The Investigation of Blowing Parameter Similarity for Controlling Flow Separation over Control Surface

2011 ◽  
Author(s):  
Y. K. Wang ◽  
P. Wu ◽  
X. Y. Deng ◽  
W. L. Zheng ◽  
Y. H. Zhang ◽  
...  
Keyword(s):  
Flow Separation ◽  
Control Surface ◽  
Blowing Parameter

Measurements of Bluff Body Wake Flow Around a Conformable Flow Control Surface

2003 ◽  
Author(s):  
David A. Ericson ◽  
Michael Jonson ◽  
Gary Koopmann
Keyword(s):  
Flow Control ◽  
Vortex Shedding ◽  
Flow Separation ◽  
Bluff Body ◽  
The Body ◽  
Control Surface ◽  
Periodic Flow ◽  
Two Dimensional ◽  
Trailing Edge ◽  
Shedding Frequency

The vortex street is a unique type of unsteady flow separation seen commonly in flow over a bluff body with a characteristic periodic wake. A consequence of the periodic flow is that the drag and lift forces acting on the body also oscillate periodically. When the wake shedding frequency is near a structural frequency, flow induced resonance will occur. The continuing interest in the study of vortex street generation is propelled by the ever-present nature of these flows in a variety of applications including aerodynamics, hydrodynamics and underwater acoustics. Recent advances in material science and the development of high power density actuators have led to the study of adaptive structure technology wherein the vorticity of periodic flows can be actively controlled by changing the ‘bluffness’ or shape of the body. In this paper, the development and experimental testing of a two-dimensional shape-variable flow control surface are discussed in relation to the generation and manipulation of periodic flow separation. Two series of wind tunnel tests were designed to evaluate the potential of the morphing structure that replaced a section of the trailing edge of a symmetric airfoil. The test section successfully demonstrated a smooth transition between three prescribed trailing edge profiles ranging from sharp to blunt. Unsteady pressure spectra were measured near the trailing edge for three different shape profiles over a range of speeds between 50 and 110 ft/s. The measured pressure spectra amplitudes were compared to previously-published surface pressure spectra of a similar, two-dimensional, blunt edge foil. A second set of tests was performed to measure the resulting flow field in the direction transverse to the flow and downstream from the airfoil. Velocity measurements were made using a traversing hot-wire probe at three trailing edge configurations and speeds of 50, 70 and 90 ft/s. The corresponding Reynolds number based on wake thickness ranged from 3.9–9.8 × 104. Measured vortex shedding frequencies varied between approximately 50 to 130 Hz at the different trailing edge profiles. This type of change in the vortex shedding frequency can be used to reduce flow-induced vibration and its associated noise generation by avoiding shedding frequencies at operating speeds that coincide with airfoil resonances.

Application of Pulsed Blowing Technique in High-Lift Control Surface Design

2012 ◽  
Vol 482-484 ◽  
pp. 121-125
Author(s):  
Peng Wu ◽  
Xue Ying Deng ◽  
Yan Kui Wang
Keyword(s):  
Flow Separation ◽  
Deflection Angle ◽  
Leading Edge ◽  
Control Surface ◽  
Control Technique ◽  
High Lift ◽  
Surface Design ◽  
Aerodynamic Efficiency ◽  
Lift Control ◽  
Control Surfaces

Because the flight performance of aircraft is so dependent on aerodynamic efficiency of control surfaces, it is very important to eliminate the flow separation over the control surfaces at high deflection angle in order to keep the aircraft having good flight capability, especially for the modern aircraft with tailless aerodynamic configuration. A novel flow control technique to eliminate flow separation of control surface at high deflection angle and creat high lift increment by pulsed blowing at leading edge of control surface is discussed in this paper. The performance of lift enhancment of control surface which used this technique is investigated, and based on the zonal analysis of pulsed frequency, the control characteristic of this technique is also discussed.

Characterization of carbides in M50NiL

1991 ◽  
Vol 49 ◽  
pp. 606-607
Author(s):  
L. S. Lin ◽  
K. P. Gumz ◽  
A. V. Karg ◽  
C. C. Law
Keyword(s):  
Temperature Effects ◽  
Base Composition ◽  
Lattice Parameter ◽  
Control Surface ◽  
Carbide Formation ◽  
Particle Sizes ◽  
Low Carbon ◽  
Fee Structure ◽  
Heat Treated

Carbon and temperature effects on carbide formation in the carburized zone of M50NiL are of great importance because they can be used to control surface properties of bearings. A series of homogeneous alloys (with M50NiL as base composition) containing various levels of carbon in the range of 0.15% to 1.5% (in wt.%) and heat treated at temperatures between 650°C to 1100°C were selected for characterizations. Eleven samples were chosen for carbide characterization and chemical analysis and their identifications are listed in Table 1.Five different carbides consisting of M6C, M2C, M7C3 and M23C6 were found in all eleven samples examined as shown in Table 1. M6C carbides (with least carbon) were found to be the major carbide in low carbon alloys (<0.3% C) and their amounts decreased as the carbon content increased. In sample C (0.3% C), most particles (95%) encountered were M6C carbide with a particle sizes range between 0.05 to 0.25 um. The M6C carbide are enriched in both Mo and Fe and have a fee structure with lattice parameter a=1.105 nm (Figure 1).

Flow Separation Delay on NACA 4415 Airfoil Using Plasma Actuator Effect

2019 ◽  
Vol 12 (4) ◽  
pp. 180
Author(s):  
Harinaldi Harinaldi ◽  
Budiarso Budiarso ◽  
Fadli Cahya Megawanto ◽  
Riza Farrash Karim ◽  
Nely Toding Bunga ◽  
...  
Keyword(s):  
Flow Separation ◽  
Plasma Actuator

INVESTIGATION OF FLOW SEPARATION PROPAGATION ON PROPELLER BLADES BY THE TUFTS AND LIGHT SHEET TECHNIQUES

2009 ◽  
Vol 40 (1) ◽  
pp. 103-115
Author(s):  
V. E. Mosharov ◽  
A. A. Orlov ◽  
S. P. Ostroukhov ◽  
V. N. Radchenko
Keyword(s):  
Flow Separation ◽  
Light Sheet ◽  
Propeller Blades

Nonlinear response of airfoil section with control surface freeplay to gust loads

AIAA Journal ◽  
2000 ◽  
Vol 38 ◽  
pp. 1543-1557 ◽  
Author(s):  
Deman Tang ◽  
Denis Kholodar ◽  
Earl H. Dowell
Keyword(s):  
Nonlinear Response ◽  
Control Surface ◽  
Airfoil Section ◽  
Gust Loads

Nozzle flow separation

AIAA Journal ◽  
1998 ◽  
Vol 36 ◽  
pp. 1618-1625 ◽  
Author(s):  
G. L. Romine
Keyword(s):  
Flow Separation ◽  
Nozzle Flow
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