Turbulence and helicopter response to turbulence require blade-fixed sampling. They are stationary at time intervals of one rotor revolution, but they vary cyclically within each revolution (cyclostationary). State-of-the-art methods of turbulence simulation and response prediction are sequential and take excessive execution time. They are not practical for comprehensive helicopter-turbulence modeling that involves high-order helicopter models in two- and three-dimensional turbulence. Accordingly, parallel methods of turbulence simulation and response prediction are developed; they are applied to simulate one-, two- and three-dimensional turbulence and to predict flapping responses of isolated blades and rotors. Classical turbulence and quasisteady airfoil theories are used, dynamic wake is included by a three-dimensional finite-state wake model, and both rigid and elastic-blade flapping are considered. The second-order statistics of turbulence and response from the sequential and parallel methods are nearly identical. With increasing comprehensiveness of helicopter-turbulence modeling, the sequential simulation and response-prediction times increase dramatically; for example, the response-prediction time increases between quadratically and cubically with the model order. By comparison, the corresponding parallel execution times are far lower and, more significantly, remain nearly constant. Thus, the parallel methods offer promise for detailed handling-qualities and dynamics evaluations.
Parallel methods for turbulence simulation and helicopter-response prediction
Parallelmethoden zur turbulenten Strömungssimulation und Vorhersage des Flugverhaltens von Helikoptern
Journal of the American Helicopter Society ; 41 , 3 ; 219-231
1996
13 Seiten, 12 Bilder, 24 Quellen
Article (Journal)
English
Hubschrauber , Rotor (Drehflügel) , Aerodynamik , turbulente Strömung , Simulationsmodell , Flugverhalten , Vorhersage , Stichprobe , Flatterschwingung , dreidimensionale Strömung , Tragflügeltheorie , statistische Analyse , elastische Eigenschaft , Rechenzeit , Korrelation , Frequenzspektrum , Bessel-Funktion
Parallel methods for turbulence simulation and helicopter-response prediction
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