통합 검색 | Korea Science

전승;최해천
- 대한기계학회:학술대회논문집
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- 대한기계학회 2007년도 춘계학술대회B
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- pp.2753-2756
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- 2007
In the present study, we reduce the drag and lift fluctuations of the sphere by providing a linear proportional control. For this purpose, we measure the radial velocity along the centerline in the wake and provide blowing and suction at a part of sphere surface based on the measured velocity. Zero-net mass flow rate is satisfied during the control. This control is applied to the flow over a sphere at Re=300 and 425. We vary the sensing location at $0.8d{\leq}X_s{\leq}1.3d$ and find that the most effective sensing region coincides with the location at which minimum correlation between the lift and sensing-velocity directions occurs. As a result, the lift and drag fluctuations are significantly reduced.
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Kwon Oh Kuen;Kwon Jun Sik;Hwang Ho Jung;Kang Jeong Won
- 대한전자공학회:학술대회논문집
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- 대한전자공학회 2004년도 학술대회지
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- pp.787-791
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- 2004
We investigated field-effect ion-transport devices based on carbon nanotubes by using classical molecular dynamics simulations under applied external force fields, and we present model schematics that car be applied to the nanoscale data storage devices and unipolar ionic field-effect transistors. As the applied external force field is increased, potassium ions rapidly flow through the nanochannel. Under low external force fields, ther nal fluctuations of the nanochannels affect tunneling of the potassium ions whereas the effects of thermal fluctuations are negligible under high external force fields. Since the electric current conductivity increases when potassium ions are inserted into fullerenes or carbon nanotubes, the field effect due to the gate, which can modify the position of the potassium ions, changes the tunneling current between the drain and the source.
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