Abstract
The interaction between turbulent axisymmetric wakes plays an important role in many industrial applications, notably in the modeling of wind farms. While the nonequilibrium high-Reynolds-number scalings present in the wake of axisymmetric plates has been shown to modify the averaged streamwise scalings of individual wakes, little attention has been paid to their consequences in terms of wake interactions. We propose an experimental setup that tests the presence of nonequilibrium turbulence using the streamwise variation of velocity fluctuations between two bluff bodies facing a laminar flow. We have studied two different sets of plates (one with regular and another with irregular peripheries) with hot-wire anemometry in a wind tunnel. We show that the wake-interaction length, which quantifies the streamwise position where the wakes start interacting, can be deduced from the streamwise profiles of turbulence intensity, a quantity that is easy to resolve even in challenging field measurements. By acquiring streamwise profiles for different plate separations and identifying the wake-interaction length for each separation it is therefore possible to study the interaction between two axisymmetric turbulent wakes in terms of its energy cascade and in this case to show that the interaction between them is consistent with nonequilibrium scalings. This work also generalizes previous studies concerned with the interaction of plane wakes to include axisymmetric wakes. We find that a simple mathematical expression for the wake-interaction length based on nonequilibrium turbulence scalings can be used to collapse the streamwise developments of the second, third, and fourth moments of the streamwise fluctuating velocity.
8 More- Received 2 June 2022
- Accepted 4 November 2022
DOI:https://doi.org/10.1103/PhysRevFluids.7.114606
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