F221 準定常現象における解析手法について(F-22 大迎角物体まわりの非定常・剥離流(3),一般講演)

概要

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When Re is in a range of 30〜10^4, drag coefficient C_D can be 4/Re0.5. When Re>10^3, fluid pressure on the cylinder accounts for 87% of C_D. Roshko also showed the pressure distribution around a circular cylinder. Achenbach showed the experiment data of C_D near the critical Re of cylinders with different course surfaces Therefore, most of the researches are based on measuring the steady state fluid, but very less on the approaches of how to measure or calculate the transient fluid or quasi-steady state flow. In this paper, the difficulties of getting an accurate quasi-steady state flow result in laminar range are examined in detail with the well-known example of a cylinder under different flow rates in the fluid field. The variation of the pressure and shear force against the flow rate, other parameters and different numerical methods have shown that it is not easy to explain the steady state calculation result of a quasi-transient flow, especially, when inertial relaxations are used to stabilize the analysis.
日本流体力学会の論文
2004-08-09