針對前傾噴流在橫風環境中，在不同的傾斜角及噴流對應橫風動量通量比時，在開放式的風洞中透過實驗方法研究流場與擴散特性。使用雷射輔助煙霧流場可視化的技術觀察短時間與長時間曝光流場;利用高速數據擷取系統將熱線風速儀在噴流剪流層上的瞬時速度數位化，並藉由快速傅利葉轉換技術計算剪流層渦漩結構的頻率特性、時間尺度與長度尺寸;應用二位元邊緣偵測技術於長時間曝光的流場照片，量測噴流擴散寬度與穿透高度;使用追縱氣體濃度檢測方法偵測噴流橫向擴散分佈及噴流軌跡;藉由質點影像速度儀量化不同流場特徵之橫風噴流。噴流迎風側剪流層的渦流結構呈現四個特徵流動模式：高衝擊橫風主導模態、高衝擊噴流主導模態、低衝擊橫風主導模態及低衝擊噴流主導模態。在橫流主導模態中，增加傾斜角消除迎風側剪流層的渦漩，而在噴流主導模態中，增加傾斜角則強化傾風側剪流層渦漩。在所有模態下，固定噴流對應橫風動量通量比，當傾斜角增加時，使得近管口區的噴流穿透高度增加，遠離噴流管口處的噴流穿透高度及擴散寬度皆增加。在接近管口區，高衝擊橫風主導模態的擴散寬度比低衝擊橫風主導模態大。在噴流主導模態，較高的傾斜角導致較大的噴流擴散寬度。橫風噴流在低衝擊噴流主導模態形成最佳的噴流擴散。

The flow and dispersion characteristics of a forward-inclined stack-issued jet in crossflow at various inclination angles (θ) and jet-to-crossflow momentum flux ratios (R) were experimentally studied in an open-loop wind tunnel. Short- and long-exposure flow patterns were examined using the laser-assisted smoke flow visualization technique. The instantaneous velocities of the upwind-side shear-layer were digitized by a hot-wire anemometer using a high-speed data acquisition system. The instability frequencies in the upwind-side shear-layer vortices were obtained by the fast Fourier transform method. The time scales and length scales of the upwind-side coherent flow structures and turbulent eddies were investigated. The binary edge-detection technique was applied to the long-exposure flow images to obtain the jet spread width and penetration height. Transverse distributions of jet dispersion and jet trajectories of jet in crossflow were determined using the tracer-gas concentration detection method. Time-averaged velocity fields of the forward-inclined stack-issued jet in crossflow at various characteristic flow modes were quantified by using PIV method. The upwind-side shear-layer vortices revealed four characteristic flow modes: high impingement-crossflow dominated mode, high impingement-jet flow dominated mode, low impingement-crossflow dominated mode, and low impingement-jet flow dominated mode. Increasing θ in the crossflow dominated regime eliminates the upwind-side shear-layer vortices, while increasing θ in the jet flow dominated regime emphasizes the upwind-side shear-layer vortices. As θ increases at a fixed R, the jet penetration height in both near- and far-field increases for all flow modes. Increasing θ at a fixed R increases jet spread width in the far field for all flow modes. In the near field, the jet spread width in the high impingement-crossflow dominated regime is larger than that in the low impingement-crossflow dominated regime. In the jet flow dominated regimes, higher θ values leads to greater jet spread width. The forward-inclined stack-issued jet in crossflow in low impingement-jet flow dominated regime reveals the best dispersion of the jet fluids.

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