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Theoretical determination of nozzle admittances using a finite element approachA finite element method is used to predict the admittances of axisymmetric nozzles. It is assumed that the flow in the nozzle is isentropic and irrotational, and the disturbances are small so that linear analyses apply. An approximate, two dimensional compressible model is used to describe the steady flow in the nozzle. The propagation of acoustic disturbances is governed by the complete linear wave equation. The differential form of the acoustic equation is transformed to an integral equation using Galerkin's method, and Green's theorem is applied so that the acoustic boundary conditions can be introduced through the boundary residuals. A two-dimensional FEM using linear elements is used to solve the acoustic equation. A one dimensional FEM is also used to solve the reduced equation of Crocco, and the solution verifies the sufficiency of the boundary residual formulation. Comparison between computed admittances and experimental data is shown to be quite good.
Document ID
19800035109
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Sigman, R. K.
(Georgia Inst. of Tech. Atlanta, GA, United States)
Zinn, B. T.
(Georgia Institute of Technology Atlanta, Ga., United States)
Date Acquired
August 10, 2013
Publication Date
January 1, 1980
Subject Category
Aerodynamics
Report/Patent Number
AIAA PAPER 80-0085
Meeting Information
Meeting: Aerospace Sciences Meeting
Location: Pasadena, CA
Start Date: January 14, 1980
End Date: January 16, 1980
Sponsors: American Institute of Aeronautics and Astronautics
Accession Number
80A19279
Funding Number(s)
CONTRACT_GRANT: NSG-3036
Distribution Limits
Public
Copyright
Other

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