Download or read book The Sound of Propellers written by Clive King and published by . This book was released on 1986 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Radiation of Sound from a Propeller at Angle of Attack written by Ramani Mani and published by . This book was released on 1990 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Marine Propellers and Propulsion written by John Carlton and published by Butterworth-Heinemann. This book was released on 2012-10-30 with total page 539 pages. Available in PDF, EPUB and Kindle. Book excerpt: The early development of the screw propeller. Propeller geometry. The propeller environment. The ship wake field, propeller performance characteristics.
Download or read book Sound from Dual rotating and Multiple Single rotating Propellers written by Harvey H. Hubbard and published by . This book was released on 1948 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sound measurements for static conditions are presented for multiple propellers and the results are compared with a theoretical analysis of the problem. The sound from a four-blade dual-rotating propeller was found to fluctuate approximately between that from a two-blade and four-blade single-rotating propeller when the propellers are absorbing the same power at the same tip speed; the amount of fluctuation was found to depend on the angle of overlap with respect to the observer.
Download or read book Sources Control and Effects of Noise from Aircraft Propellers and Rotors written by John S. Mixson and published by . This book was released on 1981 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Marine Propellers and Propulsion written by John Carlton and published by Elsevier. This book was released on 2011-04-01 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although the propeller lies submerged out of sight, it is a complex component in both the hydrodynamic and structural sense. This book fulfils the need for a comprehensive and cutting edge volume that brings together a great range of knowledge on propulsion technology, a multi-disciplinary and international subject. The book comprises three main sections covering hydrodynamics; materials and mechanical considerations; and design, operation and performance. The discussion relates theory to practical problems of design, analysis and operational economy, and is supported by extensive design information, operational detail and tabulated data. Fully updated and revised to cover the latest advances in the field, the new edition now also includes four new chapters on azimuthing and podded propulsors, propeller-rudder interaction, high-speed propellers, and propeller-ice interaction. · The most complete book available on marine propellers, fully updated and revised, with four new chapters on azimuthing and podded propulsors, propeller-rudder interaction, high-speed propellers, and propeller-ice interaction· A valuable reference for marine engineers and naval architects gathering together the subject of propulsion technology, in both theory and practice, over the last forty years · Written by a leading expert on propeller technology, essential for students of propulsion and hydrodynamics, complete with online worked examples
Download or read book Noise of the SR 6 Propeller Model at 2 Deg and 4 Deg Angles of Attack written by and published by . This book was released on 1983 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Noise and Performance of Propellers for Light Aircraft written by Massachusetts Institute of Technology. Gas Turbine & Plasma Dynamics Laboratory and published by . This book was released on 1980 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Propeller Noise at Low Tip Speeds written by David Brown and published by . This book was released on 1971 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study comprises an analytical and experimental investigation of the vortex noise generated by low-tip speed propellers. Initally, the treatment of the subject is focussed on an examination of the origins of broadband noise and the methods by which these can be analytically represented. Subsequent noise measurements on simple-design propellers indicate how the typical spectra in the Strouhal frequency range are significantly influenced by an extensive range of high order harmonics of the blade passage frequency, and a treatment of this harmonic content is included in this study report. The broadband and harmonic components of noise data, obtained from propellers with blade number and blade angle variations, have been analyzed in detail and noise prediction methods have been derived for each. It is postulated that the noise source mechanisms may be associated with unstable laminar flow separation (or transition) at the blade surfaces. The report also includes a set of graphical procedures by which both harmonic and random spectral details of the radiated noise can be calculated by tip Mach numbers in the range 0.2 to 0.6. (Author).
Download or read book Sound Measurements for Five Shrouded Propellers at Static Conditions written by Harvey H. Hubbard and published by . This book was released on 1950 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sound-pressure measurements are reported for five shrouded propellers and are compared with those for an unshrouded propeller operating at approximately the same rotational speed and power. The maximum total sound pressure produced by a two-blade shrouded propeller is found to vary approximately from one-half to twice as much as that for an unshrouded two-blade propeller, depending on whether the flow at the shroud surface is unseparated or separated, respectively. Shroud chord is found not to be critical except insofar as the areodynamic considerations are affected. In general, if the shroud-propeller unit satisfies aerodynamic requirements, good sound characteristics will also be obtained.
