針對脈衝噴流水平流過一平板(稱為脈衝壁面噴流)，以實驗方法研究脈衝壁面噴流之流動行為與速度特性。實驗參數包含脈衝頻率與噴流雷諾數。當平板未被安裝時，使用熱線風速儀量測噴流出口瞬時速度的振盪特性，並且，亦量測壁面噴流的軸向與徑向的速度分佈及紊流強度分佈;利用流場可視化的技術，擷取脈衝壁面的流場衍化過程。在脈衝頻率與噴流雷諾數的域 上，可畫分出兩個特徵模態，在低脈衝頻率時，流場特徵是模態A。噴流沿著壁面上方流動，在噴流柱氣上形呈不規則的渦漩結構。在高脈衝頻率時，流場特徵為模態B。在噴流出口形成一領導環狀渦漩，往下游移動時渦漩結構變形、失去凝續性，最後在下游區域轉變為一泡芙狀渦漩結構。流場的特徵行為，主要授到脈衝頻率與噴流振盪情形所支配。當吸氣速度在噴流出口形成時，流場的特徵為模態B。模態A的紊流強度比模態B大。流場行為與速度特性的關係在本文中亦被研究與討論。

The flow behavior and velocity properties of a pulsed wall jet flowing tangentially over a flat plate were investigated experimentally. The experiments were performed with various excitation frequencies and jet Reynolds numbers. A hot-wire anemometer was utilized to detect the instantaneous velocities of the pulsed jet without installing flat plate, and the axial and radial distributions of the mean velocities and turbulent intensities of the pulsed wall jet. The flow evolution process of the pulsed wall jet was captured by flow visualization technique. Two characteristic flow modes were identified in the domain of excitation frequency and jet Reynolds number. The flow characteristics are dominated by the excitation frequency and jet pulsation condition. At low excitation frequency, the Mode A appeared. The jet flows across the flat plate and evolves vortical structures which are not orderly. At high excitation frequency, the Mode B appeared. A leading vortex ring evolved from jet exit moves downstream, deforms, loses the coherency, and then becomes a puff in the downstream region. As suction velocity is generated at jet exit, the flow characteristic exhibits Mode B. Turbulence intensities in Mode A are higher than those in Mode B. The relationship between flow behaviors and velocity properties were examined and discussed.

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