What is it about?
Flow over a bluff body creates a Von Karnman street. The intriguing aspect is the shedded vortices arrange themselves and led to the shear layer in the far downstream and result into another vortex street called secondary vortex street. In this study, we analyzed what is the physical mechanism led to this and how this frequency related to primitive variables like pressure, temperature and velocity
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Why is it important?
Flow over bluff body is canonical study which has varied applications in the flow over tall buildings, heat exchangers and many complicated flows can be modeled as canonical flows. For example, jets in cross flow can be modeled as a flow over a small vertical cylinders, movement of the micro organisms (spherical in shape) is similar to flow over a cylinder in 2D
Perspectives
It is very an interesting physics how a small vortex shedding can lead to major structural damage or enhance the heat transfer through mixing or increase form drag. There is a rich literature on how primary vortex shedding, Von Karman vortex street, can lead to it. The interesting aspect is along with primary vortex street, there is a secondary vortex street in the far downstream. Many of us are not aware of it or some ignore it as it far downstream but it could be significant if there is a system of the cylinders in the flow (eg., buildings in a row, heat exchanger tubes). I hope our article on the physical and spectral mechanism of secondary vortex street would shed light on it and benefit the community.
Venkatesh Pulletikurthi
Purdue University
Read the Original
This page is a summary of: On the development of low frequency structures in near and far laminar wakes, Physics of Fluids, February 2019, American Institute of Physics,
DOI: 10.1063/1.5081050.
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