ON FREQUENCY-DOMAIN ANALYSIS OF THE RELATION BETWEEN INCIDENT TURBULENCE AND FLUCTUATING PRESSURES

The linear and nonlinear correlations between frequency components of incident velocity and pressure fluctuations on surface mounted prisms are investigated. Normal and oblique incidence cases are considered. F or each case, two wind-tunnel flow configurations were considered; one with and the other without adding small spires. In both configuration s, the results show low levels of linear coherence between the inciden t velocity and surface pressure except at the very low frequencies. Th e nonlinear coherence is also very low. Consequently, the relation bet ween frequency components of incident velocity and pressure fluctuatio ns is not direct. The results suggest that, because of the required av eraging, frequency-domain analysis is not the most suitable technique to determine the relation between incident velocity and fluctuating pr essures.