Investigation of Helicopter Rotor-Blade-Tip-Vortex Alleviation Using a Slotted Tip

AIAA Journal ◽  
2004 ◽  
Vol 42 (3) ◽  
pp. 524-535 ◽  
Author(s):  
Yong Oun Han ◽  
J. Gordon Leishman
Keyword(s):  
Rotor Blade ◽  
Tip Vortex ◽  
Helicopter Rotor ◽  
Helicopter Rotor Blade ◽  
Blade Tip

A review of helicopter rotor blade tip shapes

2013 ◽  
Vol 56 ◽  
pp. 35-74 ◽  
Author(s):  
A. Brocklehurst ◽  
G.N. Barakos
Keyword(s):  
Rotor Blade ◽  
Helicopter Rotor ◽  
Helicopter Rotor Blade ◽  
Blade Tip

Autonomous camber morphing of a helicopter rotor blade with temperature change using integrated shape memory alloys

2020 ◽  
pp. 1045389X2095361
Author(s):  
Matthew DiPalma ◽  
Farhan Gandhi
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Temperature Change ◽  
Rotor Blade ◽  
Leading Edge ◽  
Lower Surface ◽  
Helicopter Rotor ◽  
Target Values ◽  
Helicopter Rotor Blade ◽  
Blade Tip

The present study proposes and explores a new autonomous morphing concept, where a 12–13° increase in camber is realized over a spanwise section of a helicopter rotor blade with increase in ambient temperature. The camber change is achieved through integration of Shape Memory Alloys (SMAs) on the lower surface of the blade, aft of the leading-edge spar. For a reference rotor of a utility-class helicopter generating 21,000 lbs thrust, a loss in lift of 2590 lb was observed due to operation in hot conditions. With the SMA camber morphing section extending from the blade root to 25%, 50%, and 75% span, the rotor recovered up to 11%, 43%, and 82% of the lift loss at high temperature (compared to a no-SMA blade). If the morphing section instead spans the outboard 25% of the blade (from 75% span to the blade tip), up to a 66% lift recovery is achieved due to the higher dynamic pressures over this region. While these results are achieved with existing SMA properties, idealized target values are also presented. For the SMA considered in the study, while a 40–115°F temperature change was required to achieve the full 12–13° design camber change, partial camber is achieved over a smaller temperature range. The paper identifies desired SMA properties that would produce a 12–13° camber change over an 80–100°F temperature change.

H ∞ Control of Smart Structure Helicopter Rotor Blade

1991 ◽  
Author(s):  
R. Kashani ◽  
S. Melkote ◽  
A. Sorgenfrei
Keyword(s):  
Rotor Blade ◽  
Active Vibration Control ◽  
Region Of Interest ◽  
Smart Structure ◽  
Helicopter Rotor ◽  
Appreciable Amount ◽  
Modelling Uncertainty ◽  
Helicopter Rotor Blade ◽  
Active Vibration ◽  
Bending Modes

Abstract Active vibration control of helicopter rotor blade is studied. For the purpose of illustration, we have considered only flap wise vibration of a hingeless rotor blade, and modelled it, using finite element method, by 20 beam elements. The first 12 bending modes of the system are considered in the model. A H∞ controller is designed for the plant formulated as above. The result of the numerical simulation of the closed-loop system shows that the control introduces an appreciable amount of damping in the frequency region of interest. The consideration of the modelling uncertainty in the synthesis of the controller resulted in a design which is robust stable in presence of formulated model uncertainty.

An Investigation of the Aerodynamic and Vibration Behavior of a Helicopter Rotor Blade

2020 ◽  
Author(s):  
Mohammad Khairul Habib Pulok ◽  
Uttam K. Chakravarty
Keyword(s):  
Rotor Blade ◽  
Fluid Structure Interaction ◽  
Interaction Model ◽  
Scale Model ◽  
Helicopter Rotor ◽  
Small Scale ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Aerodynamic Analysis ◽  
Helicopter Rotor Blade

Abstract Rotary-wing aircrafts are the best-suited option in many cases for its vertical take-off and landing capacity, especially in any congested area, where a fixed-wing aircraft cannot perform. Rotor aerodynamic loading is the major reason behind helicopter vibration, therefore, determining the aerodynamic loadings are important. Coupling among aerodynamics and structural dynamics is involved in rotor blade design where the unsteady aerodynamic analysis is also imperative. In this study, a Bo 105 helicopter rotor blade is considered for computational aerodynamic analysis. A fluid-structure interaction model of the rotor blade with surrounding air is considered where the finite element model of the blade is coupled with the computational fluid dynamics model of the surrounding air. Aerodynamic coefficients, velocity profiles, and pressure profiles are analyzed from the fluid-structure interaction model. The resonance frequencies and mode shapes are also obtained by the computational method. A small-scale model of the rotor blade is manufactured, and experimental analysis of similar contemplation is conducted for the validation of the numerical results. Wind tunnel and vibration testing arrangements are used for the experimental validation of the aerodynamic and vibration characteristics by the small-scale rotor blade. The computational results show that the aerodynamic properties of the rotor blade vary with the change of angle of attack and natural frequency changes with mode number.

Design optimization of helicopter rotor using kriging

2018 ◽  
Vol 90 (6) ◽  
pp. 937-945 ◽  
Author(s):  
Saijal Kizhakke Kodakkattu ◽  
Prabhakaran Nair ◽  
Joy M.L.
Keyword(s):  
Rotor Blade ◽  
Optimization Problem ◽  
Torsional Stiffness ◽  
Helicopter Rotor ◽  
Vibration Level ◽  
Content Type ◽  
Aeroelastic Analysis ◽  
Kriging Metamodel ◽  
Helicopter Rotor Blade ◽  
Trailing Edge Flaps

Purpose The purpose of this study is to obtain optimum locations, peak deflection and chord of the twin trailing-edge flaps and optimum torsional stiffness of the helicopter rotor blade to minimize the vibration in the rotor hub with minimum requirement of flap control power. Design/methodology/approach Kriging metamodel with three-level five variable orthogonal array-based data points is used to decouple the optimization problem and actual aeroelastic analysis. Findings Some very good design solutions are obtained using this model. The best design point in minimizing vibration gives about 81 per cent reduction in the hub vibration with a penalization of increased flap power requirement, at normal cruise speed of rotor-craft flight. Practical implications One of the major challenges in the helicopters is the high vibration level in comparison with fixed wing aircraft. The reduction in vibration level in the helicopter improves passenger and crew comfort and reduces maintenance cost. Originality/value This paper presents design optimization of the helicopter rotor blade combining five design variables, such as the locations of twin trailing-edge flaps, peak deflection and flap chord and torsional stiffness of the rotor. Also, this study uses kriging metamodel to decouple the complex aeroelastic analysis and optimization problem.

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