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• W1674788118 abstract "Noise is an important factor in certifying an airplane and more restrictive noise regulations have demanded the design of quieter aircraft, with much of the emphasis focused on lower jet-noise emission. Previous passive and active noise-reduction strategies required parametric experiments or cut-and-try approaches, a fact largely attributed to the complexity of turbulence as a source of sound and to the subtlety of the sound-production mechanism. Both aeroacoustic theory and high-fidelity simulation have demonstrated that turbulence-generated noise can be predicted with sufficient accuracy; however, they have not been able to generally guide noise-reduction efforts so far.Adjoint-based optimization provides a unique and useful tool to pursue jet-noise reduction in a systematic approach. The adjoint of the perturbed and linearized Navier – Stokes equations is crafted to provide the control sensitivity in a direction of decreasing noise. Thus, despite the complexity of jet turbulence in the physical space, noise-reducing controls can be directly explored in a control parameter space. Prior work has shown that adjoint-based controls are capable of significantly suppressing the noise from two-dimensional subsonic free shear flows via a subtle modification of large-scale vortex dynamics.The adjoint-based optimization is used here to reduce the sound radiation of a pressure-matched Mach 1.3 cold jet computed using high-fidelity, non-dissipative, high-order finite differences on generalized curvilinear meshes. A large-eddy approximation is conducted with the smallest scales of turbulent motion approximated using the dynamic Smagorinsky sub-grid-scale model. For the time horizon over which the control is applied, the most intense noise events are almost completely removed. At a jet exhaust angle of 30 degree, the far-field peak spectral noise reduction is 5.6 dB at the jet column mode frequency and the overall sound pressure level is reduced by 1.6 dB. At the 90 degree (sideline) angle, the noise reduction is insignificant; however, there is no adverse noise increase as has commonly been found in experimental noise-reduction efforts.Fourier spectral analysis and the proper orthogonal decomposition are used to investigate the jet turbulence before and after the noise-reducing control is applied. The large-scale coherent vortical motion is slightly, but importantly, adjusted to reduce the noise. Most notably, vortex coalescence is demonstrated to be associated with the intermittent sound-generating mechanisms. The intermittently loud acoustic radiation is removed by a space–time localized control that alters a tearing-like vortex interaction which appears to lead to vortex coalescence for the uncontrolled jet.There are no proofs available concerning convergence to a global minimum of the radiated sound, and thus far the control applied to this turbulent jet has failed to achieve the same ~10 dB seen in previous studies of two-dimensional subsonic mixing layers. This is attributed to the greater…" @default.
• W1674788118 created "2016-06-24" @default.
• W1674788118 creator A5003369830 @default.
• W1674788118 date "2012-05-22" @default.
• W1674788118 modified "2023-09-26" @default.
• W1674788118 title "Adjoint-based control of turbulent jet noise" @default.
• W1674788118 cites W1480105993 @default.
• W1674788118 cites W1507478338 @default.
• W1674788118 cites W1521195322 @default.
• W1674788118 cites W1525114282 @default.
• W1674788118 cites W1545439678 @default.
• W1674788118 cites W1550555215 @default.
• W1674788118 cites W1572591577 @default.
• W1674788118 cites W1607071030 @default.
• W1674788118 cites W1631665119 @default.
• W1674788118 cites W1633869374 @default.
• W1674788118 cites W1637376309 @default.
• W1674788118 cites W1964876149 @default.
• W1674788118 cites W1965756459 @default.
• W1674788118 cites W1966099108 @default.
• W1674788118 cites W1966158133 @default.
• W1674788118 cites W1966359670 @default.
• W1674788118 cites W1968317884 @default.
• W1674788118 cites W1969674389 @default.
• W1674788118 cites W1972402222 @default.
• W1674788118 cites W1979579869 @default.
• W1674788118 cites W1981756274 @default.
• W1674788118 cites W1982676365 @default.
• W1674788118 cites W1983165369 @default.
• W1674788118 cites W1984726053 @default.
• W1674788118 cites W1985926034 @default.
• W1674788118 cites W1986113482 @default.
• W1674788118 cites W1991175662 @default.
• W1674788118 cites W1995239098 @default.
• W1674788118 cites W1997317636 @default.
• W1674788118 cites W1998127729 @default.
• W1674788118 cites W1999192945 @default.
• W1674788118 cites W2002616426 @default.
• W1674788118 cites W2004152688 @default.
• W1674788118 cites W2006430937 @default.
• W1674788118 cites W2007077624 @default.
• W1674788118 cites W2008195468 @default.
• W1674788118 cites W2015197832 @default.
• W1674788118 cites W2017336285 @default.
• W1674788118 cites W2017694272 @default.
• W1674788118 cites W2021039564 @default.
• W1674788118 cites W2021517931 @default.
• W1674788118 cites W2024843352 @default.
• W1674788118 cites W2025931426 @default.
• W1674788118 cites W2026443020 @default.
• W1674788118 cites W2030193957 @default.
• W1674788118 cites W2036466005 @default.
• W1674788118 cites W2036533194 @default.
• W1674788118 cites W2042247713 @default.
• W1674788118 cites W2043200311 @default.
• W1674788118 cites W2043291772 @default.
• W1674788118 cites W2044070003 @default.
• W1674788118 cites W2046413099 @default.
• W1674788118 cites W2047166888 @default.
• W1674788118 cites W2049955987 @default.
• W1674788118 cites W2050947747 @default.
• W1674788118 cites W2054077541 @default.
• W1674788118 cites W2063129713 @default.
• W1674788118 cites W2066111877 @default.
• W1674788118 cites W2067260262 @default.
• W1674788118 cites W2072980307 @default.
• W1674788118 cites W2074447412 @default.
• W1674788118 cites W2078644903 @default.
• W1674788118 cites W2082067558 @default.
• W1674788118 cites W2083449273 @default.
• W1674788118 cites W2086209713 @default.
• W1674788118 cites W2087458881 @default.
• W1674788118 cites W2089905752 @default.
• W1674788118 cites W2090110916 @default.
• W1674788118 cites W2092566323 @default.
• W1674788118 cites W2095387898 @default.
• W1674788118 cites W2095702650 @default.
• W1674788118 cites W2098814095 @default.
• W1674788118 cites W2099551355 @default.
• W1674788118 cites W2104111591 @default.
• W1674788118 cites W2111405281 @default.
• W1674788118 cites W2111509581 @default.
• W1674788118 cites W2111980920 @default.
• W1674788118 cites W2112823474 @default.
• W1674788118 cites W2114207542 @default.
• W1674788118 cites W2117770205 @default.
• W1674788118 cites W2118381422 @default.
• W1674788118 cites W2119389101 @default.
• W1674788118 cites W2119881161 @default.
• W1674788118 cites W2121963809 @default.
• W1674788118 cites W2125355488 @default.
• W1674788118 cites W2125362379 @default.
• W1674788118 cites W2126315656 @default.
• W1674788118 cites W2129523625 @default.
• W1674788118 cites W2134387111 @default.
• W1674788118 cites W2134861405 @default.
• W1674788118 cites W2135002668 @default.
• W1674788118 cites W2135353663 @default.
• W1674788118 cites W2136160744 @default.
• W1674788118 cites W2146778222 @default.

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