A numerical investigation is made into the use of linear predictive (Wiener
) filters to predict flow quantities in the near-wall region of a turbulent
boundary layer for use in active control algorithms. Optimal filters for t
he prediction of Reynolds stress and fluctuating streamwise velocity compon
ents using wall-shear stress information are developed and their dependence
on the number and location of shear sensors is explored. It is found that
a densely populated, wall-based, sensor system can predict the near-wall Re
ynolds stress with good accuracy, and that 76% of the optimal performance c
an be achieved with as few as four sensors whose locations coincide with th
e strongest weights of the Wiener filter derived using a very dense network
of input sensors. (C) 2000 American Institute of Physics. [S1070- 6631(00)
50112-3].