A numerical performance model for piezoelectrical actuators for jet noise reduction

The use of small-scale disturbances to control turbulence production and sound generation in regions of high shear has long been a topic of interest. We have previously reported the use of piezoelectrically driven, tab-type actuators to drive disturbances in the initial shear layer of a cold jet to accomplish this task. Particle imaging velocimetry along with phased array and far field microphones were used to interrogate the flow and acoustic fields, respectively. The complexities of turbulent flows, along with the strong interaction between the actuators and the fluid, make optimization of the actuator system difficult. We are therefore developing a numerical actuator performance model to gain insight into the actuator-flow physics. Los Alamos National Laboratory's (LANL) CFDLib provides the framework of our fluid-structure model. CFDLib is a library of stable and mature algorithms that can be assembled to address a wide-variety of problems. We utilize the generalized 3-D URANS multifluid algorithms with a two-fluid model that allows us to describe the motion of both gas and actuators on the same computational grid. The paper describes the modeling approach and presents initial comparisons with recent particle imaging velocimetry measurements.