Laminar Flow Past Colinear Spheres With Fluid Injection

Abstract

A validated computer simulation model has been developed for the analysis and design of colinear porous sphere systems in a convective stream. Using a modified and extended finite element software package, the steady-state Navier-Stokes equations have been solved describing laminar axisymmetric flow past closely spaced monodisperse spheres with fluid injection. Of interest are the coupled nonlinear interaction effects on the fluid flow patterns and ultimately on the drag coefficient of each sphere for different free stream Reynolds numbers (20 ≤ Re ≤ 200) and intersphere spacings (1.5 ≤ dij ≤ 6.0) in the presence of fluid injection (0 ≤ vb ≤ 0.1). At small spacings and low Reynolds numbers, fluid injection causes earlier flow separation while for Re ≥ 100 surface blowing is more influential in altering the recirculation zones between spheres and thickening the boundary layers. As a result, the total drag of each sphere decreases with increasing blowing intensity although the pressure or form drag of the first sphere may increase at small spacings.