Prediction of the nonlinear response of an acoustically forced flow with linearized Navier-Stokes equations

摘要

The prediction of self-sustained aeroacoustic oscillations has been the topic of numerous of theoretical studies, but obtaining quantitative predictions on practical configurations is still challenging. In this study we use particle image velocimetry to record flow data at an acoustically excited T-Junction subject to low-Mach grazing flow. Data is recorded for several acoustic excitation amplitudes and frequencies. This allows to formulate a model predicting the non-linear response of the system with Navier-Stokes equations linearized around different mean flows measured with different excitation amplitudes and frequencies. This linearized perturbation approach gives a good prediction of the spatial repartition of the velocity fluctuations and predicts their amplitude to a reasonable degree. The test rig serves as a surrogate for the aeroacoustic behavior of deep closed cavities.