藤井 孝藏

Flow field and aerodynamic performance of the Mars airplane with a complete aircraft configuration are analyzed by RANS simulations. At the Reynolds number of 3.3x10⁴, a flow field is solved by an unstructured three-dimensional compressible CFD solver (LS-FLOW). Here, the Mars airplane is assumed to have the Ishii airfoil as the main wing shape. The Ishii airfoil is known as its good performance at the low Reynolds number condition. An objective of the present study is to clarify flow structures around a complete aircraft, for optimization of design of the Mars airplane. The results show that the features of the aerodynamic coefficients correspond to those of experimental results and the contribution of the main wing is significant on the aerodynamic characteristics of the entire airplane.

Aerodynamic characteristics and flow fields around an owl-like airfoil at a chord Reynolds number of 23,000 are investigated using two-dimensional laminar flow computations. Computed results demonstrate that the deeply concaved lower surface of the owl-like airfoil contributes to lift augmenting, and both a round leading edge and a flat upper surface lead to lift enhancement and drag reduction due to the suction peak and the presence of the thin laminar separation bubble near the leading edge. Subsequently, the owl-like airfoil has higher lift-to-drag ratio than the high lift-to-drag Ishii airfoil at low Reynolds number. However, when the minimum drag is presented, the Ishii airfoil gains lift coefficient of zero while lift coefficient of the owl-like airfoil does not becomes zero. Furthermore, a feature of unsteady flow structures around the owl-like airfoil at the maximum lift-to-drag ratio condition is highlighted.

自らが発行する学術論文誌をより有意義なものにすることは多くの学会にとって共通の課題である。3万人を超える学会員を有する日本機械学会では，2007年に英文誌の再編を行ったが，わずか7年で，和文誌，英文誌を含めた大規模な再編を行うに至った。再編にかかわる議論は多くの学会に共通な事項を多数含んでいる。本稿は，再編に至る背景，学会内での議論の経緯，再編の考え方，再編後の姿などを記すもので，その一部でも他学会の参考になることを期待している。