Experimental Study and Simulation of Rocket Engine Freejet Noise

Varnier, Jean

doi:10.2514/2.1199

Cited by 68 publications

(18 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The noise components mentioned previously have been studied extensively for cold jets with fully expanded Mach numbers M j 2 and in a few works [1,3,[7][8][9][10] for hot jets with M j ' 3. Their contributions to heated, rocketlike jet noise, however, have not been well established, even if Mach waves radiated by linear instability waves [4,19] are usually assumed to be dominant [3,4].…”

mentioning

confidence: 99%

“…Introduction P ROPULSIVE jets generated by booster rockets of space launchers are characterized by high stagnation pressure and temperature, resulting [1] in fully expanded exit Mach numbers M j usually around 3, and acoustic Mach numbers M a > M j . Such jets are known to radiate strong acoustic fields, which are assumed to be dominated by Mach waves [2][3][4][5][6].…”

mentioning

confidence: 99%

“…Nomenclature a n = relative contribution of azimuthal modes n c = local sound speed c 1 = ambient field sound speed f = frequency f c = cutoff frequency f shock = central frequency of the broadband shockassociated noise f up = frequency of the upstream-propagating shockassociated noise L VS = first shock length from vortex sheet, 2M = Strouhal number of the upstream-propagating shock-associated noise T e = exit temperature u axis = centerline mean axial velocity u c = convection velocity u e = exit velocity u j = equivalent fully expanded exit velocity hu z i = mean axial velocity hu 02 z i = mean-square axial velocity fluctuations hu 02 z i n = mean-square axial velocity fluctuations due to mode n jû 2 z jSt e ; n = two-dimensional power spectral densities z 1 = 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 I. Introduction P ROPULSIVE jets generated by booster rockets of space launchers are characterized by high stagnation pressure and temperature, resulting [1] in fully expanded exit Mach numbers M j usually around 3, and acoustic Mach numbers M a > M j .…”

mentioning

confidence: 99%

“…Such jets are known to radiate strong acoustic fields, which are assumed to be dominated by Mach waves [2][3][4][5][6]. Few aerodynamic and acoustic data are unfortunately available [1,[7][8][9][10], and noise sources are still to be fully described [11].…”

mentioning

confidence: 99%

See 3 more Smart Citations

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

2011

View full text Add to dashboard Cite

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

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

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

2011

View full text Add to dashboard Cite

show abstract

“…Recently, Varnier [7] carried out a series of static tests on rocket engines and suggested several improvements to the NASA method. Many improvements to the theoretical models of jet noise have been recently proposed in the literature (for example, the work of Tam [8], Tam et al [9], Tanna [10,11], and others).…”

Section: Introductionmentioning

confidence: 99%

Suppression of High Mach Number Rocket Jet Noise by Water Injection

Sankaran¹,

Ignatius²,

Ramkumar³

et al. 2009

Journal of Spacecraft and Rockets

View full text Add to dashboard Cite

The present work experimentally investigates suppression of the sound level from an underexpanded jet of Mach number 2.8 by water injection. The jet is produced by a solid rocket motor being static test fired. Water is injected from a radial distance of 5.2 jet diameters, at different axial locations from the exit of the nozzle, at two different angles of injection relative to the downstream jet axis. The ratio of mass flow rates of water to the nozzle exhaust gas (referred to as the mass flow rate ratio) and the injection pressure are varied independently. Acoustic measurements are performed at a radius of 30 jet diameters, over angles in the range of 30-130 deg, relative to the downstream jet axis. Sound levels continuously decrease by 10 dB with the increase in the angle of observation. With water injection, higher levels of reduction in sound are observed in the upstream quadrant. Injection closer to the nozzle exit leads to better reduction, mainly due to suppression in the high-frequency range when observed from downstream, but it is almost in the entire frequency range as observed at the upstream locations. At intermediate mass flow rate ratios, an optimum injection pressure exists for maximum noise suppression, due to the penetration of water to the potential core and its evaporation there at high injection pressures. The results affirm that the validity of many past studies obtained on water injection to suppress noise levels on simulated jets can be extended to an actual rocket situation.

show abstract

Toward accurate simulation and analysis of strong acoustic wave phenomena—A review from the experience of our study on rocket problems

Fujii

Nonomura

Tsutsumi

2010

Numerical Methods in Fluids

View full text Add to dashboard Cite

SUMMARYThis paper gives an overview of the numerical simulations for the analysis of strong nonlinear acoustic waves during rocket development, with the emphasis on recent ones carried out using large-scale supercomputers. After the discussion on the difficulties encountered in such simulations, a computational study of blast wave propagation conducted for estimating the safety distance of a rocket is presented. The study was conducted about 20 years ago and the result showed the advantages of the moving grid method as well as the importance of grid resolution studies. A recent study on rocket plume acoustics is then presented. The result shows that the generation and propagation of Mach waves from the plume shear layers are key features to be captured. Direct simulations of such flows have now become feasible owing to the developments in computers and numerical schemes. Then, problems that still remain unsolved are discussed. Our study so far has been limited to simulations using structured grids of high spatial resolution although direct simulations of strongly nonlinear acoustic waves are becoming feasible. More studies have to be carried out for developing highly accurate schemes for unstructured grid systems for the applications to flow configurations over complex geometries. With such improvements, computational fluid dynamics (CFD) would become a still better effective tool for the analysis and estimation of nonlinear acoustic phenomena, especially in aerospace applications.

show abstract

Experimental Study and Simulation of Rocket Engine Freejet Noise

Cited by 68 publications

References 10 publications

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

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

Suppression of High Mach Number Rocket Jet Noise by Water Injection

Toward accurate simulation and analysis of strong acoustic wave phenomena—A review from the experience of our study on rocket problems

Contact Info

Product

Resources

About