having symmetrical constriction bumps on the upper and lower walls. The medium is assumed to be porous, following Darcy's law. The fluid is modeled as electrically low conducting, and the pulsatile flow is subjected to a transverse magnetic field of uniform strength to study the impact of the resulting Lorentz force. We transform the mathematical model using the vorticity-stream function form for obtaining the solution. We analyze influence of the Hartman, Strouhal, Casson fluid, and porosity parameters on various flow profiles. It is revealed that the region of flow separation in the wake of a constriction bump tends to vanish with increasing the magnetic field parameter as well as Casson fluid parameter. The wall shear stress has higher values at the first constriction bump than that at the second constriction bump on a wall. It is also noticed that wall shear stress decreases with increasing the value of the porosity parameter during the pulsation cycle. [ABSTRACT FROM AUTHOR]

Proper orthogonal decomposition (POD) is often employed in developing reduced-order models (ROM) in fluid flows for design, control, and optimization. Contrary to the usual practice where velocity field is the focus, we apply the POD analysis on the pressure field data obtained from numerical simulations of the flow past stationary and oscillating cylinders. Since pressure mainly contributes to the hydrodynamic forces acting on the structure, we compute the pressure POD modes on the cylinder surface oscillating in lock-in and lock-out regions. These modes are then dissected into sine and cosine magnitudes to estimate their contribution in the development of pressure lift and drag decomposition coefficients, respectively. The key finding of this study is that more POD modes are required to capture the flow physics in nonsynchronous regimes as compared to synchronization case. Engineering application of this study is the development of reduced-order models for effective control techniques. [ABSTRACT FROM AUTHOR]

The present paper examines the flow behavior and separation region of a non-Newtonian electrically conducting Casson fluid through a two-dimensional porous channel by using Darcy's law for the steady and pulsatile flows. The vorticity-stream function approach is employed for the numerical solution of the flow equations. The effects of various emerging parameters on wall shear stress and stream-wise velocity are displayed through graphs and discussed in detail. It is noticed the increasing values of the magnetic field parameter (Hartman number) cause vanishing of the flow separation region and flattening of the stream-wise velocity component. The study also reveals that the non-Newtonian character of Casson fluid bears the potential of controlling the flow separation region in both steady and pulsating flow conditions. [ABSTRACT FROM AUTHOR]