Vortex shedding suppression in mixed convective flow past a square cylinder subjected to large-scale heating using a non-Boussinesq model

Abstract

In the present work, numerical simulations are performed to investigate the vortex shedding suppression phenomenon for mixed convective flows past a square cylinder in the large-scale heating regime. A full compressible flow model with variable transport and thermo-physical properties is employed to capture large-scale heating effects. The Reynolds number, Prandtl number, and Mach number are kept constant at Re = 100, Pr = 0.71, and M = 0.1, while the cylinder inclination (ϕ), free-stream inclination (α), and over-heat ratio (ϵ) are varied in the range [0, 45°], [0, 90°], and [0, 2], respectively. The governing equations are solved numerically using the particle velocity upwind (PVU-M+) scheme. The buoyancy parameter which governs the vortex shedding suppression process in the non-Boussinesq model is identified as RiNB=ϵFr222+ϵ, where Fr is the Froude number. Using the Stuart-Landau model, the neutral curves separating the steady and unsteady flow regimes are generated in the ϵ–ϕ and ϵ–α parametric spaces. The neutral curves show qualitatively similar characteristics as observed for Boussinesq models. The relative contribution of various large-scale heating effects in suppression of vortex shedding is also highlighted. This reveals that buoyancy effects followed by variations in transport properties play a major role in suppression of vortex shedding. The findings are also applicable to a range of low Re (O(100)) as supported by data obtained at Re = 130 for ϕ = 40°. The mechanism of vortex shedding suppression has been analyzed and extended for the large-scale heating scenarios.

Near-wall effect on flow around an elliptic cylinder translating above a plane wall

“…Wakes behind other bluff bodies such as square 12,13 and elliptic cylinders have been investigated due to the practical impact on submarines 14 and heat exchangers. 15 For elliptic cylinders, the flow depends on both the aspect ratio (AR) of the elliptic cylinder (defined by the ratio of the semi-minor to semi-major axis length) and the incident angle (defined by the angle between the inlet flow direction and the semi-minor axis) in addition to the Reynolds number based on the free-stream velocity and the semi-major axis length.…”

Numerical Simulation of Heat Transfer from Three-dimensional Model of Human Head in Different Environmental Conditions

“…Since three-dimensional flow around the human head is similar to the flow around the bluff bodies, it is important to consider the previous investigations who considered heat transfer and fluid flow past the bluff bodies or vortex generators [5,[7][8][9][10][11][12]. For example, Arif and Hasan [7] studied the flow around a square cylinder and analyzed the vortex shedding phenomena considering effective parameters. Bayareh et al [12] investigated the effect of vortex generator on heat transfer of a flat plate and demonstrated that as the angle of vortex generator increases, the longitudinal vortices become stronger.…”