ABSTRACT

We present an experimental and numerical study of the flow downstream of honeycomb flow straighteners for a range of Reynolds numbers, covering both laminar and turbulent flow inside the honeycomb cells. We carried out experiments with planar particle image velocimetry (PIV) in a wind tunnel and performed numerical simulations to perform an in-depth investigation of the three-dimensional flow field. The individual channel profiles downstream of the honeycomb gradually develop into one uniform velocity profile. This development corresponds with an increase in the velocity fluctuations which reach a maximum and then start to decay. The position and magnitude of the turbulence intensity peak depend on the Reynolds number. By means of the turbulence kinetic energy (TKE) budget it is shown that the production of TKE is dominated by the shear layers corresponding to the honeycomb walls. The near-field and far-field decay of the turbulence intensity can be described by power laws where we used the position where the production term of the TKE reaches its maximum as the virtual origin.

摘要

我们对一系列雷诺数的蜂窝流矫直器下游的流动进行了实验和数值研究，涵盖了蜂窝单元内的层流和湍流。我们在风洞中进行了平面粒子图像测速 (PIV) 实验，并进行了数值模拟，以对三维流场进行深入研究。蜂窝下游的各个通道剖面逐渐发展成一个均匀的速度剖面。这种发展对应于速度波动的增加，达到最大值然后开始衰减。湍流强度峰值的位置和大小取决于雷诺数。通过湍流动能 (TKE) 预算，表明 TKE 的产生由对应于蜂窝壁的剪切层控制。湍流强度的近场和远场衰减可以用幂律描述，我们以TKE的产生项达到最大值的位置作为虚拟原点。