Download or read book Aeroacoustics of Flight Vehicles written by Harvey H. Hubbard and published by . This book was released on 1991 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Noise of the SR 3 Propeller Model at 2 Deg and 4 Deg Angle of Attack written by and published by . This book was released on 1981 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analytic Studies of Sound Pressures Inside the Duct of Ducted Propellers written by Joseph A. Drischler and published by . This book was released on 1971 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pressure distribution analysis of sound inside duct of ducted propellers.
Download or read book A Shock Wave Approach to the Noise of Supersonic Propellers written by and published by . This book was released on 1981 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation Noise from Electric Low Tip Speed Aircraft Propellers written by Bolor Zolbayar and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on propeller noise considerations that would be appropriate for a6-9 passenger low-tip-speed, electric propeller-driven aircraft. A baseline aircraft andpropeller are used for reference, but all the propellers evaluated in this work havebeen designed for appropriate tip speeds considered. Electric motors are lighter thanconventional combustion engines. They also can operate at low-tip-speed more effectively than conventional internal combustion engines. These characteristics allow aircraft to have multiple low-tip-speed propellers, which can result in a reduction in propeller noise.In this research, the noise of isolated propellers designed for low Mtip=0.3 and 0.4 wasinvestigated and compared with noise of a baseline propeller designed for Mtip=0.7 forthe same thrust and forward aircraft speed. The design and analysis code CROTOR is used to design all the propellers in this work. The lower tip speed reduces the noise considerably, but the individual noise sources tend to not scale with tip Mach number in the same way. With steady axisymmetric inflow at the level flight condition, the maximum propeller noise is always found in the propeller plane. To study the relationship between propeller noise and tip speed, isolated 3 and 6-bladed propellers are designed for various tip speeds. (Mtip = 0.3, 0.4, 0.5, 0.6, and 0.7). For steady level flight cases, the noise in the propeller plane is found to be the highest and is found to have a linear relationship with blade tip speed.Unsteady loading is implemented as an approximation to the loading propellerexperiences when it operates at an angle of attack. The effect of unsteady loading isshown to change the directivity of the noise distribution substantially in the plane ofthe propeller and to impact the ultimate noise reduction achievable through tip speedreduction, especially for low-tip-speed designs. In particular, along with the propeller axisof rotation, the noise levels do not change significantly with tip speed, while in the planeof the propeller, the noise reduction with reduced tip Mach number is promising. However, with higher angles of attack, the noise below the propeller increases substantially, and its directivity rotates approximately by the angle of attack .Increasing the number of blades can result in significant noise reduction in theplane of rotation (up to 25 dB), but practical limits on the number of blades shouldbe investigated. Distributed electric propulsion system makes it feasible to use several smaller propellers. So, configurations with 1, 2, 4, and 6-propellers designed in CROTORcode were considered. In the plane of rotation, the noise directivity becomes increasinglycomplex with an increasing number of propellers and the noise directivity can be shapedinto "loud" and "quiet" directions.These results are aimed to give some direction that could be helpful to design engineersand to demonstrate how current design and analysis tools can be used in a fast and simple manner to obtain propeller noise predictions.
Download or read book Potential Subjective Effectiveness of Active Interior Noise Control in Propeller Airplanes written by Clemans A. Powell and published by . This book was released on 2000 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Active noise control technology offers the potential for weight-efficient interior noise reduction, particularly for propeller aircraft. However, there is little information on how passengers respond to this type of interior noise control. This paper presents results of two experiments that use sound quality engineering practices to determine the subjective effectiveness of hypothetical active noise control (ANC) systems in a range of propeller aircraft. The two experiments differed by the type of judgments made by the subjects: pair comparisons based on preference in the first and numerical category scaling of noisiness in the second. Although the results of the two experiments were in general agreement that the hypothetical active control measures improved the interior noise environments, the pair comparison method appears to be more sensitive to subtle changes in the characteristics of the sounds which are related to passenger preference. The reductions in subjective response due to the ANC conditions were predicted with reasonable accuracy by reductions in measured loudness level. Inclusion of corrections for the sound quality characteristics of tonality and fluctuation strength in multiple regression models improved the prediction of the ANC effects.
Download or read book A Parametric Investigation of an Existing Supersonic Relative Tip Speed Propeller Noise Model written by James H. Dittmar and published by . This book was released on 1977 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
