分子気体力学 / Molecular gas dynamics
非常に小さい系における気体の流れや低圧気体の流れでは、分子同士の衝突頻度が稀になり、気体の状態は局所平衡状態から外れます。このような流れを個々の粒子の運動ではなく、粒子の集団的・統計的振舞いとして調べます。
希薄気体におけるマグナス効果 / Inverse Magnus effect in rarefied gas
流体中を運動する回転球には揚力（運動方向に垂直な力）が働く。気体分子運動論にもとづく研究で、気体中の球に働く揚力は球の大きさに影響を受け、球半径がある閾値を下回ると、揚力の向きが逆向きになることがわかった。
When moving in a fluid, a rotating sphere or cylinder experiences a transverse force. This effect is known as the Magnus effect. We showed that the transverse force acting on a sphere reverses its direction when the Knudsen number (i.e., the reciprocal ratio of the sphere radius to the molecular mean free path) exceeds a certain threshold.
- S. Taguchi and T. Tsuji, Inversion of the transverse force on a spinning sphere moving in a rarefied gas, DOI: https://doi.org/10.1017/jfm.2021.1048
熱尖端流による一方向流れ / One-way-flow driven by a thermal edge flow
一様に加熱したU字型物体を気体中に配置することで一方向の流れを取り出せることが数値計算でわかりました。
Uniformly heated U-shaped bodies placed in a gas can produce a net flow. We confirmed it numerically.
- S. Taguchi, T. Tsuji, One-way flow over uniformly heated U-shaped bodies driven by thermal edge effects, DOI: https://doi.org/10.1038/s41598-022-05534-y
不連続的な壁面温度によって生じる定常流 / A steady flow induced by a discontinuous surface temperature. There is no external force.
- S. Taguchi and T. Tsuji, On the motion of slightly rarefied gas induced by a discontinuous surface temperature, DOI: https://doi.org/10.1017/jfm.2020.332
- S. Taguchi and T. Tsuji, A generalized slip-flow theory for a slightly rarefied gas flow induced by discontinuous wall temperature, DOI: https://doi.org/10.1007/978-3-030-82946-9_14
瞬間的に自転を始める球によって生じる非定常流れ / Transient behavior of a gas induced by a sphere impulsively starts to rotate
Featured in Focus on Fluids
- S. Taguchi, T. Tsuji, and M. Kotera, Transient behavior of a rarefied gas around a sphere caused by impulsive rotation, DOI: https://doi.org/10.1017/jfm.2020.907
Satoshi Taguchi 