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Abstract <p>The present study numerically investigates the effect of the external chamfer at the cavity mouth on the flow oscillation features of Hartmann whistle with the Helmholtz resonator. The important parameters that effect the flow oscillation of the Hartmann whistle are the stand-off distance, cavity geometry, nozzle pressure ratio, etc. The simulations are carried out for different external chamfer values of 15°, 30°, and 45° and compared the flow/shock oscillation features of the conventional Hartmann whistle at the same external chamfer angle. Computations show that the mass flow rate amplitude of Helmholtz resonators with 30° and 45° chamfers is higher than that of conventional non-chamfer resonator. Also, the fundamental frequencies of all cases increases slightly than without external chamfer. This shows that resonance is intensified by the presence of chamfer, resulting in higher sound pressure levels of chamfered whistles.</p>

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Effect of External Chamfer on the Performance of a Hartmann Whistle with a Helmholtz Resonator

  • 期刊论文

  • 发表日期：

    2026年6月29日

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  • Yong Son Jong,
  • Chol Jin Jon,
  • Jong Ryol Kim

摘要

Abstract

The present study numerically investigates the effect of the external chamfer at the cavity mouth on the flow oscillation features of Hartmann whistle with the Helmholtz resonator. The important parameters that effect the flow oscillation of the Hartmann whistle are the stand-off distance, cavity geometry, nozzle pressure ratio, etc. The simulations are carried out for different external chamfer values of 15°, 30°, and 45° and compared the flow/shock oscillation features of the conventional Hartmann whistle at the same external chamfer angle. Computations show that the mass flow rate amplitude of Helmholtz resonators with 30° and 45° chamfers is higher than that of conventional non-chamfer resonator. Also, the fundamental frequencies of all cases increases slightly than without external chamfer. This shows that resonance is intensified by the presence of chamfer, resulting in higher sound pressure levels of chamfered whistles.