Chamfer effect in the step and Eddy corner of the backward-facing step fluidic oscillator

Abstract

Abstract A backward-facing step fluidic oscillator (BFSFO) was modified by creating chamfers at step and Eddy corners with variations from 20% to 80%. Analysis was conducted using CFD methods involving an SST k-ω turbulence model. Reynolds numbers ranged from 3 × 10⁴ to 5.5 × 10⁴. Results concluded that a 20% step corner chamfer model is highly optimal for active flow control devices, capable of producing significan frequency ( f ) (an average increase of 5.44%), reducing average pressure drop (ΔP ave ), and maintaining an optimal pressure fluctuation (PF). Conversely, a 20% Eddy corner chamfer configuration shows an excellent ability to reduce ΔP ave , while maintaining a notably high PF. This is achieved by shrinking recirculation bubble size within mixing chambers. Therefore, this specific Eddy corner chamfer BFSFO model is highly recommended for use in combustion or heat transfer applications. Frequency increases across baseline, step, and Eddy corner chamfer models occur due to higher velocity return flows inside feedback channels, which helps accelerate jet movement cycles.