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. For each case, two wind-tunnel flow configurations were considered; one with and the other without adding small spires. In both configurations, the results show low levels of linear coherence between the incident velocity and surface pressure except at the very low frequencies. The nonlinear coherence is also very low. Consequently, the relation between frequency components of incident velocity and pressure fluctuations is not direct. The results suggest that, because of the required averaging, frequency-domain analysis is not the most suitable technique to determine the relation between incident velocity and fluctuating pressures.