Comprehensive multibody dynamics analysis for rotor aeromechanics predictions in descending flight

2012 ◽  
Vol 116 (1177) ◽  
pp. 229-249 ◽  
Author(s):  
J.-S. Park ◽  
S. N. Jung
Keyword(s):  
Test Data ◽  
Wind Tunnel Test ◽  
Flight Test ◽  
Helicopter Rotor ◽  
Helicopter Rotors ◽  
Blade Vortex Interaction ◽  
Blade Tip ◽  
Higher Harmonic ◽  
Reasonable Prediction ◽  
Hart Ii

AbstractThis paper studies the rotor aeromechanics in descending flight using a nonlinear flexible multibody dynamic analysis code, DYMORE. A freewake model is included in DYMORE to improve the rotor wake modelling. The wind-tunnel test data of the Higher-harmonic Aeroacoustics Rotor Test (HART) II rotor, with and without higher harmonic pitch control (HHC), and the flight test data of the full-scale utility helicopter rotor in descent are used for the aeromechanics correlation at an advance ratio of 0·15. The blade-vortex interaction (BVI) airloads are reasonably predicted for both the HART II and utility helicopter rotors, although some BVI peaks are missed on the advancing sides for both the rotors. The flap deflections and elastic torsion deformations at the blade tip are fairly correlated against the measured data of the HART II rotor. The correlation of blade structural moments for both HART II and utility helicopter rotors are not as good as the lift predictions; however, a reasonable prediction is obtained for the utility helicopter rotor.

Prediction of Blade-Vortex Interaction Airloads With Higher-Harmonic Pitch Controls Using the 2GCHAS Comprehensive Code

2001 ◽  
Vol 123 (4) ◽  
pp. 469-474 ◽  
Author(s):  
Joon W. Lim ◽  
Chee Tung ◽  
Yung H. Yu
Keyword(s):  
Tip Vortex ◽  
Vortex Interaction ◽  
Main Rotor ◽  
Scaled Model ◽  
Harmonic Control ◽  
Blade Vortex Interaction ◽  
Higher Harmonic Control ◽  
Blade Tip ◽  
Higher Harmonic ◽  
Analysis System

Analytically predicted results of blade-vortex interaction (BVI) airloads, using the second- generation comprehensive helicopter analysis system (2GCHAS), are presented with the experimental results obtained from the higher-harmonic-control aeroacoustic rotor test (HART) program using a 40-percent, Mach-scaled model of the hingeless BO-105 main rotor. Correlations include airloads, blade tip deflections, and tip vortex geometry. The effects on blade airload predictions are studied with higher-harmonic pitch controls (HHC). It was concluded that the blade torsional deflection and the wake system play a very important role in predicting BVI airloads.

scholarly journals Computational fluid dynamics trimming of helicopter rotor in forward flight

2020 ◽  
Vol 12 (5) ◽  
pp. 168781402092525 ◽  
Author(s):  
Chenglong Zhou ◽  
Ming Chen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Test Data ◽  
Pitch Angle ◽  
Flight Test ◽  
Helicopter Rotor ◽  
Main Rotor ◽  
Forward Flight ◽  
Thrust Coefficient ◽  
Moment Coefficient

A computational fluid dynamics (CFD) trimming method based on wind tunnel and flight test data is proposed. Aerodynamic coefficients obtained for a helicopter rotor using this method were compared with both experimental data from a test report and CFD results based on the control parameters that were reported in the same document. The method applies small disturbances to the collective pitch angle, the lateral cyclic pitch angle and the longitudinal cyclic pitch angle of the helicopter’s main rotor during forward flight to analyze the effects of each disturbance on the thrust coefficient, the pitching moment coefficient and the rolling moment coefficient of the rotor. Then, by solving a system of linear equations, the collective pitch angle, the lateral cyclic pitch angle and the longitudinal cyclic pitch angle of the main rotor in the CFD trim state are obtained. The AH-1G rotor is used in this paper. NASA has conducted a comprehensive flight test program on this model and has published detailed test reports. Using this method, the pitch moment and the roll moment can be corrected to almost zero and the calculated thrust coefficient is more consistent with the test data when compared with results from direct CFD simulations.

scholarly journals Impact of Higher Freeze Point Fuels on Naval Aircraft Operations

1986 ◽  
Author(s):  
R. A. Kamin ◽  
P. M. McConnell
Keyword(s):  
Test Data ◽  
Three Dimensional ◽  
Wind Tunnel Test ◽  
Flight Test ◽  
Computer Code ◽  
Scale Test ◽  
Process Studies ◽  
Freeze Point ◽  
Tank Geometry ◽  
The Impact

Refinery process studies have indicated that the relaxation of the JP-5 freeze point specification is a viable means of increasing jet fuel availability. The Naval Air Propulsion Center is investigating the impact of higher freeze point fuels on naval aircraft operations. Six fuels, with freeze points ranging from −55°F to +10°F, were tested in two instrumented external fuel tanks. Thirty hours of flight test and one hundred hours of wind tunnel test data have been accumulated. This information is being used in conjunction with laboratory and bench scale test data to support the development of a three dimensional computer code. This code will predict fuel cool down and hold-up (unpumpable frozen fuel) for any fuel tank geometry during a mission. Initial results indicate that the current JP-5 freeze point specification of −51°F is conservative and could be safely relaxed.

scholarly journals Design and Performance Evaluation of Propeller for Solar-Powered High-Altitude Long-Endurance Unmanned Aerial Vehicle

2018 ◽  
Vol 2018 ◽  
pp. 1-23 ◽  
Author(s):  
Donghun Park ◽  
Yunggyo Lee ◽  
Taehwan Cho ◽  
Cheolwan Kim
Keyword(s):  
Wind Tunnel ◽  
High Altitude ◽  
Test Data ◽  
Design Method ◽  
Wind Tunnel Test ◽  
Flight Test ◽  
Cfd Analysis ◽  
Aerial Vehicle ◽  
Solar Powered ◽  
Long Endurance

Design, wind tunnel test, computational fluid dynamics (CFD) analysis, and flight test data analysis are conducted for the propeller of EAV-3, which is a solar-powered high-altitude long-endurance unmanned aerial vehicle developed by Korea Aerospace Research Institute. The blade element momentum theory, in conjunction with minimum induced loss, is used as a basic design method. Airfoil data are obtained from CFD analysis, which takes into account the low Reynolds number effect. The response surface is evaluated for design variables by using design of experiment and kriging metamodel. The optimization is based on desirability function. A wind tunnel test is conducted on the designed propeller. Numerical analyses are performed by using a commercial CFD code, and results are compared with those obtained from the design code and wind tunnel test data. Flight test data are analyzed based on several approximations and assumptions. The propeller performance is in good agreement with the numerical and measurement data in terms of tendency and behavior. The comparison of data confirms that the design method, wind tunnel test, and CFD analysis used in this study are practically useful and valid for the development of a high-altitude propeller.

Stall Buffet Modeling using Swept Wing Flight Test Data

2021 ◽  
Author(s):  
Sven Marschalk ◽  
Peter C. Luteijn ◽  
Dirk van Os ◽  
Daan M. Pool ◽  
Coen C. de Visser
Keyword(s):  
Test Data ◽  
Flight Test ◽  
Swept Wing
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