Computational simulation of the radiating structure of a microwave from a pyramidal horn has been successfully accomplished.This simulation capability is de-veloped for plasma diagnostics based on a combination of thr...Computational simulation of the radiating structure of a microwave from a pyramidal horn has been successfully accomplished.This simulation capability is de-veloped for plasma diagnostics based on a combination of three-dimensional Maxwell equations in the time domain and the generalized Ohm’s law.The transverse electrical electromagnetic wave of the TE1,0 mode propagating through a plasma medium and transmitting from antenna is simulated by solving these governing equations.Numerical results were obtained for a range of plasma transport properties including electrical con-ductivity,permittivity,and plasma frequency.As a guided microwave passing through plasma of finite thickness,the reflections at the media interfaces exhibit substantial distortion of the electromagnetic field within the thin sheet.In radiating simulation,the edge diffraction at the antenna aperture is consistently captured by numerical so-lutions and reveals significant perturbation to the emitting microwave.The numerical solution reaffirms the observation that the depth of the plasma is a critical parameter for diagnostics measurement.展开更多
Hypersonic magneto-fluid-dynamic interaction has been successfully performed as a virtual leading-edge strake and a virtual cowl of a rectangular inlet.In a side-by-side experimental and computational study,the magnit...Hypersonic magneto-fluid-dynamic interaction has been successfully performed as a virtual leading-edge strake and a virtual cowl of a rectangular inlet.In a side-by-side experimental and computational study,the magnitude of the induced compression was found to depend on configuration and electrode placement.To better understand the interacting phenomenon the present investigation is focused on a direct current discharge at the leading edge of a cylindrical inlet for which validating experimental data is available.The present computational result is obtained by solving the magneto-fluid-dynamics equations at the low magnetic Reynolds number limit and using a nonequilibrium weakly ionized gas model based on the drift-diffusion theory.The numerical simulation provides a detailed description of the intriguing physics.After validation with experimental measurements,the computed results further quantify the effectiveness of a magneto-fluid-dynamic compression for a hypersonic cylindrical inlet.A minuscule power input to a direct current surface discharge of 8.14 watts per square centimeter of electrode area produces an additional compression of 6.7 percent for a constant cross-section cylindrical inlet.展开更多
文摘Computational simulation of the radiating structure of a microwave from a pyramidal horn has been successfully accomplished.This simulation capability is de-veloped for plasma diagnostics based on a combination of three-dimensional Maxwell equations in the time domain and the generalized Ohm’s law.The transverse electrical electromagnetic wave of the TE1,0 mode propagating through a plasma medium and transmitting from antenna is simulated by solving these governing equations.Numerical results were obtained for a range of plasma transport properties including electrical con-ductivity,permittivity,and plasma frequency.As a guided microwave passing through plasma of finite thickness,the reflections at the media interfaces exhibit substantial distortion of the electromagnetic field within the thin sheet.In radiating simulation,the edge diffraction at the antenna aperture is consistently captured by numerical so-lutions and reveals significant perturbation to the emitting microwave.The numerical solution reaffirms the observation that the depth of the plasma is a critical parameter for diagnostics measurement.
文摘Hypersonic magneto-fluid-dynamic interaction has been successfully performed as a virtual leading-edge strake and a virtual cowl of a rectangular inlet.In a side-by-side experimental and computational study,the magnitude of the induced compression was found to depend on configuration and electrode placement.To better understand the interacting phenomenon the present investigation is focused on a direct current discharge at the leading edge of a cylindrical inlet for which validating experimental data is available.The present computational result is obtained by solving the magneto-fluid-dynamics equations at the low magnetic Reynolds number limit and using a nonequilibrium weakly ionized gas model based on the drift-diffusion theory.The numerical simulation provides a detailed description of the intriguing physics.After validation with experimental measurements,the computed results further quantify the effectiveness of a magneto-fluid-dynamic compression for a hypersonic cylindrical inlet.A minuscule power input to a direct current surface discharge of 8.14 watts per square centimeter of electrode area produces an additional compression of 6.7 percent for a constant cross-section cylindrical inlet.
