Abstract
A numerical simulation is conducted to study the laminar flow past a square cylinder confined in a channel (the ratio of side length of the square to channel width is fixed at 1/4) subjected to a locally uniform blowing/suction speed placed at the top and bottom channel walls. Governing equations with boundary conditions are resolved using a finite volume method in pressure–velocity formulation. The flow patterns relevant to the critical spacing values are investigated. Numerical results show that wall blowing has a stabilizing effect on the flow, and the corresponding critical Reynolds number increases monotonically with increasing blowing velocity. Remarkably, steady asymmetric solutions and hysteretic mode transitions exist in a certain range of parameters (Reynolds number and suction speed) in the case of suction.
Highlights
Fluid flow past a confined or unconfined square cylinder is a model problem of fundamental interest because it affects a number of practical engineering applications, such as building aerodynamics and cooling of electronics
From the relation ∝ (Re − ReH )1/2 (Mizushima and Ino 2008), the critical Reynolds number ReH beyond which the flow switches from a steady pattern to a periodic flow can be obtained by extrapolation
In order to investigate the influence of initial condition on flow pattern, we explore the hysteretic transition for all the blowing/ suction speeds when the Reynolds number is varied in two different ways, one being a progressive increase and the other a progressive decrease
Summary
Fluid flow past a confined or unconfined square cylinder is a model problem of fundamental interest because it affects a number of practical engineering applications, such as building aerodynamics and cooling of electronics. 2D incompressible flow past a cylinder is known to be steady, laminar, and symmetric at sufficiently low flow rates. This steady flow loses stability at a critical Reynolds number beyond which vortices are formed and shed alternately behind the cylinder, thereby causing a periodic flow in its wake region. This periodic vortex street causes fluctuating lift and drag forces, which are major factors in most flow systems in engineering and industrial applications, e.g., deterioration of vehicle performance and fatigue of mechanical structures. Suction/blowing method, one of the most effective active flow-control methods, has been widely used in many aspects, such as bluff body
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
