Numerical investigation of acoustic refraction

Baum, Joseph D.; Levine, J.

doi:10.2514/3.9828

Cited by 11 publications

(22 citation statements)

References 20 publications

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“…This is the case most frequently encountered in an operating solid propellant rocket motor, which typically has an axial Mach number of 0(0.1) and a pressure oscillation of 1-2% of the mean value. Numerical studies by Baum and Levine (1987) are also concerned with this regime. We adopt Pridmore-Brown's solution form for traveling acoustic waves, iJ = F(K, y)e'("-), and seek plane-wave mode solutions.…”

Section: Technical Discussionmentioning

confidence: 99%

“…This phenomenon has received considerable attention in recent years due to its relevance to gasdynamic processes in rocket engines. Baum and Levine (1987) argue that the refraction-induced acoustic pressure enhancement or reduction on the solid propellant surface tends to alter its combustion characteristics. They conducted extensive numerical investigations of acoustic refraction phenomena based on Reynolds-averaged Navier-Stokes equations for compressible turbulent flow.…”

Section: Technical Discussionmentioning

confidence: 99%

“…One important conclusion from our analysis is that nonlinear effects are always negligibly small during the low Mach number mean flow-acoustic interactions. The discrepancy between the classical linear acoustic theory and the numerical and experimental studies indicated by Baum and Levine (1987) may be caused by differences in flow conditions, especially the sensitive physical parameters such as the mean flow Mach number, the wave amplitude and the wave frequency.…”

Section: 'R2+uy]f;mentioning

confidence: 99%

“…Our analysis shows that in a quasi-static oscillatory acoustic system, the alcoustic boundary layer is of constant thickness and a self-similar horizontal velocity profile exists across the layer. The variation of boundary layer structure and the formation of new boundary layers observed by Baum and Levine (1987) are possibly only transient phenomena, of importance on the very short time scale for which their initial-boundary value problems are solved. This research effort is directed at understanding the energy exchange mechanisms between the mean and the acoustic flow fields in a solid propellant combustion chamber.…”

Section: 'R2+uy]f;mentioning

confidence: 99%

See 3 more Smart Citations

AFOSR/ONR Contractors' Meeting on Combustion Rocket Propulsion Diagnostics of Reacting Flow Held in Ann Arbor, Michigan on 19-23 June 1989

Tishkoff¹,

Birkan²,

Roy³

et al. 1989

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Section: Technical Discussionmentioning

confidence: 99%

Section: Technical Discussionmentioning

confidence: 99%

Section: 'R2+uy]f;mentioning

confidence: 99%

Section: 'R2+uy]f;mentioning

confidence: 99%

See 2 more Smart Citations

AFOSR/ONR Contractors' Meeting on Combustion Rocket Propulsion Diagnostics of Reacting Flow Held in Ann Arbor, Michigan on 19-23 June 1989

Tishkoff¹,

Birkan²,

Roy³

et al. 1989

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“…In the model problem discussed in Ref. 4, an initially steady shear flowfield in a rigid walled axisymmetric cylinder is disturbed continuously at an inlet or outlet plane to generate unidirectional traveling acoustic waves. The waves move only a few acoustic wavelengths before computations are terminated, so that the quasisteady solution in Refs.…”

Section: Introductionmentioning

confidence: 99%

Standing acoustic waves in a low Mach number shear flow

Wang

Kassoy

1992

AIAA Journal

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Acoustic shear flow interactions are studied in a rectangular cavity bounded by impermeable duct walls parallel to the flow direction and special perpendicular acoustic reflectors that permit the passage of a fully developed, low Mach number shear flow. Fourier-series-based asymptotic solutions are constructed to provide an explicit description of the evolution of an initially imposed axial standing wave disturbance. The bulk convective motion of the shear flow is shown to be responsible for periodic axial waveform deformations. Additionally, transverse and oblique standing acoustic waves as well as single-frequency bulk oscillations arise from the refraction of the imposed axial acoustic disturbance by the mean flow velocity gradient. Combinations of these disturbances give rise to irregular acoustic pressure signals in the duct. Certain refraction induced transverse and oblique acoustic modes are amplified under resonant conditions. It is shown that, in the parameter ranges of solid rocket engines, the refraction and bulk convection effects are small, in general.

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Acoustically generated vorticity in an internal flow

et al. 2000

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A mathematical model is formulated to describe the initiation and evolution of intense unsteady vorticity in a low Mach number (M), weakly viscous internal flow sustained by mass addition through the sidewall of a long, narrow cylinder. An O(M) axial acoustic velocity disturbance, generated by a prescribed harmonic transient endwall velocity, interacts with the basically inviscid rotational steady injected flow to generate time-dependent vorticity at the sidewall. The steady radial velocity component convects the vorticity into the flow. The axial velocity associated with the vorticity field varies across the cylinder radius and in particular has an instantaneous oscillatory spatial distribution with a characteristic wavelength O(M) smaller than the radius. Weak viscous effects cause the vorticity to diffuse on the small radial length scale as it is convected from the wall toward the axis. The magnitude of the transient vorticity field is larger by O(M−1) than that in the steady flow.An initial-boundary-value formulation is employed to find nonlinear unsteady solutions when a pressure node exists at the downstream exit of the cylinder. The complete velocity consists of a superposition of the steady flow, an acoustic (irrotational) field and the rotational component, all of the same magnitude.

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Numerical investigation of acoustic refraction

Cited by 11 publications

References 20 publications

AFOSR/ONR Contractors' Meeting on Combustion Rocket Propulsion Diagnostics of Reacting Flow Held in Ann Arbor, Michigan on 19-23 June 1989

AFOSR/ONR Contractors' Meeting on Combustion Rocket Propulsion Diagnostics of Reacting Flow Held in Ann Arbor, Michigan on 19-23 June 1989

Standing acoustic waves in a low Mach number shear flow

Acoustically generated vorticity in an internal flow

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