Download or read book An Overset Grid Navier Stokes Kirchhoff surface Method for Rotorcraft Aeroacoustic Predictions written by Earl P. N. Duque and published by . This book was released on 1996 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "This paper describes a new method for computing the flowfield and acoustic signature of arbitrary rotors in forward flight. The overall scheme uses a finite-difference Navier-Stokes solver to compute the aerodynamic flowfield near the rotor blades. The equations are solved on a system of overset grids that allow for prescribed cyclic and flapping blade motions and capture the interactions between the rotor blades and wake. The far-field noise is computed with a Kirchhoff integration over a surface that completely encloses the rotor blades. Flowfield data are interpolated onto this Kirchhoff surface using the same overset-grid techniques that are used for the flowfield solution. As a demonstration of the overall prediction scheme, computed results for far-field noise are compared with experimental data for both high-speed impulsive (HSI) and blade-vortex interaction (BVI) cases. The HSI case showed good agreement with experimental data while a preliminary attempt at the BVI case did not. The computations clearly show that temporal accuracy, spatial accuracy and grid resolution in the Navier-Stokes solver play key roles in the overall accuracy of the predicted noise. These findings will be addressed more closely in future BVI computations. Overall, the overset-grid CFD scheme provides a powerful new framework for the prediction of helicopter noise."
Download or read book New Computational Methods for the Prediction and Analysis of Helicopter Noise written by Roger C. Strawn and published by . This book was released on 1996 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "This paper describes several new methods to predict and analyze rotorcraft noise. These methods are: 1) a combined computational fluid dynamics and Kirchhoff scheme for far-field noise predictions, 2) parallel computer implementation of the Kirchhoff integrations, 3) audio and visual rendering of the computed acoustic predictions over large far-field regions, and 4) acoustic tracebacks to the Kirchhoff surface to pinpoint the sources of the rotor noise. The paper describes each method and presents sample results for three test cases. The first case consists of in-plane high-speed impulsive noise and the other two cases show idealized parallel and oblique blade-vortex interactions. The computed results show good agreement with available experimental data but convey much more information about the far-field noise propagation. When taken together, these new analysis methods exploit the power of new computer technologies and offer the potential to significantly improve our prediction and understanding of rotorcraft noise."
Download or read book Wind Energy for the Next Millennium written by E. L. Petersen and published by Earthscan. This book was released on 1999 with total page 1290 pages. Available in PDF, EPUB and Kindle. Book excerpt: First Published in 1999. Routledge is an imprint of Taylor & Francis, an informa company.
Download or read book The Kirchhoff Formulas for Moving Surfaces in Aeroacoustics The Subsonic and Supersonic Cases written by and published by . This book was released on 1996 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 1999 European Wind Energy Conference written by E.L. Petersen and published by Routledge. This book was released on 2014-01-02 with total page 1281 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 1999 European Wind Energy Conference and Exhibition was organized to review progress, and present and discuss the wind energy business, technology and science for the future. The Proceedings contain a selection of over 300 papers from the conference. They represent a significant update to the understanding of this increasingly important field of energy generation and cover a full range of topics.
Download or read book 2nd AIAA CEAS Aeroacoustics Conference written by and published by . This book was released on 1996 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Efficient Helicopter Aerodynamic and Aeroacoustic Predictions on Parallel Computers written by Andrew M. Wissink and published by . This book was released on 1996 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "This paper presents parallel implementations of two codes used in a combined CFD/Kirchhoff methodology to predict the aerodynamics and aeroacoustics properties of helicopters. The rotorcraft Navier-Stokes code, TURNS, computes the aerodynamic flowfield near the helicopter blades and the Kirchhoff acoustics code computes the noise in the far field, using the TURNS solution as input. The overall parallel strategy adds MPI message passing calls to the existing serial codes to allow for communication between processors. As a result, the total code modifications required for parallel execution are relatively small. The biggest bottleneck in running the TURNS code in parallel comes from the LU-SGS algorithm that solves the implicit system of equations. We use a new hybrid domain decomposition implementation of LU-SGS to obtain good parallel performance on the SP-2. TURNS demonstrates excellent parallel speedups for quasi-steady and unsteady three-dimensional calculations of a helicopter blade in forward flight. The execution rate attained by the code on 114 processors is six times faster than the same cases run on one processor of the Cray C-90. The parallel Kirchhoff code also shows excellent parallel speedups and fast execution rates. As a performance demonstration, unsteady acoustic pressures are computed at 1886 far-field observer locations for a sample acoustics problem. The calculation requires over two hundred hours of CPU time on one C-90 processor but takes only a few hours on 80 processors of the SP2. The resultant far-field acoustic field is analyzed with state-of-the-art audio and video rendering of the propagating acoustic signals."
Download or read book Journal of the American Helicopter Society written by American Helicopter Society and published by . This book was released on 1999 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ASME Wind Energy Symposium written by and published by . This book was released on 1999 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 34th Aerospace Sciences Meeting Exhibit written by and published by . This book was released on 1996 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parallel Computational Fluid Dynamics 99 written by D. Keyes and published by Elsevier. This book was released on 2000-10-18 with total page 477 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contributed presentations were given by over 50 researchers representing the state of parallel CFD art and architecture from Asia, Europe, and North America. Major developments at the 1999 meeting were: (1) the effective use of as many as 2048 processors in implicit computations in CFD, (2) the acceptance that parallelism is now the 'easy part' of large-scale CFD compared to the difficulty of getting good per-node performance on the latest fast-clocked commodity processors with cache-based memory systems, (3) favorable prospects for Lattice-Boltzmann computations in CFD (especially for problems that Eulerian and even Lagrangian techniques do not handle well, such as two-phase flows and flows with exceedingly multiple-connected demains with a lot of holes in them, but even for conventional flows already handled well with the continuum-based approaches of PDEs), and (4) the nascent integration of optimization and very large-scale CFD. Further details of Parallel CFD'99, as well as other conferences in this series, are available at http://www.parcfd.org
Download or read book Study on Optimized Upwind Schemesfor Computational Areoacoustics sic and Extension of a Fully Conservative Chimera to Finite Difference Schemes written by Rangfu Chen and published by . This book was released on 1998 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Collection of the 1999 ASME Wind Energy Symposium Technical Papers written by American Institute of Aeronautics and Astronautics and published by . This book was released on 1999 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume collects together the 1999 ASME Wind Energy Symposium technical papers.
Download or read book 40th AIAA Aerospace Sciences Meeting Exhibit written by and published by . This book was released on 2002 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Finding Guide to AIAA Meeting Papers written by American Institute of Aeronautics and Astronautics. Technical Information Service and published by . This book was released on 1996 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal of the Earth Simulator written by and published by . This book was released on 2004 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:
