Rotorcraft aerodynamics are very complex because three-dimensional unsteady transonic viscous aerodynamic phenomena are involved. The ability to predict the flow around helicopter rotors is vital for the control of high-speed losses, vibration, and noise. The advent of tilt-rotor aircraft in the past few years further complicates rotor aerodynamics. Parallelization techniques for rotorcraft aerodynamics were studied. Two algorithmic changes are made for the efficient parallelization of the Navier-Stokes mode of TURNS. A new implicit operator, FM-Hybrid, based on the hybrid LU-SGS operator of Wissink and the DPLR implicit operator developed by Wright et al., has been implemented in TURNS. Both the hybrid LU-SGS and DPLR methods use the exact flux Jacobians and remove the spectral radius approach in the LU-SGS algorithm. The main reason for using exact forma of the Jacobians is to remove the overstabilizing effect of the spectral radius approximation for high CAR grids, which are needed for viscous computations. The operators are parallelized using message passing, and their efficiency is compared with DP-LUR and hybrid LU-SGS methods on an IBM SP2 supercomputer. Remarkable performance increase over the diagonal methods has been obtained with the implementation of these operators. The FM-Hybrid method seems to perform slightly better than DPLR in the three-dimensional, quasi-steady Navier-Stokes case. On the other hand, the DPLR method performs better than FM-Hybrid for two-dimensional test cases regardless of the maximum CAR of the grid. The authors have also tested these operators for the first time for unsteady three-dimensional calculations. They found that DPLR is not efficient for time-accurate calculations. However, FM-Hybrid performs better than the diagonal-based methods, and significant CPU time savings, for example, 72% vs hybrid LU-SGS and 84% vs DP-LUR, can be obtained.


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    Titel :

    Parallelization of rotorcraft aerodynamics Navier-Stokes codes


    Weitere Titelangaben:

    Parallelalgorithmen zur Lösung der Navier-Stokes-Gleichung zur Berechnung der Umströmung von Drehflügelflugzeugen


    Beteiligte:
    Ekici, K. (Autor:in) / Lyrintzis, A.S. (Autor:in)

    Erschienen in:

    AIAA Journal ; 40 , 5 ; 887-896


    Erscheinungsdatum :

    2002


    Format / Umfang :

    10 Seiten, 15 Bilder, 2 Tabellen, 33 Quellen




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch