Improved Time-Dependent Flowfield Solution for Solid Rocket Motors

Majdalani, Joseph; Moorhem, W. K. Van

doi:10.2514/2.7507

Cited by 98 publications

(30 citation statements)

References 12 publications

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“…(i) the original flow-turning loss, confirmed by Flandro (1995) in his analysis and subsequently by Majdorani and Van Moorhem (1998) and Malhotra (2001) should be included in computations of linear stability; (ii) an additional contribution overlooked in the onedimensional analysis and first identified by Flandro (1995) must be included: that is the part as discussed above, proportional to the local gradient of acoustic pressure parallel to the boundary; and according to the limited results of numerical simulations the vorticity waves seem to be rapidly destroyed following their generation, by viscous dissipation and interactions with turbulence in the flow; if that result holds, then it may be appropriate to ignore interactions of the vorticity waves with the acoustic field within the volume, and with the flow in the exhaust nozzle.…”

Section: ~~~~~mentioning

confidence: 60%

“…~n other words, energy is transferred from the acoustlc field to the oscillating vorticity connected with the mean flow. Both analysis (Flandro, 1995, Majdorani, 1998 and numerical simulation (Roh et al 1995) suggest that the vorticity waves are dissipated rapidly through the action of viscous stresses and interaction with turbulence.…”

Section: ~~~~~mentioning

confidence: 99%

“…The analysis by Flandro 1995, Malhotra and Flandro 1997and Majdorani and Van Moorhem 1998 have shown that, in addition to the basic flow turning loss found originally in the one-dimensional analysis, there are two other contributions: 1) the gradient of oscillatory pressure parallel to the surface causes, by conservation of mass, a velocity fluctuation normal to the lateral boundary, thereby causing additional loss associated with momentum exchange between the incoming and bulk flows; and 2) within the chamber there are volumetric interactions between the vorticity waves and the acoustic waves, causing a gain of energy for the acoustic field.…”

Section: ~~~~~mentioning

confidence: 99%

See 2 more Smart Citations

Combustion instabilities - Mating dance of chemical, combustion, and combustor dynamics

Culick

2000

36th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit

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Section: ~~~~~mentioning

confidence: 60%

Section: ~~~~~mentioning

confidence: 99%

Section: ~~~~~mentioning

confidence: 99%

See 1 more Smart Citation

Combustion instabilities - Mating dance of chemical, combustion, and combustor dynamics

Culick

2000

36th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit

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“…With extensive work already in place for the treatment of radial boundary layers forming over an injecting a͒ sidewall, [24][25][26][27][28] the present article also seeks to investigate the structure of the unsteady axial boundary layers forming over an injecting headwall in the presence of transverse waves. The motivation to tackle the axial boundary layer analog is inspired by experimental observations suggesting that the highest pressure amplitudes and therefore most severe waves often occur near the injector face.…”

Section: Introductionmentioning

confidence: 99%

Acoustic streaming in simplified liquid rocket engines with transverse mode oscillations

2010

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This study considers a simplified model of a liquid rocket engine in which uniform injection is imposed at the faceplate. The corresponding cylindrical chamber has a small length-to-diameter ratio with respect to solid and hybrid rockets. Given their low chamber aspect ratios, liquid thrust engines are known to experience severe tangential and radial oscillation modes more often than longitudinal ones. In order to model this behavior, tangential and radial waves are superimposed onto a basic mean-flow model that consists of a steady, uniform axial velocity throughout the chamber. Using perturbation tools, both potential and viscous flow equations are then linearized in the pressure wave amplitude and solved to the second order. The effects of the headwall Mach number are leveraged as well. While the potential flow analysis does not predict any acoustic streaming effects, the viscous solution carried out to the second order gives rise to steady secondary flow patterns near the headwall. These axisymmetric, steady contributions to the tangential and radial traveling waves are induced by the convective flow motion through interactions with inertial and viscous forces. We find that suppressing either the convective terms or viscosity at the headwall leads to spurious solutions that are free from streaming. In our problem, streaming is initiated at the headwall, within the boundary layer, and then extends throughout the chamber. We find that nonlinear streaming effects of tangential and radial waves act to alter the outer solution inside a cylinder with headwall injection. As a result of streaming, the radial wave velocities are intensified in one-half of the domain and reduced in the opposite half at any instant of time. Similarly, the tangential waves are either enhanced or weakened in two opposing sectors that are at 90°angle to the radial velocity counterparts. The second-order viscous solution that we obtain clearly displays both an oscillating and a steady flow component. The steady part can be an important contributor to wave steepening, a mechanism that is often observed during the onset of acoustic instability.

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“…For important recent exceptions, see work by Flandro, 20 Majdalani and Van Moorhem, 21 and Roh et al…”

Section: Effects Of Noise and Nonlinear Combustionmentioning

confidence: 99%

Influence of Random Excitations on Acoustic Instabilities in Combustion Chambers

Burnley

Culick

2000

AIAA Journal

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Although ows in combustors contain considerable noise, arising from several kinds of sources, there is a sound basis for treating organized oscillations as distinct motions. That has been an essential assumption incorporated in virtually all treatments of combustion instabilities. However, certain characteristics of the organized or deterministic motions seem to have the nature of stochastic processes. For example, the amplitudes in limit cycles always exhibit a random character, and even the occurrence of instabilities seems occasionally to possess some statistical features. Analysis of nonlinear coherent motions in the presence of stochastic sources is, therefore, an important part of the theory. We report a few results for organized oscillations in the presence of noise. The most signi cant de ciency is that, because of the low level of current understanding, the stochastic sources of noise are modeled in ad hoc fashion and are not founded on a solid physical basis appropriate to combustion chambers.

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Improved Time-Dependent Flowfield Solution for Solid Rocket Motors

Cited by 98 publications

References 12 publications

Combustion instabilities - Mating dance of chemical, combustion, and combustor dynamics

Combustion instabilities - Mating dance of chemical, combustion, and combustor dynamics

Acoustic streaming in simplified liquid rocket engines with transverse mode oscillations

Influence of Random Excitations on Acoustic Instabilities in Combustion Chambers

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