Investigation on noise from shock/isotropic turbulence interaction using direct numerical simulation

Shi, Fangcheng; Gao, Zhenxun; Lee, Chun‐Hian

doi:10.1016/j.jsv.2020.115633

Cited by 5 publications

(2 citation statements)

References 43 publications

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“…The interaction between compressible turbulence and shock wave is a classical problem and has been investigated by many researchers using the linear interaction analysis (LIA) and direct numerical simulation (DNS) 8‐11 . It is found that the normal shock wave could increase the TKE, and there is an amplification limitation of about 2 times with the increase of Mach number in front of the shock wave 10 .…”

Section: Introductionmentioning

confidence: 99%

“…7 The interaction between compressible turbulence and shock wave is a classical problem and has been investigated by many researchers using the linear interaction analysis (LIA) and direct numerical simulation (DNS). [8][9][10][11] It is found that the normal shock wave could increase the TKE, and there is an amplification limitation of about 2 times with the increase of Mach number in front of the shock wave. 10 Sinha et al 12 adopted standard/realizable k-𝜖 turbulence model to simulate the interaction between homogeneous isotropic turbulence and a normal shock wave, and compared the variations of TKE and SDR across the shock wave with those obtained by the LIA and DNS.…”

Section: Introductionmentioning

confidence: 99%

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A correction for Reynolds‐averaged‐Navier–Stokes turbulence model under the effect of shock waves in hypersonic flows

Tian

Gao

Lee

2022

Numerical Methods in Fluids

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Studies on the unphysical increase of turbulent quantities for RANS simulation induced by shock waves in hypersonic flows are carried out. Numerical experiments on the hypersonic flow over a blunt body reveal that the phenomenon of unphysical increase of turbulent quantities across the detached shock wave is induced by the strain-rate-based production terms of the k-𝜔 and k-𝜔 SST turbulence models, which leads to the over-prediction of aerothermal prediction.While this phenomenon does not occur for Spalart-Allmaras (S-A) turbulence model because of its vorticity-based production term. In order to eliminate this unphysical phenomenon, and to maintain the accuracy of the original models for boundary layer and separation flows, a new correction method for the k-𝜔 and k-𝜔 SST models is proposed: by comparing the orders of magnitude between the strain-rate-based and vorticity-based production terms, the vorticity-based production term is used near the shock waves, while the original strain-rate-based production term is still used in other regions. Finally, the correction method is applied to turbulence and transition flows over blunt bodies, and the numerical results show that the correction method effectively eliminates the unphysical increase of turbulent quantities across shock waves and improves the accuracy of aerothermal and transition onset location prediction.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A correction for Reynolds‐averaged‐Navier–Stokes turbulence model under the effect of shock waves in hypersonic flows

Tian

Gao

Lee

2022

Numerical Methods in Fluids

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Numerical investigation of shock-turbulent mixing layer interaction and shock-associated noise

2021

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Direct numerical simulation of shock-turbulent mixing layer interaction (STMLI) is conducted in this paper to study the influence of shock-turbulent interaction (STI) on the turbulence evolution and shock-associated noise. The results show that turbulent kinetic energy and pressure fluctuation around the interaction point of STI are both first increased and then reduced to a smaller value than that in the fully developed region of the turbulent mixing layer, while the Reynolds-stress anisotropy at the upper edge of STMLI is changed under the compression–expansion effect induced by the distorted shock tip and the reflected expansion wave. Additionally, it is found that shock-associated noise would increase the overall sound pressure level (OASPL) and amplify the high-frequency noise at the upstream observers. By applying the shock-leakage theory, the turbulence scale analysis, and the spectrum analysis, two generation mechanisms of shock-associated noise are identified: first, the influence of turbulence on the shock wave results in the shock unsteady movement, which generates a sound wave with cylindrical wave front; second, STI decreases the turbulence scale and increases the pressure fluctuation in the high-frequency band so as to strengthen the small-scale turbulence to radiate out more high-frequency noise. Finally, the shock strength effect on shock-associated noise is explored, and the shock-associated noise reduction is observed when decreasing the shock strength. By converting the OASPL difference to the equivalent acoustic pressure difference, a linear correlation between the shock-associated noise source strength and the shock strength is found.

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Nonlinear generation of sound and mean pressure drop in shock–shear interaction

2023

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Interactions of shear fluctuations with shock waves are ubiquitous in high-speed flow applications from scramjet propulsion to cosmic events like supernovae explosions. It also serves as a fundamental building block for the study of shock-turbulence interaction. In this work, we study the nonlinear effects in pressure arising due to the interaction of a normal shock with a two-dimensional shear wave. It employs the weakly nonlinear framework (WNLF) developed recently for vorticity amplification by Thakare et al. (Thakare, JFM, 2022). The analysis includes the effect of inter-modal interactions that is neglected in the widely used linear interaction analysis (LIA) of shock-turbulence interaction. It is found that the deformation of the shock wave and the fluctuation mass flux normal to the shock contribute to the dominant physical mechanisms responsible for the observed nonlinearities. Interestingly, the WNLF predicts a drop in mean pressure behind the shock due to second-order intermodal interaction, which is consistent with the well-established results by Lele (Lele, POF, 1992) at low Mach numbers and brings out additional effects of shock deformation that are important at higher Mach numbers. We extend the WNLF to three-dimensional interaction of homogeneous isotropic turbulence with a normal shock. Comparison with existing Direct Numerical Simulation (DNS) data shows good agreement for low turbulent Mach numbers which is a significant improvement over the prediction capability of LIA. We also compute the dilatation fields from WNLF and use them to distinguish between the acoustic and non-acoustic components of the second-order pressure fluctuations generated by the shock wave.

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Investigation on noise from shock/isotropic turbulence interaction using direct numerical simulation

Cited by 5 publications

References 43 publications

A correction for Reynolds‐averaged‐Navier–Stokes turbulence model under the effect of shock waves in hypersonic flows

A correction for Reynolds‐averaged‐Navier–Stokes turbulence model under the effect of shock waves in hypersonic flows

Numerical investigation of shock-turbulent mixing layer interaction and shock-associated noise

Nonlinear generation of sound and mean pressure drop in shock–shear interaction

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