I am interested in studying the recirculation region in a backward facing step at high Reynolds number. Presently, I am getting the value of Strouhal number as 0.012. In order to ensure that my simulation results are correct, I needed some papers that have studied the same, however, I found most of the research to be concentrated on the vortical shedding rather than the recirculation region. Can anyone provide me with some insights on the values that I am getting?
The Strouhal number for recirculation region is much lesser than that of the vortical shedding, but I wanted a quantitative justification for the same.
I am not sure to understand your problem... at high Re number the BFS flow is turbulent and highly 3D. There is no unique recirculation region after the step, what are you analysing?
The paper attached below mentions the Strouhal Number for recirculation region to be in the range 0.068-0.078 at a Reynolds Number of 9000. My problem is a bit similar with the only difference in the Reynolds Number(20000). I am getting a Strouhal Number of 0.012 for my case, so I wanted to ensure that my simulation results are correct by validating it with available literature
You could study the time evolution of the reattachment length as we defined here
https://www.researchgate.net/profile/Filippo_Maria_Denaro/publication/229725014/inline/jsViewer/5a525030aca2725638c5faef
Thank you for sharing the work. I was able to see the variation of reattachment length with time. As mentioned in the earlier paper that I've shared, the frequency of oscillation of the reattachment length lies within the frequency of the recirculation region, hence this could provide an idea regarding the frequency of oscillation of the recirculation region. However, I am interested in particularly higher Reynolds Number~20000 where the Recirculation Region has a much lower frequency which subsequently vanishes as the Reynolds number is increased further
Again, how do you define the “recirculation region”? It is not a unique region, as you can see, in the spanwise direction there is a locus of reattachement lengths.
I can observe a region of recirculation beginning at the corner of the step and ending at the reattachment point, which is the region of my interest
But that is for a 2d sketch, in you case you have to repeat the search of a reattachment lenght along the spanwise direction for several positions. Thus, for each station you should evaluate a St number and then make an ensemble averaging.
Thanks a lot Ahmed Abdelhameed . This is exactly what I was looking for. I'll now proceed towards the validation and provide an update regarding the same
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