Noise generation by a rotating blade row in an infinite annulus

1971 ◽  
Author(s):  
J. LORDI
Keyword(s):  
Noise Generation ◽  
Rotating Blade ◽  
Blade Row

Discrete Frequency Noise Generation From an Axial Flow Fan Blade Row

1970 ◽  
Vol 92 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Ramani Mani
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Acoustic Energy ◽  
Frequency Noise ◽  
Noise Generation ◽  
Two Dimensional ◽  
Axial Flow Fan ◽  
Fan Noise ◽  
Blade Row ◽  
Fan Blade

An analysis is presented which treats the noise generation from an axial flow fan row by given forces including the effects of a moving medium. The linearization of Euler’s equations to yield tractable problems for fan noise is discussed. The three-dimensional problem is decomposed into several two-dimensional problems. Finally, full details are given of a two-dimensional analysis to predict the amounts of acoustic energy, at the blade passing frequency and its harmonics, radiated up and downstream of a blade row due to its interaction with a neighboring row.

The interaction between a high-frequency gust and a blade row

1992 ◽  
Vol 241 ◽  
pp. 261-289 ◽  
Author(s):  
N. Peake
Keyword(s):  
Flat Plates ◽  
Rotating Blade ◽  
Reduced Frequency ◽  
Blade Row ◽  
Method Of Solution ◽  
Physical Insight ◽  
Formal Limit ◽  
Underlying Mechanisms ◽  
High Level ◽  
Unsteady Lift

The ingestion of convected vorticity by a high-solidity rotating blade row is a potent noise source in modern aeroengines, due largely to the high level of mutual aerodynamic interactions between adjacent blades. In order to model this process we solve the problem of determining the unsteady lift on an infinite cascade of finite-chord flat plates due to an incident vorticity wave. The method of solution is the Wiener–Hopf technique, and we consider the case of the reduced frequency, Ω, being large, allowing application of asymptotic analysis in the formal limit Ω → ∞. This approach yields considerable simplification, both in allowing the truncation of an infinite reflection series to just two terms, and in allowing algebraic expressions for the Wiener–Hopf split functions to be found. The unsteady lift distribution is derived in closed form, and the accuracy of the asymptotic Wiener–Hopf factorization demonstrated for even modest values of Ω by comparison with exact (but less tractable) methods. Our formulae can easily be incorporated into existing noise prediction codes: the advantage of our scheme is that it handles a regime in which conventional numerical approaches become unwieldy, as well as providing significant physical insight into the underlying mechanisms.

scholarly journals NUMERICAL SIMULATION OF THE ACOUSTIC WAVE REFLECTION FROM A ROTATING BLADE ROW

2018 ◽  
pp. 5-15 ◽  
Author(s):  
Nikolay Shuvaev ◽  
◽  
Aleksandr Siner ◽  
Nikita Bolshagin ◽  
Ruslan Kolegov ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Acoustic Wave ◽  
Wave Reflection ◽  
Rotating Blade ◽  
Blade Row

Fan Compressor Noise Reduction

1969 ◽  
Author(s):  
M. J. Benzakein ◽  
S. B. Kazin
Keyword(s):  
Noise Reduction ◽  
Pure Tone ◽  
Potential Interaction ◽  
Row Spacing ◽  
Noise Generation ◽  
Analytical Treatment ◽  
Blade Row ◽  
Compressor Design ◽  
Reduction Methods ◽  
Aerodynamic Parameters

A study of various fan/compressor noise reduction methods is presented. The analytical treatment of the basic mechanisms of fan/compressor noise generation is described. The results are presented in parametric form and indicate the effects of fan/compressor design, number of blades, vane/blade ratio, aerodynamic parameters, and blade row spacing on pure tone noise reduction. These results are based on nonsteady aerodynamic treatment of wake and potential interaction effects and theoretical extensions of spinning mode theories.

The Unsteady Response of a Blade Row From Measurements of the Time-Mean Total Pressure

1973 ◽  
Author(s):  
R. E. Henderson
Keyword(s):  
Experimental Data ◽  
Theoretical Analysis ◽  
Total Pressure ◽  
Theoretical Data ◽  
Two Dimensional ◽  
Interference Effects ◽  
Experimental Procedure ◽  
Rotating Blade ◽  
Reduced Frequency ◽  
Blade Row

An experimental procedure is described which permits the unsteady response of a rotating blade row to spatial variations in its inlet flow to be determined from measurements of the time-mean total pressure. This procedure has been employed to determine the unsteady circulation of a non-lifting rotor as a function of reduced frequency for two values of space-chord ratio. Comparisons of these experimental data are made with a recent theoretical analysis of the indirect or design problem of unsteady lift in a moving two-dimensional cascade. Both the experimental and theoretical data are shown to exhibit the same trends with variations in space-chord ratio and reduced frequency. These results demonstrate that the unsteady blade interference effects are significant, and that the representation of the unsteady response of a turbomachine blade row as an isolated airfoil is not valid for reduced frequencies less than 1.2.

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