49th Fluid Dynamics Conference /the 35th Aerospace Numerical Simulation Symposium (June 28-30, 2017. National Olympics Memorial Youth Center), Shibuya-ku, Tokyo, Japan
抄録（英）
Because of the singularity of the center axis, there is difficulty to accurately simulate a flow close to the axis. Vortex breakdown is known as a typical phenomenon, which takes place near the axis, and then, it is significantly important to resolve the flow around the axis. In this paper, a fully three-dimensional incompressible flow was simulated in a cylindrical coordinate system by a staggered mesh without artificial viscosity. In such a configuration, solving a radial momentum equation on the axis is required but it has singularity on the axis. Here, the singularity was removed by L’Hospital’s rule and the radial momentum equation was solved on the axis. In order to prevent the radial velocity component on the axis from a multi-value function, single-valued-reconstruction was applied. Under these considerations, a swirling flow in a closed cylinder with a rotating bottom was numerically simulated and the flow structure of a vortex breakdown, which was a bubble type, was examined. Although our result showed non-zero velocity in the radial direction on the axis, it reduced to a machine zero as the continuity equation converges. At last, it was shown that the topology of a bubble-type vortex breakdown lead to that of an axisymmetric spherical vortex (a spheromak).
内容記述
形態: カラー図版あり
内容記述（英）
Physical characteristics: Original contains color illustrations
円筒容器内渦崩壊現象のフル三次元シミュレーション
AA1730011014.pdf
(874.2KB)
