On the transition to turbulence of a viscoplastic fluid past a confined cylinder: A numerical study

• We present 3D simulations of transitional viscoplastic flow past a confined cylinder.
• Modes A and B 3D instabilities are shown for the first time in the viscoplastic wake.
• A linear relation of the RecrRecr for the inset of 3D instabilities with Bingham number is shown.
• A modified Reynolds number allows a collapse of the Strouhal–Reynolds number plot.
• Significant structural differences between the Newtonian and Bingham wakes are noted.

Three-dimensional direct numerical simulations of a Bingham fluid flowing past a confined circular cylinder have been used in order to investigate viscoplastic effects in the wake-transition regime. The case of a cylinder confined in a plane channel with a fixed blockage ratio (ratio of the cylinder diameter to the channel height) of 0.20.2 has been studied, for values of the Bingham number and Reynolds numbers (based on the cylinder diameter and bulk flow velocity) in the range 0