Forced convection past a semi-circular cylinder at incidence with a downstream circular cylinder: Thermofluidic transport and stability analysis

The present study analyzes the transport characteristics and associated instability of a forced convective flow past a semi-circular cylinder at incidence with a downstream circular cylinder. Considering air as an operating fluid, unsteady computations are performed for the ranges of incidence angles (') and Reynolds numbers (Re) (0X B ' B 90X, 60 B Re B 160). The numerical model is adequately validated with the available experimental and numerical data from the literature. It is found that the presence of the upstream semi-circular cylinder at various incidence angles yields a rotational effect on the flow structures that evolve from the downstream circular cylinder. The modulation of the incidence angle reveals three separation regimes of the shed-vortex structures, which shows wake confluence. The dependencies of the coefficient of drag (CD) and the root mean square values of the lift coefficient (CL,rms) on the angles of incidence are examined for both of the cylinders. The frequency of vortex shedding increases with increasing ' and attains its peak value at phi similar to 30 degrees. The forced convective heat transfer for the semi-circular cylinder decreases with increasing ', whereas a contrasting trend is observed for the circular cylinder until phi similar to 45 degrees. The global stability analysis through the dynamic mode decomposition shows a stabilizing flow situation for the present range of operating parameters.

Automated summary

This study analyzes the transport characteristics and associated instability of a forced convective flow past a semi-circular cylinder at incidence with a downstream circular cylinder. Different incidence angles were found to impact the flow structures and reveal the wake confluence phenomenon.