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61.
High-lift airfoil trailing edge separation control using a single dielectric barrier discharge plasma actuator 总被引:3,自引:0,他引:3
Control of flow separation from the deflected flap of a high-lift airfoil up to Reynolds numbers of 240,000 (15 m/s) is explored
using a single dielectric barrier discharge (DBD) plasma actuator near the flap shoulder. Results show that the plasma discharge
can increase or reduce the size of the time-averaged separated region over the flap depending on the frequency of actuation.
High-frequency actuation, referred to here as quasi-steady forcing, slightly delays separation while lengthening and flattening
the separated region without drastically increasing the measured lift. The actuator is found to be most effective for increasing
lift when operated in an unsteady fashion at the natural oscillation frequency of the trailing edge flow field. Results indicate
that the primary control mechanism in this configuration is an enhancement of the natural vortex shedding that promotes further
momentum transfer between the freestream and separated region. Based on these results, different modulation waveforms for
creating unsteady DBD plasma-induced flows are investigated in an effort to improve control authority. Subsequent measurements
show that modulation using duty cycles of 50–70% generates stronger velocity perturbations than sinusoidal modulation in quiescent
conditions at the expense of an increased power requirement. Investigation of these modulation waveforms for trailing edge
separation control similarly shows that additional increases in lift can be obtained. The dependence of these results on the
actuator carrier and modulation frequencies is discussed in detail. 相似文献
62.
Structural conversion and spin separation in Bis(ferrocenylethynyl)anthraquinones triggered by proton-coupled intramolecular electron transfer. 总被引:1,自引:0,他引:1
M Murata M Yamada T Fujita K Kojima M Kurihara K Kubo Y Kobayashi H Nishihara 《Journal of the American Chemical Society》2001,123(51):12903-12904
63.
H. Ishizuki T. Suhara M. Fujimura H. Nishihara 《Optical and Quantum Electronics》2001,33(7-10):953-961
We report picosecond all-optical switching in optical communication band using a LiNbO3 waveguide quasi-phase matched second-harmonic generation/difference-frequency generation device. Analysis based on the beam propagation method showed that 1 ps switching with 3.1% efficiency is feasible with 10 W peak control pulse power. Switching efficiency of ?22 dB was demonstrated using control pulses of 10 ps width and 2 W peak power. 相似文献
64.
This paper derives the owner’s optimal contract with a bonus-incentive and audit when the owner delegates the investment timing decision to a manager with private information on an investment project. The optimal solution not only unifies the previous studies, but also accounts for actual auditing systems in firms. 相似文献
65.
Inside Back Cover: Giant Hysteretic Single‐Molecule Electric Polarisation Switching above Room Temperature (Angew. Chem. Int. Ed. 41/2018) 下载免费PDF全文
66.
67.
Recently we introduced the “ice templating” method, a new method which allows the synthesis of nanoporous materials with unique morphology, such as microfibers and microhoneycombs. In this method, materials are synthesized by freezing their parent hydrosols or hydrogels unidirectionally. Ice crystals which grow within the precursor during freezing act as the template. Therefore, the template can be easily removed through simple thawing and drying, which is a unique and beneficial feature of this method. This paper will first describe the outline of this new method and next, the details about methods to control the dimensions of the materials obtained through it. Comments about the range of applicability of this method will also be provided. 相似文献
68.
69.
H Saji K Enoki T Tokui Y Yonekura Y Nishihara A Yokoyama K Torizuka 《Radioisotopes》1984,33(9):611-616
The quantitative measurement of regional blood flow and regional extravascular lung water, called for a design of 15O labeled water production and administration under continuous and constant flow. In our search for simple methodology, suitable for clinical routine facilities, two remote-controlled systems were designed and their applicability for continuous and constant infusion of H215O were tested. In system (A), H215O was prepared from C15O2 based on the fast exchange reaction between carbon dioxide and carbonic acid. In the system (B), the reaction of 15O2 with H2 using palladium as a catalyst was adopted. In the both systems, the radioactivity level of the infusate was kept constant by using a buffer reservoir. Clinical applicability of both fully automated systems for the production of sterile H215O at a continuous and constant rate was discussed. Namely, system (A), being very simple seems more suitable for any closely located facility but system (B) is more suited for the production of higher radioactivity. 相似文献
70.