The effects of jet pulsation intensity and excitation Strouhal number on the flow and dispersion characteristics of dual parallel plane jets at a low Reynolds number of 200 were experimentally studied so that the transition from laminar to turbulence was focused. A hot-wire anemometer was used to record the jet velocities. The flow patterns were obtained using the laser-light sheet assisted smoke flow visualization technique. Jet spread widths were derived from the long-exposure images using the binary edge detection method. The jet fluid dispersion characteristics were examined using the tracer-gas concentration detection technique. Four characteristic flow modes (discrete coherent vortices, contiguous coherent vortices, early vortex breakup, and lateral dispersion) were identified in the domain of the jet pulsation intensity and excitation Strouhal number. At small jet pulsation intensities, discrete and contiguous coherent vortices appeared at low and high excitation Strouhal numbers, respectively. The vortices appearing in the jet shear layers broke up slowly and caused small jet expansions and turbulent intensities, thus inducing a low efficiency of jet fluid dispersion. The early vortex breakup mode was induced by the low-frequency back-and-forth flow motions in the near region at large jet pulsation intensities and low excitation Strouhal numbers. Large turbulence fluctuations caused by the early vortex breakup increased the jet dispersion significantly. At large jet pulsation intensities and excitation Strouhal numbers, high-frequency back-and-forth flow motions in the region near the jet exits significantly reduced the time-averaged axial momentum and induced large lateral jet expansion and jet fluid dispersions.

通过实验研究了低雷诺数200时射流的脉动强度和激发Strouhal数对双平行平面射流的流动和弥散特性的影响，从而重点研究了从层流到湍流的过渡。使用热线风速仪记录射流速度。使用激光片辅助烟流可视化技术获得了流型。使用二进制边缘检测方法从长时间曝光的图像中得出喷射扩散的宽度。使用示踪气体浓度检测技术检查喷射流体的分散特性。四种特征流模式（离散相干涡，连续相干涡，早期涡旋破裂，和横向弥散）在射流脉动强度和激发Strouhal数域中确定。在小的射流脉动强度下，低和高激发斯特劳哈尔数分别出现离散和连续的相干涡。出现在射流剪切层中的涡流缓慢破裂，并引起小的射流膨胀和湍流强度，因此导致射流流体分散的效率低下。早期涡旋破裂模式是由在大射流脉动强度和低激发Strouhal数下在附近区域的低频来回流动运动引起的。由早期涡旋破裂引起的大的湍流波动显着增加了射流的分散。在大射流脉动强度和激发斯特劳哈尔数下，