Time-domain simulations of sound propagation in a flow duct with extended-reacting liners

A full discrete dispersion analysis of time-domain simulations of acoustic liners with flow

The effect of flow over an acoustic liner is generally described by the Myers impedance condition. The use of this impedance condition in time-domain numerical simulations has been plagued by stability issues, and various ad hoc techniques based on artificial damping or filtering have been used to stabilise the solution. The theoretical issue leading to the ill-posedness of this impedance condi...

Sound Propagation in Slowly Varying 2D Duct with Shear Flow

Sound propagation in uniformly lined straight ducts with uniform mean flow is well established by its analytically exact description in duct modes [1, 2, 3]. In cross-wise nonuniform flow there are still modes, although the (Pridmore-Brown) equation that describes them is in general not solvable in terms of standard functions [4, 5, 6, 7, 8, 9] and has to be solved numerically. These modal solu...

Prediction of a Turbulent Reacting Duct Flow with Significant Radiation

Numerical Methods for Reacting Gas Flow Simulations

In this study, various numerical schemes for transient simulations of 2D laminar reacting gas flows, as typically found in chemical vapor deposition reactors, are proposed and compared. These systems are generally modeled by means of many stiffly coupled elementary gas phase reactions between a large number of reactants and intermediate species. The purpose of this study is to develop robust an...

Closed-loop control of flow-induced sound in a flow duct with downstream resonant cavities.

A closed-loop-controlled surface perturbation technique was developed for controlling the flow-induced sound in a flow duct and acoustic resonance inside downstream cavities. The surface perturbation was created by piezo-ceramic THUNDER (THin layer composite UNimorph Driver and sEnsoR) actuators embedded underneath the surface of a test model with a semi-circular leading edge. A modified closed...