Abstract The flow and mixing characteristics of a forward-inclined stack-issued jet at various inclination angles (θ) and jet-to-crossflow momentum flux ratios (R) were experimentally studied in an open-loop wind tunnel. Flow behaviors 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. Long-exposure flow images were processed using the binary edge-detection technique to obtain the jet spread width. Transverse dispersion of jet fluids was determined using tracer gas concentration detection. The upwind-side shear-layer vortices revealed four characteristic flow modes: the High impingement-crossflow dominated mode (about θ 15° and low R), and the Low impingement-jet flow dominated mode (about θ > 25° and high R). Increasing θ in the crossflow dominated regimes eliminated the upwind-side shear-layer vortices, while increasing θ in the jet flow dominated regimes emphasized the upwind-side shear-layer vortices. Increasing θ at a fixed value of R increased jet spread width in the far field in all modes. In the near field, at x/d

中文翻译：

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横流中前倾叠放射流的流动和混合特性

摘要 在开环风洞中，通过实验研究了在不同倾角 (θ) 和射流与横流动量通量比 (R) 下前倾叠放射流的流动和混合特性。使用激光辅助烟雾流动可视化技术检查流动行为。逆风侧剪切层的瞬时速度通过使用高速数据采集系统的热线风速计进行数字化。逆风侧剪切层涡的不稳定频率是通过快速傅里叶变换方法获得的。使用二元边缘检测技术处理长时间曝光的流动图像以获得射流传播宽度。射流流体的横向分散使用示踪气体浓度检测来确定。逆风侧剪切层涡流揭示了四种特征流动模式：高冲击横流主导模式（约 θ 15° 和低 R），和低冲击射流主导模式（约 θ > 25° 和高 R）。在横流主导区域增加 θ 消除了逆风侧剪切层涡，而在喷射流主导区域增加 θ 强调了逆风侧剪切层涡。在固定的 R 值下增加 θ 会增加远场中所有模式的射流扩散宽度。在近场中，在 x/d 在固定的 R 值下增加 θ 会增加所有模式下远场中的射流扩散宽度。在近场中，在 x/d 在固定的 R 值下增加 θ 会增加远场中所有模式的射流扩散宽度。在近场中，在 x/d