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Calculation of Multibladed Rotors in High-Speed Forward Flight with Weak Fluid-Structure-Coupling

Pahlke, K. and van der Wall, Berend G. (2001) Calculation of Multibladed Rotors in High-Speed Forward Flight with Weak Fluid-Structure-Coupling. In: 27th European Rotorcraft Forum Proceedings, 27.1-27.11. 27th European Rotorcraft Forum, Moscow (Russia), 11-14 September 2001.

Full text not available from this repository.

Abstract

A weak coupling procedure for coupling the rotor simulation code S4 and the Euler/Navier-Stokes solver FLOWer was presented. The method allows to produce trimmed CFD solutions for rotors in high speed forward flight accounting for elastic blade deformations and viscous effects. The weak coupling procedure was applied to high-speed forward flight test cases of the 7A and the 7AD rotor. Isolated blade computations were carried out for both rotors while a chimera computation around the whole 4-bladed rotor was carried out only for the 7A rotor. The predicted pitching moment computed with the assumption of inviscid flow (Euler) showed large differences compared to the experimental data. Between 0° and 90° azimuth the Euler pitching moment even had the wrong sign. A clear improvement of the solution with respect to the existing experimental data because of the weak coupling was proven. The well known negative peak in the normal forces distribution close to the blade tip around 90°-120° for elastic blades in high speed forward flight was well reproduced with the coupled Navier-Stokes computation although the computational results show a phase shift of about 10-15° azimuth. While the predicted elastic torsion for the 7A test case showed a considerable content of a 5/rev motion this was not the case for the 7AD rotor. The reason for this unexpected difference has to be clarified. The chimera technique provided more accurate results at the cost of an increase of computational effort by more than one order of magnitude. Although the method was based on isolated blade computations it was able to predict the performance differences between the 7A and the /AD rotor in high-speed forward flight fairly well while the absolute power was overpredicted for both rotors by about 10%.

Document Type:Conference or Workshop Item (Paper)
Additional Information: LIDO-Berichtsjahr=2001,
Title:Calculation of Multibladed Rotors in High-Speed Forward Flight with Weak Fluid-Structure-Coupling
Authors:
AuthorsInstitution or Email of Authors
Pahlke, K.UNSPECIFIED
van der Wall, Berend G.Institut für Flugsystemtechnik
Date:2001
Journal or Publication Title:27th European Rotorcraft Forum Proceedings
Page Range:27.1-27.11
Status:Published
Keywords:RANS, chimera, moving grids, deforming grids, elastic blades, multibladed rotors, forward flight, unsteady flows, fluid-structure coupling
Event Title:27th European Rotorcraft Forum, Moscow (Russia), 11-14 September 2001
Organizer:KAMOV Helicopters, Russian and Soviet Military Aircraft, Moscow, Russia
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Aeronautics
HGF - Program Themes:Rotorcraft
DLR - Research area:Aeronautics
DLR - Program:L RR - Rotorcraft Research
DLR - Research theme (Project):L - The Virtual Aerodynamic Rotorcraft
Location: Köln-Porz , Braunschweig , Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology
Institute of Flight Systems
Deposited By: elib DLR-Beauftragter
Deposited On:31 Jan 2006
Last Modified:14 Jan 2010 18:49

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