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 the controller can
actuate upon the desired turbulent structures. A comprehensive database from
direct numerical simulations of turbulent channel flow is used for this
purpose, spanning a Reynolds-number range ReΟββΌ550β5200. A spectral
analysis reveals that the streamwise velocity is most strongly coupled to the
linear term of the wall-pressure, at a wall-scaling of Ξ»xβ/yβ14
(and Ξ»xβ/yβ8.5 for the wall-normal velocity). When extending
the analysis to both homogeneous directions in x and y, the peak-coherence
is centred at Ξ»xβ/Ξ»zββ2 and Ξ»xβ/Ξ»zββ1 for pwβ and u, and pwβ and v, respectively. A stronger coherence is
retrieved when the quadratic term of the wall-pressure is concerned, but there
is only weak evidence for a wall-attached-eddy type of scaling. Experimental
data are explored in the second part of this work: wall-pressure data are
denoised and subsequently used for predicting the binary-state of the
streamwise velocity fluctuations in the logarithmic region. A binary estimation
accuracy of up to 72% can be achieved by including both the linear and
quadratic terms of the wall-pressure. This study demonstrates that a controller
for wall-bounded turbulence (solely relying on wall-pressure data) has merit in
terms of a sufficient state estimation capability, even in the presence of
significant facility noise