Numerical simulations of the steady and unsteady aerodynamic characteristics of a circulation control wing airfoil

2001 ◽  
Author(s):  
Yi Liu ◽  
Lakshmi Sankar ◽  
Robert Englar ◽  
Krishan Ahuja
Keyword(s):  
Numerical Simulations ◽  
Aerodynamic Characteristics ◽  
Circulation Control ◽  
Unsteady Aerodynamic ◽  
Wing Airfoil

Effect of Shock Wave Behavior on Unsteady Aerodynamic Characteristics of Oscillating Transonic Compressor Cascade

2021 ◽  
Author(s):  
Jiuliang Gan ◽  
Toshinori Watanabe ◽  
Takehiro Himeno
Keyword(s):  
Shock Wave ◽  
Aerodynamic Force ◽  
Aerodynamic Characteristics ◽  
Fast Response ◽  
Influence Coefficient ◽  
Compressor Cascade ◽  
Blade Vibration ◽  
Unsteady Pressure ◽  
Transonic Compressor ◽  
Unsteady Aerodynamic

Abstract The unsteady behavior of the shock wave was studied in an oscillating transonic compressor cascade. The experimental measurement and corresponding numerical simulation were conducted on the cascade with different shock patterns based on influence coefficient method. The unsteady pressure distribution on blade surface was measured with fast-response pressure-sensitive paint (PSP) to capture the unsteady aerodynamic force as well as the shock wave movement. It was found that the movement of shock waves in the neighboring flow passages of the oscillating blade was almost anti-phase between the two shock patterns, namely, the double shocks pattern and the merged shock pattern. It was also found that the amplitude of the unsteady pressure caused by the passage shock wave was very large under the merged shock pattern compared with the double shocks pattern. The stability of blade vibration was also analyzed for both shock patterns including 3-D flow effect. These findings were thought to shed light on the fundamental understanding of the unsteady aerodynamic characteristics of oscillating cascade caused by the shock wave behavior.

scholarly journals Aerodynamic Damping Characteristics of a Transonic Turbine Cascade

1999 ◽  
Author(s):  
Mizuho Aotsuka ◽  
Toshinori Watanabe ◽  
Yasuo Machida
Keyword(s):  
Phase Angle ◽  
Aerodynamic Force ◽  
Turbine Blades ◽  
Aerodynamic Characteristics ◽  
Influence Coefficient ◽  
Suction Surface ◽  
Aerodynamic Damping ◽  
Unsteady Aerodynamic ◽  
Design Case ◽  
Oscillation Instability

The unsteady aerodynamic characteristics of oscillating thin turbine blades were studied both experimentally and numerically to obtain the comprehensive knowledge on the aerodynamic damping of the blades operating in transonic flows. The experiment was carried out in a linear cascade tunnel by use of the influence coefficient method. The two flow conditions were adopted, namely, a near-design condition and an off-design condition with a higher back pressure. In the results for the near-design case, a strong vibration instability was observed in the positive side of the interblade phase angle. In the off-design case, however, the instability did not appear for almost all the interblade phase angles. A drastic change was found in the phase angle of unsteady aerodynamic force between the two cases, which change was a governing factor for the oscillation instability. Numerical simulation based on 2-D Euler equation revealed that the phase change came from the change in phase of the unsteady surface pressure across the shock impingement point on the blade suction surface in the off-design case. The numerical results also showed that the aerodynamic damping increased with increasing reduced frequency, and that the oscillation instability disappeared.

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