著者

内田 孝紀 荒屋 亮 Uchida Takanori Araya Ryo

出版者

[九州大学応用力学研究所]

雑誌

九州大学応用力学研究所所報 (ISSN:13455664)

巻号頁・発行日

no.142, pp.55-62, 2012-03

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In order to simulate unsteady three-dimensional airflow around urban city area with characteristic length scales of the order of kilometers, we have been examining the large-eddy simulation (LES) technique using a finite-difference method (FDM). In this paper, using the LES technique, we have performed the calculation of buoyant gas diffusion around real urban area with huge computational grids. The various patterns of gas diffusion are clarified, and airflow is also locally accelerated or decelerated, due to the topographic and the obstacle effects.

著者

坂本 端樹 宮崎 俊昌 庄司 多津男 芦川 直子 徳永 和俊 増崎 貴 大宅 薫 相良 明男 佐藤 浩之助

出版者

九州大学応用力学研究所

雑誌

九州大学応用力学研究所所報 (ISSN:13455664)

巻号頁・発行日

no.134, pp.61-64, 2008-03

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We have also been developing a plasma-wall interaction (PWI) simulator of which plasma source is a steady-state RF helicon wave plasma supply to demonstrate in situ and real-time measurement and to study PWI phenomena. A helical antenna is surrounding a cylindrical quartz tube of which outer diameter is ~5 cm. The antenna is connected to an RF power supply of which power is up to 5kW through a matching box. A set of two coils produces an axial magnetic field of 0.05T at the plasma center. At present, the electron density at the plasma center is up to ~3 x 10^18 m^(-3) and electron temperature is up to ~10eV. Rather high plasma flux density of ~4 x 10^22 m^(-2) s^(-1) to the substrate has been obtained.

著者

山之口 勤 土井 浩一郎 澁谷 和雄 青木 茂

出版者

九州大学応用力学研究所

雑誌

九州大学応用力学研究所所報 (ISSN:13455664)

巻号頁・発行日

no.135, pp.95-99, 2008-09

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Recent studies point out the relationship between global environmental change and retreat of Antarctic ice sheet. Grounding line is a marginal zone where grounded continental ice sheet flow out to the ocean and just start to afloat and is one of the important parameters for the estimation of ice mass flux at Antarctica. However the precise position and detailed feature of grounding line haven't decided because its positions difficult to find from surface of ice sheet. Synthetic Aperture Radar (SAR) is a microwave imaging sensor and SAR sensor illuminate microwave to the ground, then observe its backscattered microwave from ground, interferometric SAR (InSAR) is an application technique of SAR data to measure the line-of-sight distance change using a pair of SAR data and most suitable technique for the detection of grounding line because InSAR can detect the tidal motion of ice shelf. Extracted grounding lines are geometrically corrected and projected onto Polar Stereographic Coordinate and compared with conventional dataset which name is ADD. Planimetric difference of grounding line between ADD and InSAR extracted one attains to 5000m at Riisar Larsen Peninsula, East Antarctica and 9500m at Burke Island, West Antarctica. In this study we confirmed the effectiveness of InSAR technique and revealed the incompleteness and inaccuracy of ADD data. Then, we plan to develop grounding line database at whole Antarctica. The icesheet-iceshelf boundary mainly laid at three regions on Antarctica, where East Antarctica(25°W-400°E), West Antarctica (85°W-165°W) and Antarctic Peninsula (50°W-60°W). We also introduce the development plan of this database.