Method of Unsteady Aerodynamic Forces Approximation for Aeroservoelastic Interactions

2002 ◽  
Vol 25 (5) ◽  
pp. 985-987 ◽  
Author(s):  
Iulian Cotoi ◽  
Ruxandra M. Botez
Keyword(s):  
Aerodynamic Forces ◽  
Unsteady Aerodynamic

Control of Unsteady Aerodynamic Forces

1990 ◽  
Author(s):  
Chih-Ming Ho ◽  
Ismet Gursul ◽  
Chiang Shih ◽  
Hank Lin ◽  
Mario Lee
Keyword(s):  
Aerodynamic Forces ◽  
Unsteady Aerodynamic

Unsteady Aerodynamic Forces Measured on a Fluttering Profile

2014 ◽  
Author(s):  
Igor Zolotarev ◽  
Václav Vlček ◽  
Jan Kozánek
Keyword(s):  
Mach Number ◽  
Flow Field ◽  
Degrees Of Freedom ◽  
Air Flow ◽  
Optical Measurements ◽  
Energy Contribution ◽  
Aerodynamic Forces ◽  
Unsteady Aerodynamic ◽  
New Information ◽  
Drag And Lift

The study presents evaluation of optical measurements of the air flow field near the fluttering profile NACA0015 with two-degrees of freedom, Mach number of the flutter occurrence were M=0.21 and M=0.45. Aerodynamic forces (drag and lift components) were evaluated independently on the upper and lower surfaces of the profile. Using the mentioned decomposition, the new information about mechanism of flutter properties was obtained. The forces on the upper and lower surfaces are phase shifted and are partially eliminated as a result of the circulation around the profile. The cycle changes of these forces cause the permanent energy contribution from the airflow to the vibrating system.

Fractional calculus - A new approach to modeling unsteady aerodynamic forces

1991 ◽  
Author(s):  
RONALD BAGLEY ◽  
DAVID SWINNEY ◽  
KENNETH GRIFFIN
Keyword(s):  
Fractional Calculus ◽  
Aerodynamic Forces ◽  
New Approach ◽  
Unsteady Aerodynamic

scholarly journals Aerodynamic Detuning Analysis of an Unstalled Supersonic Turbofan Cascade

1986 ◽  
Vol 108 (1) ◽  
pp. 60-67 ◽  
Author(s):  
D. Hoyniak ◽  
S. Fleeter
Keyword(s):  
Flow Field ◽  
Leading Edge ◽  
Rotor Blades ◽  
Driving Mechanism ◽  
Aeroelastic Stability ◽  
Aerodynamic Forces ◽  
Unsteady Aerodynamic ◽  
Influence Coefficients ◽  
Blade Row ◽  
The Stability

A new, and as yet unexplored, approach to passive flutter control is aerodynamic detuning, defined as designed passage-to-passage differences in the unsteady aerodynamic flow field of a rotor blade row. Thus, aerodynamic detuning directly affects the fundamental driving mechanism for flutter, i.e., the unsteady aerodynamic forces and moments acting on individual rotor blades. In this paper, a model to demonstrate the enhanced supersonic unstalled aeroelastic stability associated with aerodynamic detuning is developed. The stability of an aerodynamically detuned cascade operating in a supersonic inlet flow field with a subsonic leading edge locus is analyzed, with the aerodynamic detuning accomplished by means of nonuniform circumferential spacing of adjacent rotor blades. The unsteady aerodynamic forces and moments on the blading are defined in terms of influence coefficients in a manner that permits the stability of both a conventional uniformly spaced rotor configuration as well as the detuned nonuniform circumferentially spaced rotor to be determined. With Verdon’s uniformly spaced Cascade B as a baseline, this analysis is then utilized to demonstrate the potential enhanced aeroelastic stability associated with this particular type of aerodynamic detuning.

On the Unsteady Aerodynamic Forces Acting on a Formula Car in a Wind Gust

2009 ◽  
Author(s):  
Makoto Tsubokura ◽  
Takuji Nakashima ◽  
Yoshihiro Sasaki ◽  
Kozo Kitoh
Keyword(s):  
Wind Gust ◽  
Aerodynamic Forces ◽  
Unsteady Aerodynamic

Unsteady Aerodynamic Forces and Aeroelastic Response for External Store of an Aircraft

1998 ◽  
Vol 35 (5) ◽  
pp. 678-687 ◽  
Author(s):  
Deman Tang ◽  
Earl H. Dowell
Keyword(s):  
Aerodynamic Forces ◽  
Aeroelastic Response ◽  
Unsteady Aerodynamic

Unsteady Aerodynamic Forces on Vibrating Annular Cascade Blades: Cross-Validation of the Linear Unsteady CFD Calculations Using the TVD Scheme and the Double Linearization Theory

2002 ◽  
Author(s):  
Nobuhiko Yamasaki ◽  
Masaaki Hamabe ◽  
Masanobu Namba
Keyword(s):  
Numerical Calculation ◽  
Delta Function ◽  
Point Of View ◽  
Tvd Scheme ◽  
Aerodynamic Forces ◽  
Unsteady Aerodynamic ◽  
Precise Calculation ◽  
Computational Resources ◽  
Volume Method ◽  
Annular Cascade

The paper presents the formulation to compute numerically the unsteady aerodynamic forces on the vibrating annular cascade blades. The formulation is based on the finite volume method, the type, and the TVD scheme, following the UPACS code developed by NAL, Japan. By applying the TVD scheme to the linear unsteady calculations, the precise calculation of the peak of unsteady aerodynamic forces at the shock wave location like the delta function singularity becomes possible without empirical constants. As a further feature of the present paper, results of the present numerical calculation are compared with those of the double linearization theory (DLT), which assumes small unsteady and steady disturbances but the unsteady disturbances are much smaller than the steady disturbances. Since DLT requires far less computational resources than the present numerical calculation, the validation of DLT is quite important from the engineering point of view. Under the conditions of small steady disturbances, a good agreement between these two results is observed, so that the two codes are cross-validated. The comparison also reveals the limitation on the applicability of DLT.

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