Computing Jet Screech: A Complex Aeroacoustic Feedback System

Jet Screech Noise Computation

“…These equations are discretized and solved using the a− weighted-average CE/SE scheme with α = 1 and = 0.5, see [13,14,22] for further details.…”

“…This inflow plane is recessed by two cells so as not to numerically restrict or influence the feed-back loop. The numerical scheme [13,14] Initially, the entire flow field is at rest and at ambient conditions, i.e., (using nondimensional variables)…”

“…It is a challenge in that the numerical scheme must: (i) handle shock waves, (ii) resolve acoustic waves with low dispersion and dissipation errors, (iii) resolve the instability waves in the jet shear layer and their interaction with the core shock-cell structure, and (iv) have an effective non-reflecting boundary condition. Successful direct computation of screech for circular jets have been carried out by Shen and Tam [10,12] using the Dispersion Relation Preserving, or DRP, scheme and by the present authors [13][14][15][16] using a NavierStokes solver based on the space-time conservation element and solution element, or CE/SE, method [17,18]. In their 3-D computation, Shen and Tam [12] adopted a spectral method in the azimuthal direction and by using only a limited number of spectral functions achieved substantial savings of computer memory and CPU time, without deterioration of accuracy.…”

A 3-D CE/SE Navier-Stokes Solver with Unstructured Hexahedral Grid for Computation of Nearfield Jet Screech Noise

“…The present authors [12][13][14] successfully computed axisymmetric near-field screech noise for round jets using the recent CE/SE (space-time conservation-element and solution-element) method utilizing (unstructured) triangulated grids. Because of the implementation (based on flux balance) of the non-reflecting boundary conditions (NRBC), a much smaller near field computational domain can be used with this method.…”

Near-Field Noise Computation for a Supersonic Circular Jet

“…In the present paper, encouraged by the successful computation of 2-D axisymmetric and 3-D screech noise for round jets [22][23][24][25], a second-order (in space and time) finite-volume scheme of low dissipation is adopted for LES computation of a supersonic jet of Mach number 1.4. The scheme is the 3-D CE/SE Navier-Stokes solver using a hexahedral grid.…”