航空宇宙技術
Online ISSN : 1884-0477
早期公開論文
早期公開論文の2件中1~2を表示しています
  • 松島 紀佐, 小林 大志, 清水 亮介
    論文ID: JSASS-D-17-00041
    発行日: 2017年
    [早期公開] 公開日: 2017/11/08
    ジャーナル 認証あり 早期公開

    For the aerodynamic design of aircraft, CFD has made a remarkable progress to provide lift, drag and surface pressure distribution collaborating with wing tunnel experiment. However, not much information is known about the flow phenomena in wakes of airplanes and wings. In the article, we concentrate on wake flow analysis as a post work of computations and experiments done for APC-I workshops. Through the analysis, we have found that wing tip vortices and boundary layers of a wing affect velocity distribution on a wake, while only the tip vortices do pressure. The precise prediction of wake physics deeply depends on grid resolution quality in subspaces such as cross-sectional planes in a wake away from an airplane surface, for both of experiment and computation.

  • 澤木 悠太, 河合 宗司, 澤田 惠介
    論文ID: JSASS-D-17-00034
    発行日: 2017年
    [早期公開] 公開日: 2017/10/17
    ジャーナル 認証あり 早期公開

    The conventional spectral volume (SV) method for three-dimensional tetrahedral unstructured mesh is extended to use hexahedral mesh. In the test calculations of linear scalar advection problem and diffusion problem, the formal spatial order of accuracy is achieved even for skewed computational meshes. The Spalart Allmaras turbulence model implemented in the present code is verified by calculating the grid-converged skin friction of turbulent boundary layer on a flat plate. Then verified code is applied to compute the flowfield around the NASA-CRM. In this study, we examine the agreement of the computed aerodynamic coefficients with the corresponding experimental data for different angles of attack. We also examine the change of aerodynamic coefficients with varying Reynolds number, although the experimental data is not available. It is shown that the present SV code can predict aerodynamic coefficients around the cruise angle of attack conditions fairly well. When higher Reynolds number is assumed, the computed lift increases while the viscous drag is reduced, as is expected. On the other hand, the pressure drag is increased with increasing Reynolds number due to the shock wave on the wing which moves toward downstream.

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