Suppression of the Higher-Order Azimuthal Mode Competition in an ${X}$ -Band Triaxial Klystron Amplifier With a Slotted Coaxial Waveguide

2020 ◽  
Vol 67 (3) ◽  
pp. 1215-1220 ◽  
Author(s):  
Jun Zhang ◽  
Wei Zhang ◽  
Dian Zhang ◽  
Jinchuan Ju ◽  
Huihuang Zhong
Keyword(s):  
Higher Order ◽  
Coaxial Waveguide ◽  
Mode Competition ◽  
Azimuthal Mode ◽  
X Band

Simultaneous measurement of the radial and azimuthal mode indices of a higher-order partially coherent vortex beam based on phase detection

2019 ◽  
Vol 44 (15) ◽  
pp. 3881 ◽  
Author(s):  
Jun Zeng ◽  
Xingyuan Lu ◽  
Leixin Liu ◽  
Xinlei Zhu ◽  
Chengliang Zhao ◽  
...  
Keyword(s):  
Simultaneous Measurement ◽  
Higher Order ◽  
Vortex Beam ◽  
Phase Detection ◽  
Azimuthal Mode ◽  
Partially Coherent ◽  
Coherent Vortex

Acoustic theory of the many-bladed contra-rotating propeller: analysis of the effects of blade sweep on wake interaction noise

2019 ◽  
Vol 868 ◽  
pp. 385-427 ◽  
Author(s):  
M. J. Kingan ◽  
A. B. Parry
Keyword(s):  
Special Functions ◽  
Higher Order ◽  
Stationary Points ◽  
Asymptotic Approach ◽  
Azimuthal Mode ◽  
Special Cases ◽  
Wake Interaction ◽  
Radiated Sound ◽  
Interior Points ◽  
Mode Order

An analytical model is presented for the wake interaction tones produced by a contra-rotating propeller. We re-cast the usual far-field radiation formulae as a double integral over a nominal propeller source annulus. Assuming that the number of blades on both propellers is large, we evaluate the integral asymptotically in terms of its leading-order contributions from interior stationary or boundary critical points which represent the specific locations on the propeller annulus that dominate the sound radiation. The asymptotic approach is powerful producing results in the form of one-line algebraic formulae that contain no integrals or special functions yet remain accurate. The asymptotics show that sweep is not necessarily beneficial and can cause the blade design to become critical for particular tones and directions in terms of a continuum of interior points distributed along a line on the propeller source annulus producing a higher-order result and thus an enhanced radiated sound field. The paper also shows how the interior points are completely consistent with the sub- or super-critical gust response of a swept blade. Tones with low and zero azimuthal mode order are treated as special cases and the asymptotics show that, as the mode order reduces, the radiated sound becomes concentrated around the flight axis where even higher-order solutions are possible, including rings and annuli of stationary points around the propeller annulus. Full numerical calculations confirm the accuracy of the asymptotic approach.

Higher order modes of the Ridged Coaxial Waveguide

2006 ◽  
Author(s):  
Maangeles Ruiz-Bernal ◽  
Maria Valverde-Navarro ◽  
George Goussetis ◽  
Jose-luis Gomez-Tornero ◽  
Alexandros Feresidis
Keyword(s):  
Higher Order ◽  
Coaxial Waveguide ◽  
Higher Order Modes
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