Delayed Detached-Eddy Simulation and Particle Image Velocimetry Investigation of S-Duct Flow Distortion
Delayed Detached-Eddy Simulation and Particle Image Velocimetry Investigation of S-Duct Flow Distortion
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DOI：
10.2514/1.j055468
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发表时间：
2017-06-01
期刊：
影响因子：
2.5
通讯作者：
Chiereghin, Nicola
中科院分区：
文献类型：
--
作者：
Gil-Prieto, Daniel;MacManus, David G.;Chiereghin, Nicola
发动机进气道内的动态畸变会影响发动机的性能和工作性能。有必要更好地了解的主要流动机制，促进在S形进水口出口的流动畸变。本文采用延迟分离涡模拟方法，对S形通道流场的主要拟序结构进行了详细的分析。这种数值方法捕捉高度不稳定流场的特性的能力证明了对高分辨率，同步立体粒子图像测速测量在空气动力学界面平面。确定了管道出口处主要扰动的流场机制。在分离区周围交替产生频率为St = 0.53的顺时针和逆时针流向涡，促进了管道出口处的旋流切换。展向涡也以St = 1.06的频率从分离区脱落，并沿沿着分离中心线剪切层向下游对流。这导致了主要损失区域的垂直调制以及在空气动力学界面处的高速和低速流之间的速度梯度的波动。
The dynamic flow distortion generated within convoluted aeroengine intakes can affect the performance and operability of the engine. There is a need for a better understanding of the main flow mechanisms that promote flow distortion at the exit of S-shaped intakes. This paper presents a detailed analysis of the main coherent structures in an S-duct flowfield based on a delayed detached-eddy simulation. The capability of this numerical approach to capture the characteristics of the highly unsteady flowfield is demonstrated against high-resolution, synchronous stereoscopic particle image velocimetry measurements at the aerodynamic interface plane. The flowfield mechanisms responsible for the main perturbations at the duct outlet are identified. Clockwise and counterclockwise streamwise vortices are alternately generated around the separation region at a frequency of St = 0.53, which promote the swirl switching at the duct outlet. Spanwise vortices are also shed from the separation region at a frequency of St = 1.06 and convect downstream along the separated centerline shear layer. This results in a vertical modulation of the main loss region and a fluctuation of the velocity gradient between the high-and low-velocity flow at the aerodynamic interface plane.