정방형 실린더의 모서리 원형화에 따른 유동의 이차 불안정성

초록

The present study performed numerical analysis for the flow instability in the flow past a square cylinder with rounded corners in laminar flow. The previous study found that the critical Reynolds number(Rec) of the primary instability is maximum at r/D=0.25(r is the corner radius and D is the cylinder diameter). This means that the flow with r/D=0.25 is more stable than the circular or square cylinders. Furthermore, this study performed floquet stability analysis to detect the onset of the secondary instability depending on the corner radius. To implement the cylinder cross-section, we adopted an immersed boundary method with marker particles. The main parameters are the corner radius and Reynolds number(Re). With r/D=0(square), 0.25, 0.5(circular) we calculated the critical Reynolds number and the dominant spanwise wavelength of the instability modes.