An experimental study of jet noise part II: Shock associated noise

Tanna, H. K.

doi:10.1016/0022-460x(77)90494-1

Cited by 192 publications

(80 citation statements)

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“…The BBSAN for the two higher Mach numbers seems to be roughly omnidirectional. This property has already been noted in the literature (see, e.g., Tanna [10] and Viswanathan et al [17]). An undulation in the levels is visible however, which is similar for both values of M j and can also be observed in the measurements of Viswanathan et al for a cold jet at M j 1.36 (see their Fig.…”

Section: Effect Of Screech On the Amplitude Of The Broadband Shocksupporting

confidence: 72%

“…Harper-Bourne and Fisher [9] adapted Powell's model involving an array of stationary sources to derive some observed properties of this noise component. Tanna [10] performed extensive acoustic measurements to evaluate this semi-analytical model. Much progress on the BBSAN was made around 1980 at NASA by Norum and Seiner [11], who associated advanced aerodynamical measurements, such as static pressure [12] or turbulence fluctuation levels [13], to near-field and far-field acoustic measurements.…”

Section: Introductionmentioning

confidence: 99%

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Broadband Shock-Associated Noise in Screeching and Non-Screeching Underexpanded Supersonic Jets

2013

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The effect of screech tones on the broadband shock-associated noise of underexpanded jets is investigated experimentally. Screech is removed by means of a notched nozzle, and the properties of the broadband shockassociated noise in the screech-free configuration are compared to that in a screeching flow. It is first demonstrated that the suppressing technique used is nonintrusive in that it does not alter the shock-cell structure of the jet plume. It is then shown that screech has an effect on the aerodynamics of the jet, which induces changes in the broadband shockassociated noise. Indeed, screech accelerates the damping of the shock-cell pattern, leading to an attenuation of the broadband shock-associated noise and a shifting of this noise component to higher frequencies. Moreover, a tuning between the peak frequency of the broadband shock-associated noise and the screech frequency is observed. It is also deduced from the directivity of the broadband shock-associated noise in the far field that the convective velocity in the shear layer is modified in the presence of screech tones.

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Section: Effect Of Screech On the Amplitude Of The Broadband Shocksupporting

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Broadband Shock-Associated Noise in Screeching and Non-Screeching Underexpanded Supersonic Jets

2013

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“…Other sound sources appear when a shock-cell structure is present in the jet plume generated by the adjustment of static pressure to the ambient field at the nozzle exit. The interactions between turbulent structures and shock cells result in broadband noise [19,20] propagating both in the upstream and downstream directions [19,21]. If the jet shear layer at the nozzle exit is sufficiently receptive to the upstream-propagating acoustic waves [22][23][24], a feedback loop can also be established.…”

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confidence: 99%

Investigation of a High-Mach-Number Overexpanded Jet Using Large-Eddy Simulation

2011

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An initially laminar overexpanded round jet at an exit Mach number of 3.30 and a Reynolds number of 10 5 is calculated by compressible large-eddy simulation. The near field obtained by large-eddy simulation is also propagated to the acoustic far field by solving the full Euler equations to take into account the nonlinear propagation effects. Both computations are performed using low-dissipation finite differences in combination with an adaptive shock-capturing method. The jet originates from a straight pipe nozzle of radius r e , including lips of thickness 0:05r e . At the pipe exit, Blasius mean flow profiles are imposed, and static pressure and temperature are equal to 0:5 10 5 Pa and 360 K, resulting in fully adapted and acoustic Mach numbers, respectively, of 2.83 and 3.47. The jet flowfields, as well as the acoustic near and far fields, are described in detail and compared with data of the literature. The turbulent mechanisms developing in the jet are investigated, using spectral and azimuthal decompositions of the velocity fluctuations along the shear layers. Same analyses are applied to the acoustic fields, in order to discuss the properties of jet noise components. In this way, Mach waves, shock-associated noise, screech tones, and turbulent mixing noise are identified. = first shock location on the jet axis = specific heat ratio r = mesh size in the radial direction z = mesh size in the axial direction = boundary-layer thickness in the pipe nozzle 0:5 = jet half-width e = exit molecular viscosity e = exit density = radiation angle measured according to the flow direction

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“…The interactions between turbulent structures and shock cells thus generate broadband noise 18,19 propagating both in the upstream and downstream directions. 18,20 If the jet shear layer at the nozzle exit is sufficiently receptive to the upstream propagating acoustic excitation, [21][22][23] a feedback loop can also occur, and generate a tonal noise called screech, first observed by Powell 24 in the 1950s. The screech tone radiates mainly in the upstream direction, and Tam & al., 22 for instance, have shown that the screech fundamental frequency and the central frequency of the broadband shock-associated noise collapse in the upstream direction.…”

Section: -10mentioning

confidence: 99%

Direct Noise Computation of a Shocked and Heated Jet at a Mach Number of 3.30

Cacqueray

Bogey

Bailly

2010

16th AIAA/CEAS Aeroacoustics Conference

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An overexpanded axisymmetric jet at an exit Mach number of 3.30 and a Reynolds number of 10 5 is computed by compressible large-eddy simulation (LES) to determine directly its radiated sound field, using low-dissipation schemes in combination with an adaptative shock-capturing method. At the jet nozzle exit, static pressure and temperature are respectively equal to 0.5 × 10 5 Pa and 360 K, and a laminar flow profile is imposed. To assess the validity of the simulation, the mean aerodynamic field and the near-field pressure levels, obtained directly by LES, are compared to available literature data. The axial velocity fluctuations in the shear-layer are also characterized using azimuthal decomposition, and exhibit properties close to those observed in screeching jets. The acoustic field is dominated by axisymmetric and first azimuthal modes, and noise sources are investigated from the acoustic near field: Mach waves, shock-associated noise and turbulent mixing noise occuring around the end of the potential core are identified.

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An experimental study of jet noise part II: Shock associated noise

Cited by 192 publications

References 1 publication

Broadband Shock-Associated Noise in Screeching and Non-Screeching Underexpanded Supersonic Jets

Broadband Shock-Associated Noise in Screeching and Non-Screeching Underexpanded Supersonic Jets

Investigation of a High-Mach-Number Overexpanded Jet Using Large-Eddy Simulation

Direct Noise Computation of a Shocked and Heated Jet at a Mach Number of 3.30

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