機翼是航空飛行器升力的主要來源。失速是一種物理現象，由於飛行過程中較大的AOA（攻角）超過了臨界值，升力突然下降。 主要原因是機翼上方邊界層流的早期分離，導致分離流中產生渦流，這是大部分上翼表面的原因。 動態失速也是由於AOA週期性變化而導致機翼突然升力下降的情況。

由於這是一個流固耦合問題，因此本研究旨在使用直接施力型沉浸邊界（DFIB）方法建立內部數值模型來模擬動態失速。直接施力型沉浸邊界DFIB法的主要原理是在動量方程中添加虛擬力，以計算固體在流體上的合力。不需要使網格變形即可適合複雜的實體邊界。射線投射算法用於以DFIB方法識別機翼的幾何形狀。因為此問題處於一個紊流的條件下，該模型採用大渦模擬（LES）進行湍流計算。在平行計算方面，混合MPI/OpenMP用作已建立DFIB方法的平行計算算法，以提高計算效率。另一個值得探討的問題是在動態失速情況下控制翼型上的氣流。電漿控制用於防止動態失速。除此之外，提出並解釋了在DBD電漿制動器、拍打翼型以及湍流的影響下邊界層流的變化以及中渦旋對的演化。

An airfoil is the main source of lift in aeronautical vehicles. Stall is a physical phenomenon in which lift suddenly drops due to a large AOA (angle of attack) exceeding the critical value during flight. The main reason is the early separation of the boundary layer flow above the airfoil, resulting in vortices in the separated flow, which account for most of the upper airfoil surface. Dynamic stall is also a situation that the airfoil experiences a sudden lift drop as the AOA changes periodically.

Since it is a fluid-structure interaction problem, this study aims to use the Direct-Forcing Immersed Boundary (DFIB) method to establish the in-house numerical model for simulations of dynamic stall. The main principle of DFIB methods is to add a virtual force in the momentum equation for calculations of the resultant force of solid on fluid. It does not need to distort a grid to fit a complex solid boundary. A ray casting algorithm is used to identify the geometry of the airfoil in the DFIB method. Large eddy simulation (LES) is adopted for calculation of turbulence in the proposed model. The hybrid MPI/OpenMP structure is used as the parallel computing algorithm to improve the computing efficiency. Another worth-exploring point is control of airflow over the airfoil under dynamic stall. Plasma control is used to prevent dynamic stall. Additionally, the changes of boundary layer and the evolution of vortices flow under the influence of DBD actuator, turbulent flow and flapping airfoil are presented and explained in this study.

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