Passive Control of Hydrodynamic Forces on a Circular Obstacle in a Transient Flow: FEM Computations

Abstract

Hydrodynamic forces are crucial in engineering applications; therefore, various research initiatives have been conducted to limit them. In this research, a passive control technique to investigate the fluid forces acting on a circular cylinder in a laminar flow regime is studied. The reliability of the usage of a splitter plate (passive control device) downstream of the obstacle in suppressing the fluid forces on a circular obstacle of diameterD=0.1is presented. The first parameter of the current study is the attachment of splitter plates of various lengths(Li)with the obstacle, whereas the gap separation(Gi)between the splitter plate and the obstacle is used as a second parameter. The control element of the first and second parameters are varied from0.1to0.3. For the attached splitter plates of lengths0.2and0.3, the oscillatory behavior of transient flow atRe=100is successfully controlled. For the gap separations0.1and0.2, the suppression of vortex shedding is also observed. However, it is observed that a splitter plate of too short length and a plate located at an inappropriate gap from an obstacle are worthless. Moreover, the present study is extended for power-law fluid in the same domain, and maximum drag reduction is achieved using the same strategy as for Newtonian fluid. The finite element method is utilized as a computational strategy for complicated nonlinear governing equations. For a clear physical depiction of the problem, velocity and pressure plots have been provided. It is concluded that the presence of a splitter plate has suppressed the vortex shedding and the flow regime turns out to be steady, as is evident from the nonoscillatory drag and lift coefficients.