Numerical Study on the Sound Amplification of a T-Junction with Bias Flow

  • Lin Du
  • Mikael Karlsson
  • Mats Åbom
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 185)


This paper reports a numerical study on the aeroacoustic response of a rectangular T-junction with bias flow in the side-branch. The primary motivation of the present work is to study and explain the in recent experiments observed high sound amplification at small bias flows. The study is conducted by performing numerical simulation, which solves the 2D compressible linearized Navier-Stokes equations (LNSEs) in the frequency domain. The time averaged flow is first solved by using RANS along with a k-ε turbulence model. The overall agreement with the experimental acoustic 3-port scattering data is good. It is found that the base flow changes significantly with the presence of a small bias flow. Compared to the case with no bias flow, a strong shear layer is created along the downstream main duct by the mixed grazing-bias flow. For small bias flows (Mach-number < 0.02) this shear layers extends far downstream of the actual junction. This creates a region of vortex-sound interaction much larger than for the no bias flow case, which is the main explanation behind the large amplification.


Shear Layer Strouhal Number Power Ratio Acoustic Power Main Duct 
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Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  1. 1.The Marcus Wallenberg Laboratory for Sound and Vibration ResearchKTH-CCGEx, KTH-FLOWStockholmSweden

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