## Abstract

The problem of sound propagation in uniform ducts is examined using the Euler equations. First, a numerical spatial marching technique is examined for the case of no mean flow. The technique uses an initial value formulation. It is found that the scheme is stability limited, in agreement with previous results obtained using the Helmholtz equation. Also duct mode analysis is performed and the following is observed. When the mean flow in the duct is treated as isentropic, the solutions agree with existing solutions. However, this implies no pressure gradient for the mean flow in the streamwise direction. If a mean pressure gradient is imposed, it is found that the lowest mode attenuates as it propagates against the flow direction. It is also found that the same mode grows due to an instability, if it propagates downstream. This instability is related to combustion instability.

Original language | British English |
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Pages (from-to) | 1088-1094 |

Number of pages | 7 |

Journal | AIAA Journal |

Volume | 24 |

Issue number | 7 |

DOIs | |

State | Published - Jul 1986 |