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題 名 | 黏滯性對移動底床造波現象之影響 |
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作 者 | 張志華; 唐啟釗; | 書刊名 | 力學 |
卷 期 | 11:1 1995.03[民84.03] |
頁 次 | 頁25-35 |
分類號 | 440.137 |
關鍵詞 | 黏滯性; 移動潛體; 有限解析法; 貼壁座標; 流函數; Viscous damping; Submerged body; Finite-analytic method; Body-fitted grid; Stream function; |
語 文 | 中文(Chinese) |
中文摘要 | 二維淺水渠道中浸沒物體以近臨界速度U=gH(g為重力加速度,H為靜止水深)定 速移動, 將於物體前端產生孤立子列( soliton train )往其上游傳遞,並同時在下游產 生一低陷水域,緊接著振盪波列的自由液面變化現象。本文主旨在利用不同數值方法,以相 較於 gB ( generalized Boussinesq )或 fkdv ( forced kdv )方程式更一般化之方程 式探討上述相關現象,並著重於探討黏滯性對自由液面及內部流場瞬變特性之影響。根據二 維不可壓縮流體假設,在瞬時貼壁座標( transient boundary-fitted coordinate )系統 上考慮完全非線性自由表面邊界條件,應用有限解析法( finite analytic method )以數 值疊代法求解流場流函數、 渦度函數及自由表面位置之時間精確解( time-accurate solution )。 數值計算之結果顯示黏滯之影響的確在物體附近產生相當程度之影響,並對 尾跡流動、渦度於近底床傳遞情形均造成複雜流動現象。 |
英文摘要 | As a submerged disturbance moving along a shallow water channel with a transcritical velocity U=gH, where g is gravitational acceleration, H the undisturbed water depth, the free surface emerges a series of solitary waves together with an oscillatory wave train following the depleted surface region. Theme of this paper is to investigate the viscous counterparts based on the stream function-vorticity formulations together with complete free-surface boundary conditions. However, we consider the more general equations than that of traditional gB (generalized Boussinesq) or fkdv (forced kdv) ones. The finite analytic (FA) method is applied to discretize governing equations. Furthermore, the transient body-fitted grid system is utilized to conform the irregular moving boundaries. The numerical results show, behind the disturbance, the trains of oscillatory waves are not only strongly damped but propagated much slowly as a result of viscous dissipation in the wake region following the disturbing body. |
本系統中英文摘要資訊取自各篇刊載內容。