Novel Approach to the Calculation of Flow-acoustic Phenomena
Sound radiation from an open pipe with flow is a common problem in flow acoustics. In automotive applications it naturally appears at tailpipes of exhaust systems and air outlets of ventilation systems. In this article, the Virtual Vehicle Research Center presents a new approach to reduce the complexity of flow noise calculations.
Limits of Existing Techniques
Sound radiation from an open pipe is affected by several flow-acoustic phenomena: convection by the mean flow of fluid, diffraction at the edge of the pipe opening, and refraction in the mixing region of the flow in front of the opening. Numerical calculations taking into account these phenomena are very often associated with high computational costs, especially in cases of strong coupling between main flow and acoustic waves. An example of such coupling is the vortex-sound interaction at the sharp trailing edge of the pipe. The vortices shed from the edge are partly amplified by the incoming sound wave inside the pipe and, thus,...
The research work of Drasko Masovic has been funded by the European Commission within the ITN Marie Curie Action Project “Batwoman” under the 7th Framework Program (EC grant agreement No. 605867). The authors acknowledge the financial support of the Comet K2 — Competence Centers for Excellent Technologies Program of the Austrian Federal Ministry for Transport, Innovation and Technology (bmvit), the Federal Ministry for Digital, Business and Enterprise (bmdw), the Austrian Research Promotion Agency (FFG), the Province of Styria and the Styrian Business Promotion Agency (SFG).
- Hornikx, M.; De Roeck, W.; Desmet W.: Flow and Geometrical Effects on Radiated Noise from Exhausts Computed by a Hybrid Extended Fourier PSTD Method. 17th AIAA/CEAS Aeroacoustics Conference, Portland (Oregon), 2011. DOI: https://doi.org/10.2514/6.2011-2844Google Scholar
- Masovic. D.: Sound Radiation from an Open Pipe with a Mean Flow. Graz, IEM KUG, Dissertation, 2017Google Scholar
- Masovic, D.; Nijman, E.; Rejlek, J.; Höldrich, R.: Towards a Boundary Condition for Convective Wave Equation and Sound Diffraction at a Trailing Edge Inside a Flow. In: Conference report, Daga 2017, Kiel, pp. 1301–1304Google Scholar