本文的目的為使用數值方法，以吹氣與吸氣壁邊界條件處理方式模擬幾何不規則外形以探討圓錐彈體在高攻角下，鼻端微小幾何不規則對非對稱渦流結構和彈體側向力(Side Force)的影響。數值方法採用人工壓縮法(Artificial Compressibility)、Osher-Chakravarthy MUSCL形式高解析度總變量縮減法(Total Variation Diminishing Scheme)，時間積分則採用隱式時間準確ALU(Approximate Lower/Upper Factorization)步進法。數值結果顯示，背風渦流結構的不對稱性會隨鼻端微干擾的圓周角位置、以及微干擾的強度達到某一門檻(Shreshold)大小以後而改變，讓原本較為遠離物體表面的弱渦流變為較接近物體表面，而原本較為接近物體表面的強渦流則變得較遠離物體表面，這個不對稱渦流結構性的變化導致物體側向力出現方向上的改變。另外，亦以吹氣與吸氣的組合模擬實驗微泡，並有著與實驗結果一致的趨勢，顯示出當微干擾的圓周位置在弱渦流側並與迎風停帶線的夾角為60°~90°的時候能有效減低側向力。

The objective of this work is to study the asymmetric vortices structure and the induced side force on a cone-cylinder body at high incidence. Both control-free and micro-balloon actuated flows were simulated. In the control-free case the effect of small geometric irregularity on the apex was studied first to see the sensitivity of the natural vortical flow development over a cone-cylinder body. Flow control enforced with micro-balloon actuation was then investigated. A previously developed incompressible flow solver which employs the artificial compressibility and the Osher-Chakravarthy upwind MUSCL type total variation diminishing scheme was used. Time-accuracy is achieved by implicit ALU(Approximate Lower/Upper factorization) time-marching augmented by Newton sub-iterations. Geometric alteration was modeled using blowing/suction boundary conditions. Results show that the asymmetry of the natural vortical structure changes with the circumferential position of the imposed disturbance on the apex. Moreover, at sensitive forcing locations, the strength of the disturbances may cause sudden structural change of the separated vortical flow when the volume flux, which simulates the disturbance on the apex, exceeds certain threshold value. The original weak separated vortices situated remotely from the body surface migrate closer to the body surface, while the original strong vortices get pushed far away from the body. The flip of the influential vortical structure results in the side force reversal of the cone-cylinder body. For the controlled flow study, blowing and suction strength was adjusted to yield similar micro-balloon height generated in the experiment. It was observed that, in the same effective forcing region, the enforcement of balloon control over the weak vortex side causes the basic pattern change of the vortex structure. A newly generated organized vortex structure in the vicinity of the original weak vortex side takes the role of the influential vortex, making the side force change significantly in the reversed trend.

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