Print Email Facebook Twitter Reynolds-number scaling of wall-pressure–velocity correlations in wall-bounded turbulence Title Reynolds-number scaling of wall-pressure–velocity correlations in wall-bounded turbulence Author Baars, W.J. (TU Delft Aerodynamics) Dacome, G. (TU Delft Aerodynamics) Lee, Myoungkyu (University of South Alabama) Date 2024 Abstract Wall-pressure fluctuations are a practically robust input for real-time control systems aimed at modifying wall-bounded turbulence. The scaling behaviour of the wall-pressure-velocity coupling requires investigation to properly design a controller with such input data so that it can actuate upon the desired turbulent structures. A comprehensive database from direct numerical simulations (DNS) of turbulent channel flow is used for this purpose, spanning a Reynolds-number range. Spectral analysis reveals that the streamwise velocity is most strongly coupled to the linear term of the wall pressure, at a Reynolds-number invariant distance-from-the-wall scaling of (and for the wall-normal velocity). When extending the analysis to both homogeneous directions in and, the peak coherence is centred at and for and, and and, respectively. A stronger coherence is retrieved when the quadratic term of the wall pressure is concerned, but there is only little evidence for a wall-attached-eddy type of scaling. An experimental dataset comprising simultaneous measurements of wall pressure and velocity complements the DNS-based findings at one value of k, with ample evidence that the DNS-inferred correlations can be replicated with experimental pressure data subject to significant levels of (acoustic) facility noise. It is furthermore shown that velocity-state estimations can be achieved with good accuracy by including both the linear and quadratic terms of the wall pressure. An accuracy of up to 72 % in the binary state of the streamwise velocity fluctuations in the logarithmic region is achieved; this corresponds to a correlation coefficient of 0.6. This thus demonstrates that wall-pressure sensing for velocity-state estimation - e.g. for use in real-time control of wall-bounded turbulence - has merit in terms of its realization at a range of Reynolds numbers. To reference this document use: http://resolver.tudelft.nl/uuid:ad0c4af8-58e7-4aea-a77f-b06166cf0fc4 DOI https://doi.org/10.1017/jfm.2024.46 ISSN 0022-1120 Source Journal of Fluid Mechanics, 981 Part of collection Institutional Repository Document type journal article Rights © 2024 W.J. Baars, G. Dacome, Myoungkyu Lee Files PDF reynolds-number-scaling-o ... ulence.pdf 5.01 MB Close viewer /islandora/object/uuid:ad0c4af8-58e7-4aea-a77f-b06166cf0fc4/datastream/OBJ/view