Journal

Adam Nickels, Lawrence Ukeiley, and Robert Reger

2018

A method for estimating the velocity fluctuations, hydrodynamic pressure fluctuations, and far-field acoustic pressure in a planar turbulent wall jet is examined. The Reynolds number based on nozzle height and exit velocity is 25,500. Streamwise-aligned, two-component particle image velocimetry and surface pressure measurements are obtained synchronously along the center line of the wall jet. Modified stochastic estimation is used to estimate a low-dimensional representation of the time-dependent velocity field, and performance metrics for the evaluation of the estimates are presented. The use of proper orthogonal decomposition in the estimation is evaluated against the estimation of individual velocity vectors from the measurements to investigate the filtering effect of using a subset of proper orthogonal decomposition modes in the velocity reconstruction. The velocity estimates are used to solve Poisson’s equation for the time-dependent hydrodynamic pressure fluctuations. Curle’s acoustic analogy is evaluated using the estimated velocity and pressure and compared with far-field acoustic measurements via a phased array of microphones. The estimated acoustic spectrum scaled by spanwise integration width is comparable to scaled measurements of the acoustic spectrum. The estimation method highlights the importance of the interaction between the pressure and velocity fields to the acoustic generation process. Read More: https://arc.aiaa.org/doi/abs/10.2514/1.J057042

AIAA Journal

56

11

10/15/2018

https://arc.aiaa.org/doi/abs/10.2514/1.J057042

https://doi.org/10.2514/1.J057042