Flow Pattern Visualization of an Axisymmetric Stagnation Flow

軸對稱停滯區流場型態之探討

魏欽益(Chin-Yi Wei) ； 苗君易(Jiun-Jih Miau)

《中國航空太空學會學刊》 26卷4期 (1994/12) Pp. 311-318

https://doi.org/10.6124/TAASRC.199412_26(4).05

摘要

本文旨在探討軸對稱停滯流之流場特性，並比較其與二維停滯區渦流拉伸作用之差別。相對於二維停滯流沿着流線方向作用的渦流拉伸現象而言，軸對稱停滯流的渦流拉伸受到圓周徑向交互作用的影響，以至於三維停滯點的不穩定性遠大於二維停滯線，而軸對稱停滯區附近則由四種流場次結構取代了二維停滯區的反向渦流對結構。此外，軸對稱停滯流在停滯區對速度擾動的放大效果則不如二維停滯流顯著。

關鍵字

軸對稱停滯流 ； 渦流拉伸 ； 流場次結構

並列摘要

Experiments on flow near the stagnation region of an axisymmetñc bluff body show that the circumferential interaction effect of vortex stretching plays an important role on the development of flow substructures, the amplification of velocity fluctuation, and the enhancement of momentum and heat transfer in the axisymmetric stagnation region. The three-dimensional effect of the vortex stretching leads four types of flow substructures in the axisymmetric stagnation region. The stagnation point of the axisymmetric stagnation flow oscillates more violently than the stagnation line of the two-dimensional one. While the amplification of velocity fluctuation in the axisymmetric stagnation region is less significant than that in the two-dimensional one.

並列關鍵字

Axisymmetric stagnation flow ； Vortex stretching ； Flow substructure