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Liu R.-B.,Xiamen University | Liu R.-B.,Fujian Key Laboratory of Plasma and Magnetic Resonance | Niu Z.-G.,Aerodynamics Research Institute | Wang M.-M.,Xiamen University | And 4 more authors.
Gongcheng Lixue/Engineering Mechanics | Year: 2016

To investigate the control effect of Spark Discharge Plasma Jets (SPJs) on the aerodynamic moments of a wing, SPJ generators were used for active flow control experimental study on an NACA0021 straight wing model. The location of SPJ generators along the chord of the airfoil, the jet flow direction relative to the chord, and the driving voltage parameters were changed to research the control effect and mechanism of SPJ generators on the aerodynamic moments of a wing model. The aerodynamic moments were measured with a six-component balance at a wind speed of 20 m/s. Two SPJ generators, arranged near the leading edge, reduced the rolling moment coefficient by a maximum of 0.0024 for angles of attack -4°~10°, but increased the rolling moment coefficient by a maximum of 0.0021 for angles of attack 12°~16°. The yaw moment coefficient was reduced by a maximum of 0.00097. The results show that aerodynamic moments control of wings can be realized using SPJs. The control effect of SPJs on the aerodynamic moments is changeable by adjusting the driving voltage frequency and the jet flow direction relative to the chord. © 2016, Engineering Mechanics Press. All right reserved. Source


Qu X.,Xiamen University | Qu X.,Fujian Key Laboratory of Plasma and Magnetic Resonance | Guo D.,Xiamen University | Cao X.,Shanghai JiaoTong University | And 2 more authors.
Sensors | Year: 2011

Reducing the acquisition time for two-dimensional nuclear magnetic resonance (2D NMR) spectra is important. One way to achieve this goal is reducing the acquired data. In this paper, within the framework of compressed sensing, we proposed to undersample the data in the indirect dimension for a type of self-sparse 2D NMR spectra, that is, only a few meaningful spectral peaks occupy partial locations, while the rest of locations have very small or even no peaks. The spectrum is reconstructed by enforcing its sparsity in an identity matrix domain with ℓp (p = 0.5) norm optimization algorithm. Both theoretical analysis and simulation results show that the proposed method can reduce the reconstruction errors compared with the wavelet-based ℓ1 norm optimization. © 2011 by the authors; licensee MDPI, Basel, Switzerland. Source


Liu R.,China Aerodynamics Research And Development Center | Liu R.,Xiamen University | Liu R.,Fujian Key Laboratory of Plasma and Magnetic Resonance | Niu Z.,Aviation Industry Corporation of China | And 6 more authors.
Science China Technological Sciences | Year: 2015

Spark discharge plasma synthetic jets (SPJs) have been used for the active flow control study on an NACA 0021 straight-wing model in a wind tunnel. The model forces and moments were measured using a six-component sting balance at a 20 m/s wind speed. The aim was to explore the SPJ’s effect on airfoil aerodynamic by examining SPJ generators’ position along the chordwise and the jet flow direction about the chord. Near the wing leading edge, two SPJ generators raised the stall angle by 2° and increased the maximum lift coefficient by 9%. The drag coefficient was decreased by 33.1%, and the lift-drag ratio was increased by 104.2% at an angle of attack above 16°. The rolling-moment coefficient was modified by 0.002, and the yawing-moment coefficient was changed by 0.0007 at angles of attack in the range of 0°–16°. The results showed that SPJs can control wing aerodynamic forces at a high angle of attack and moments at a low angle of attack. © 2015 Science China Press and Springer-Verlag Berlin Heidelberg Source


Liu R.B.,China Aerodynamics Research And Development Center | Liu R.B.,Xiamen University | Liu R.B.,Fujian Key Laboratory of Plasma and Magnetic Resonance | Niu Z.G.,Aviation Industry Corporation of | And 6 more authors.
Science China Technological Sciences | Year: 2015

Spark discharge plasma synthetic jets (SPJs) have been used for the active flow control study on an NACA 0021 straight-wing model in a wind tunnel. The model forces and moments were measured using a six-component sting balance at a 20 m/s wind speed. The aim was to explore the SPJ’s effect on airfoil aerodynamic by examining SPJ generators’ position along the chordwise and the jet flow direction about the chord. Near the wing leading edge, two SPJ generators raised the stall angle by 2° and increased the maximum lift coefficient by 9%. The drag coefficient was decreased by 33.1%, and the lift-drag ratio was increased by 104.2% at an angle of attack above 16°. The rolling-moment coefficient was modified by 0.002, and the yawing-moment coefficient was changed by 0.0007 at angles of attack in the range of 0°–16°. The results showed that SPJs can control wing aerodynamic forces at a high angle of attack and moments at a low angle of attack. © 2015, Science China Press and Springer-Verlag Berlin Heidelberg. Source


Liu R.,Xiamen University | Liu R.,Fujian Key Laboratory of Plasma and Magnetic Resonance | Liu R.,Aeronautical Science and Technology Key Laboratory for Flight Simulation | Wang M.,Xiamen University | And 8 more authors.
Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica | Year: 2016

An air supplementing type plasma synthetic jet (ASPSJ) generator has been developed in this paper. A one-way check valve, increasing the air refill supply at the recover stage, is connected to a typical spark discharge plasma synthetic jet (PSJ) generator. The ASPSJ improves jet flow continuity of typical PSJ and can get higher energy synthetic jet. The effect of different valves on the maximum average jet flow speed is researched with different electric parameters. The best electric parameters for the highest synthetic jet flow speed are obtained by orthogonal test. For the test ASPSJ generators, the best loading voltage frequency, amplitude, and duty cycle are 150 Hz, 50 kV and 15%. The results show that ASPSJ strengthens the maximum average jet flow speed by above 20%. The best actuation frequency is increased, and the actuation frequency bandwidth for maximum jet flow speed enlarges from one point to 100 Hz. Better airflow control effect can be expected by ASPSJ in wind tunnel tests. The research results provide guidance for further active flow control application. © 2016, Press of Chinese Journal of Aeronautics. All right reserved. Source

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