Reynolds Stress Deflections of the Bivane Anemometer

Abstract

We show that a bivane anemometer or other elevation angle sensing device records a nonzero mean angle when responding to cross-correlated fluctuations in a mean wind. Our analysis shows how this mean offset can be used to derive the wind-aligned Reynolds stress directly. This theory is applied to a historical data set. It is first shown that the prior derivation of a mean vertical wind component is erroneous, and then that reinterpretation of results in terms of the Reynolds stress response is consistent with other aspects of the record.