레이놀즈 수에 따른 원형 실린더 주위의 3차원 음향장 및 유동특성에 관한 수치해석 연구

Abstract

It is important for understand of the flow around the vehicle, also it has been studied by many people. In particular, the flow around a circular cylinder has various flow character and it has difference flow characteristics by Reynolds number. In the past flow around the circular cylinder start the Karnman vortex, it generated between the critical Reynolds number(re=47) to 180, and show the 2-dimensional flow. The Karman Vortex change to 3-dimensional flow when the Reynolds numbers are bigger than 180 In this paper, study about flow & acoustic wave around circular cylinder with OHOC Scheme and a high order and high resolution numerical technique also used. The past flow around the circular cylinder has many kinds of flow characteristics, such as 2 kinds of 3d flow mode, B-mode, also reynolds number and spanwise length characteristics by Strouhal number, lift and drag coefficient are calculated and flow characteristics comparison with numerical study and experiment. After that fitness 2nd vortex in B-mode unstable regime verify the spanwise length. This paper research the basic aero-acoustic around the 3-d circular cylinder by flow field and past flow effect aero-acoustic filed's change.