Two-point radiation statistics from large-scale turbulent structures within supersonic jets

Cheng, Jianhui; Goldschmidt, James; Shen, Weiqi; Ukeiley, Lawrence; Miller, Steven A.

doi:10.1177/1475472x211005413

Cited by 3 publications

(1 citation statement)

References 58 publications

(94 reference statements)

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“…These observations demonstrate that the primary noise generation mechanisms existing in the full LES are captured by the MFP. Furthermore, the existence of sideline radiation signatures in the perturbation field suggests that MFP can used to model the contribution of large-scale structures to the sideline noise which may have feedback control benefits with wing mounted sensors [60].…”

Section: Comparison Of Near-field Wavepackets With Lesmentioning

confidence: 99%

A Time-Domain Linear Method for Jet Noise Prediction and Control Trend Analysis

Prasad,

Gaitonde

2021

Preprint

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Large-scale turbulent structures in the form of coherent wavepackets play a significant role in the generation of prominent shallow-angle noise radiation of jets. Economical prediction tools often model these wavepackets in the frequency-domain using stability modes of the mean flow. The use of simplifying choices, such as parabolized equations and azimuthal decomposition, provide efficient methods but can impose constraints on rate of streamwise variation of the mean state or geometric complexity. The current investigation develops a time-domain linearized Navier-Stokes-based approach predicated on the mean basic state for two goals: (i) to obtain the radiated shallow-angle noise field, including that from imperfectly expanded jets containing shock trains, and (ii) to estimate noise control trends with actuator frequency. A previously developed implicit linearization technique repurposing native non-linear Navier-Stokes code capabilities avoids any additional constraints on nozzle geometry, while its time-domain nature facilitates control analysis through transient pulse response. Two other integral components of the method are the sifting of linearized perturbations to isolate the acoustic component according to Doak's momentum potential theory (MPT), and subsequently Dynamic Mode Decomposition (DMD) to analyze the response in different spectral ranges. Comparisons with well-validated Large Eddy Simulation (LES) databases in different spectral ranges show accurate model predictions for super-radiative shallow angle noise, including for hot jets from military-style nozzles. For control frequency effectiveness, the transient perturbation growth characteristics are processed to delineate the distinct effects of the excitation on vorticity versus the MPT acoustic variable. For a specific jet with extensive published experimental data using plasma actuators, it is shown that the method correctly predicts noise amplification at lower frequencies and reduction at higher values, at the observed crossover location.Considerations on the costs associated with the approach, which exploits linearity to extract results at multiple frequencies with each simulation, are outlined.

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Section: Comparison Of Near-field Wavepackets With Lesmentioning

confidence: 99%

A Time-Domain Linear Method for Jet Noise Prediction and Control Trend Analysis

Prasad,

Gaitonde

2021

Preprint

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A time-domain linear method for jet noise prediction and control trend analysis

Prasad

Gaitonde

2022

Aerospace Science and Technology

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Effect of heat source on kinetic energy transfer in compressible homogeneous shear turbulence

et al. 2022

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The effects of heat sources on kinetic energy transfer in compressible homogeneous shear turbulence are studied using numerical simulations at turbulent Mach numbers 0.1 and 0.4 for two levels of heat source. It is found that the strong heat source can significantly enhance both positive and negative components of subgrid-scale (SGS) kinetic energy flux and pressure–dilatation. After adding a strong heat source, compression motions enhance the positive SGS flux, and expansion motions enhance the negative SGS flux at a low turbulent Mach number. According to the Helmholtz decomposition, we found that the solenoidal and dilatational components of pressure–dilatation and SGS kinetic energy flux are increased greatly by a strong heat source at a low turbulent Mach number. The solenoidal mode plays a dominant role in the kinetic energy transfer process, but the contribution of the dilatational mode is not negligible. The dilatational component of the production term is increased by a strong heat source at a low turbulent Mach number, providing the main source of kinetic energy to the dilatational mode. The strong heat source also enhances the kinetic energy exchange between solenoidal mode and dilatational mode through nonlinear advection at a low turbulent Mach number. Moreover, the strong heat source enhances pressure anisotropy, redistribution of the kinetic energy of two transverse components, and energy transfer from internal energy to the kinetic energy through pressure–dilatation term. At a high turbulent Mach number, the strong heat source has little impact on the solenoidal and dilatational components of kinetic energy transfer terms.

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Two-point radiation statistics from large-scale turbulent structures within supersonic jets

Cited by 3 publications

References 58 publications

A Time-Domain Linear Method for Jet Noise Prediction and Control Trend Analysis

A Time-Domain Linear Method for Jet Noise Prediction and Control Trend Analysis

A time-domain linear method for jet noise prediction and control trend analysis

Effect of heat source on kinetic energy transfer in compressible homogeneous shear turbulence

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