Journal ArticleDOI
Hot-Flow Simulation of Aeroacoustics and Suppression by Water Injection During Rocket Liftoff
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TLDR
In this article, a 1∶100 scaled-down model experimental setup that exactly replicates a launch vehicle and launch pad for simulating the vehicle liftoff is tested for its aeroacoustic environment.Abstract:
A 1∶100 scaled-down model experimental setup that exactly replicates a launch vehicle and launch pad for simulating the vehicle liftoff is tested for its aeroacoustic environment. The rocket exhaust consists of twin supersonic hot-air jets of Mach number 3.38. The role of shock noise is investigated in separate single-nozzle freejet and impinging-jet experiments with varying levels of overexpansion. The launch jet noise is suppressed by water jet injection into the exhaust plume for selected locations on the launch pad. Sound reduction up to 9 dB is achieved, and noise suppression continues to be effective up to 8De of vehicle altitude (De being the nozzle-exit diameter). The sound spectra continuously varies from that of impinging jets at the deflector duct and launch table to that of freejets, as the vehicle is lifting off. The noise sources in heated jets respond similar to those in the cold jet, but comparatively higher sound reduction levels are obtained for hot jets in the impinging flow phase of li...read more
Citations
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Journal ArticleDOI
Investigation on subsonic to supersonic flow around a sphere at low Reynolds number of between 50 and 300 by direct numerical simulation
TL;DR: In this paper, an analysis of flow properties around a sphere and its aerodynamic coefficients in the high-Mach-andlow-Reynolds-numbers conditions is carried out by direct numerical simulations solving the three-dimensional compressible Navier-Stokes equations.
Journal ArticleDOI
A review of impinging jets during rocket launching
TL;DR: In this article, the authors present an overview on progress and perspectives of the jet impingement research for rocket launching and discuss the interaction of impinging jets with multiphase flows.
Journal ArticleDOI
Direct numerical simulation of flow around a heated/cooled isolated sphere up to a Reynolds number of 300 under subsonic to supersonic conditions
TL;DR: In this article, an analysis of the flow properties around an isolated sphere under isothermal conditions for flows with high Mach numbers and low Reynolds numbers is conducted via direct numerical simulation (DNS) of the three-dimensional compressible Navier-Stokes equations.
Journal ArticleDOI
Numerical simulations of water spray on flame deflector during the four-engine rocket launching
TL;DR: In this article, the cooling effect with two types of water spray nozzle on the flame deflector during the four-engine launch vehicle take-off was studied, and the results showed that the high temperature regions, along the axis of engines on the deflector plate, have no significant temperature decreasing effect by water spray from the nozzles mounted on the apex of the fire deflector.
Journal ArticleDOI
Eulerian–Lagrangian direct numerical simulation of preferential accumulation of inertial particles in a compressible turbulent boundary layer
TL;DR: In this article, a direct numerical simulation of the dispersion and motion of inertial particles in a spatially developing compressible turbulent boundary layer at a Mach number of 2 is performed with the Eulerian-Lagrangian point particle method.
References
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Journal ArticleDOI
The sources of jet noise: experimental evidence
TL;DR: In this article, four different approaches are used to determine experimentally the sources of jet mixing noise: spectral and directional information measured by a single microphone in the far field, fine-scale turbulence, large turbulence structures of the jet flow, and a mirror microphone is used to measure the noise source distribution along the lengths of high speed jets.
Proceedings ArticleDOI
On the Two Components of Turbulent Mixing Noise from Supersonic Jets
TL;DR: In this paper, two similarity spectra, one for the noise from the large turbulence structures/instability waves of the jet flow, the other for the fine-scale turbulence, are identified.
Journal ArticleDOI
Shock associated noise of supersonic jets from convergent-divergent nozzles
Christopher K. W. Tam,H.K. Tanna +1 more
TL;DR: In this article, the authors derived a scaling formula that the intensity of shock associated noise varies as (Mj2 − Md2)2 where Mj and Md are the fully expanded jet operating Mach number and nozzle design Mach number, respectively.
Journal ArticleDOI
Aeroacoustics of hot jets
TL;DR: In this article, the effect of jet temperature on the noise radiated by subsonic jets was quantified and it was concluded that the change in spectral shape at high jet temperatures, normally attributed to the contribution from dipoles, is due to Reynolds number effects and not dipoles.
Journal ArticleDOI
Flow field and noise characteristics of a supersonic impinging jet
TL;DR: In this paper, the authors examined the flow and acoustic characteristics of an axisymmetric supersonic jet issuing from a Mach 1.5 converging-diverging (C-D) nozzle and impinging on a ground plane.