The Effects of Rotation Point on Stall Flutter of an Aerofoil

ABSTRACT Tire-pavement interaction noise (TPIN) is one of the main sources of exterior noise produced by vehicles traveling at greater than 50 kph. The dominant frequency content is typically within 500–1500 Hz. Structural tire vibrations are among the principal TPIN mechanisms. In this work, the structure of the tire is modeled and a new wave propagation solution to find its response is proposed. Multiple physical effects are accounted for in the formulation. In an effort to analyze the effects of curvature, a flat plate and a cylindrical shell model are presented. Orthotropic and nonuniform structural properties along the tire's transversal direction are included to account for differences between its sidewalls and belt. Finally, the effects of rotation and inflation pressure are also included in the formulation. Modeled frequency response functions are analyzed and validated. In addition, a new frequency-domain formulation is presented for the computation of input tread pattern contact forces. Finally, the rolling tire's normal surface velocity response is coupled with a boundary element model to demonstrate the radiated noise at the leading and trailing edge locations. These results are then compared with experimental data measured with an on-board sound intensity system.

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Stall flutter and probabilistic fatigue life prediction for cascaded airfoils

10.2514/6.1998-1853 ◽

1998 ◽

Author(s):

Xiaoguang Li ◽

Sanford Fleeter

Keyword(s):

Fatigue Life ◽

Life Prediction ◽

Fatigue Life Prediction ◽

Stall Flutter

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Effects of Rotation on Blade Surface Heat Transfer: An Experimental Investigation

Volume 3: Heat Transfer; Electric Power; Industrial and Cogeneration ◽

10.1115/97-gt-188 ◽

1997 ◽

Cited By ~ 1

Author(s):

Roger W. Moss ◽

Roger W. Ainsworth ◽

Tom Garside

Keyword(s):

Thin Film ◽

Heat Transfer ◽

Experimental Investigation ◽

Turbine Blade ◽

Time History ◽

Surface Heat ◽

Blade Surface ◽

Surface Heat Transfer ◽

Effects Of Rotation ◽

Wake Passing

Measurements of turbine blade surface heat transfer in a transient rotor facility are compared with predictions and equivalent cascade data. The rotating measurements involved both forwards and reverse rotation (wake free) experiments. The use of thin-film gauges in the Oxford Rotor Facility provides both time-mean heat transfer levels and the unsteady time history. The time-mean level is not significantly affected by turbulence in the wake; this contrasts with the cascade response to freestream turbulence and simulated wake passing. Heat transfer predictions show the extent to which such phenomena are successfully modelled by a time-steady code. The accurate prediction of transition is seen to be crucial if useful predictions are to be obtained.

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Effects of rotation discipline on medical student grades in obstetrics and gynecology throughout the academic year

American Journal of Obstetrics and Gynecology ◽

10.1016/0002-9378(93)90284-p ◽

1993 ◽

Vol 169 (5) ◽

pp. 1215-1217 ◽

Cited By ~ 4

Author(s):

Alberto Manetta ◽

Edward Manetta ◽

Dennis Emma ◽

K.A. Keegan ◽

J.H. Williams

Keyword(s):

Medical Student ◽

Obstetrics And Gynecology ◽

Effects Of Rotation ◽

Student Grades ◽

Academic Year

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Numerical Simulation of Shock-stall Flutter of an Airfoil using the Navier-Stokes Equations

Journal of Fluids and Structures ◽

10.1006/jfls.1993.1036 ◽

1993 ◽

Vol 7 (6) ◽

pp. 595-609 ◽

Cited By ~ 2

Author(s):

K. Isogai

Keyword(s):

Numerical Simulation ◽

Stokes Equations ◽

Navier Stokes ◽

Navier Stokes Equations ◽

Stall Flutter ◽

Shock Stall

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Effects of rotation and ion incidence angle on sputter depth resolution in thin films of NiFe/Ta

Surface and Interface Analysis ◽

10.1002/sia.740190113 ◽

1992 ◽

Vol 19 (1-12) ◽

pp. 55-59 ◽

Cited By ~ 11

Author(s):

Matthias M. Henneberg ◽

Daryl J. Pocker ◽

Michael A. Parker

Keyword(s):

Thin Films ◽

Incidence Angle ◽

Depth Resolution ◽

Effects Of Rotation

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Detached Eddy Simulation of Transonic Rotor Stall Flutter Using a Fully Coupled Fluid-Structure Interaction

Volume 6: Structures and Dynamics, Parts A and B ◽

10.1115/gt2011-45437 ◽

2011 ◽

Cited By ~ 7

Author(s):

Hongsik Im ◽

Xiangying Chen ◽

Gecheng Zha

Keyword(s):

Stokes Equations ◽

Rotating Stall ◽

Rotor Blades ◽

Tip Clearance ◽

Weno Scheme ◽

Navier Stokes ◽

Detached Eddy Simulation ◽

Eddy Simulation ◽

Stall Flutter ◽

Fully Coupled

Detached eddy simulation of an aeroelastic self-excited instability, flutter in NASA Rotor 67 is conducted using a fully coupled fluid/structre interaction. Time accurate compressible 3D Navier-Stokes equations are solved with a system of 5 decoupled modal equations in a fully coupled manner. The 5th order WENO scheme for the inviscid flux and the 4th order central differencing for the viscous flux are used to accurately capture interactions between the flow and vibrating blades with the DES (detached eddy simulation) of turbulence. A moving mesh concept that can improve mesh quality over the rotor tip clearance was implemented. Flutter simulations were first conducted from choke to stall using 4 blade passages. Stall flutter initiated at rotating stall onset, grows dramatically with resonance. The frequency analysis shows that resonance occurs at the first mode of the rotor blade. Before stall, the predicted responses of rotor blades decayed with time, resulting in no flutter. Full annulus simulation at peak point verifies that one can use the multi-passage approach with periodic boundary for the flutter prediction.

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