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Measurement of the Noise of Ducted Fans
The Journal of the Acoustical Society of America, 1956A proposed technique for measuring the noise of a ducted fan by means of a microphone placed inside the fan duct was evaluated by comparing results so obtained with those obtained by measuring the total sound energy radiated from the duct into a reverberation chamber. A suitable microphone windscreen was developed and was used to reduce the aerodynamic
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Journal of Applied Mechanics, 1958
Abstract A theory is outlined by means of which it is possible to design ducted fans directly and without having to choose any parameters in an arbitrary fashion. Optimum sizes and fan speeds are theoretically determined. The design of two fans, one having inlet guide vanes and the other of the low slip-stream-rotation type having NPL ...
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Abstract A theory is outlined by means of which it is possible to design ducted fans directly and without having to choose any parameters in an arbitrary fashion. Optimum sizes and fan speeds are theoretically determined. The design of two fans, one having inlet guide vanes and the other of the low slip-stream-rotation type having NPL ...
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Acoustic Isolation of Fans in Ducts
Proceedings of the Institution of Mechanical Engineers, 1966A method of reducing the sound power radiated downstream from axial flow fans is described and investigated. The normal parallel duct fan housing is replaced by a contoured arrangement. With one type of contour and the use of porous absorbent material the reduction in the downstream overall sound power level is 5 dB, that is, the total sound power is ...
A. W. Roberts, R. E. Luxton
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Impact of Bypass Duct Bifurcations on Fan Noise
Journal of Propulsion and Power, 2012The present work is concerned with the impact of bifurcations, i.e., extensions of the pylon inside the bypass duct, on fan tonal noise radiated by civil turbofan engines. The investigation is carried out on a typical configuration composed of a rotor–stator stage, a row of struts, and one upper and one lower bifurcation.
Holewa, Axel +2 more
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VENTI: Experimental controller for inline duct fan
2017 4th Experiment@International Conference (exp.at'17), 2017This demo exemplifies the use of a special built controller for an inline duct fan. This controller uses the temperature and humidity data, from the interior and exterior environment to implement programmable control strategies based on differential vapor pressure. The controller is able to operate the fan with variable velocity.
Paulo Abreu +5 more
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Broadband self-noise from a ducted fan
AIAA Journal, 1998This paper describes the prediction of broadband self noise from ducted fans. The source mechanism is assumed to be the interaction of the turbulent boundary layer with the trailing edges of the fan blades. The source levels are obtained from the measurements of self noise from isolated blades by Brooks, Pope and Marcolini and these are corrected to ...
Stewart A. L. Glegg, Cyrille Jochault
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A Note on the Design of Ducted Fans
Aeronautical Quarterly, 1951SummaryThe design of ducted fans, and the estimation of their performance for conditions other than those of the design, are usually based on the equations of the so-called strip-theory. Existing methods of solution invariably employ some form of iteration which is more or less rapidly convergent according to the experience of the computer and the ...
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Ducted fan UAV hovering attitude control
Proceedings of 2011 International Conference on Electronic & Mechanical Engineering and Information Technology, 2011This paper focus on the modeling and control of a small ducted fan unmanned aerial vehicle (UAV). The mathematical model of the hovering flight UAV is established from aerodynamic analysis. Then, a control method for the hovering flight was obtained, which is based on the H ∞ control theory.
Xiao-Lu Ren, Changhong Wang, Guo-xing Yi
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Experimental framework for a Ducted-Fan Miniature Aerial Vehicle
2009 American Control Conference, 2009This paper focuses on the design and validation of a control framework for a Ducted-Fan Miniature Aerial Vehicle (MAV) realized by the University of Bologna in order to pursuit simple high level operations like surveillance, video capture, etc. After a description of the aircraft prototype and the nonlinear control law, two different control scenarios ...
GENTILI, LUCA +3 more
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Performance and Stability of Ducted-Fan Uninhabited Aerial Vehicle Model
Journal of Aircraft, 2001The nonlinear model of a novel ducted-fan uninhabited aerial vehicle is presented, where the aerodynamic coefficients are determined by numerical analysis of the flowfield about the airframe. The model is used to investigate performance and stability characteristics and to gain a sound physical understanding of dynamic behavior of this unconventional ...
G. AVANZINI G. +2 more
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