A new approximation of the dispersion relations occurring in the sound-attenuation problem of turbofan aircraft engines
Journal Title: INCAS BULLETIN - Year 2011, Vol 3, Issue 4
Abstract
The dispersion relations, appearing in the analysis of the stability of a gas flow in a straight acoustically-lined duct with respect to perturbations produced by a time harmonic source, beside the wave number and complex frequency contain the solution of a boundary value problem of the Pridmore-Brown equation depending on the wave number and frequency. For this reason, in practice the dispersion relations are rarely simple enough for carried out the zeros. The determination of zeros of these dispersion relations is crucial for the prediction of the perturbation attenuation or amplification. In this paper an approximation of the dispersion relations is given. Our approach preserves the general character of the mean flow, the general Pridmore-Brown equation and it’s only in the shear flow that we replace the exact solution of the boundary value problem with its Taylor polynomial approximate. In this way new approximate dispersion relations are obtained which zero’s can be found by computer.
Authors and Affiliations
Stefan BALINT, Agneta M. BALINT, Mirela DARAU, Robert SZABO
Keywords
Related Articles
- EP ID EP119326
- DOI 10.13111/2066-8201.2011.3.4.2
- Views 374
- Downloads 0
Sammon mapping for preliminary analysis in Hyperspectral Imagery
The main goal of this paper is to present the implementation of the Sammon algorithm developed for finding N points in a lower m-dimensional subspace, where the original points are from a high n-dimensional space. This m...
Flight Control System Design and Analysis of a Light Sport Aircraft with Emphasis on Multibody Dynamics and Aerodynamic Analysis
The present contribution is a companion paper of [9] which presents a preliminary design of the flight control system of a Light Sport Aircraft (based on previous wind tunnel analysis), validation process, aerodynamic si...
Numerical simulation of K-, N- and O-regime boundary-layer transition at early nonlinear stage
Boundary layer transition is usually associated with the amplification and breakdown of three-dimensional waves (3D waves). However, the details of the development of 3D waves in different transition regimes are not well...
Study of natural and forced heat transfer coefficients on a vertical heated plate
Infrared thermography measurement technique is a methodology which detects infrared energy emitted from an object, converts it to temperature, and displays images of temperature distribution. It is a powerful non-invasiv...
Runway incursions – clear and constant danger
Runway safety plays an important role in aviation industry. This paper deals with runway safety – runway incursion as a serious safety concern. Focusing attention on this issue is necessary due to many collisions with a...