Experimental investigation of the effects of different helicopter rotor tip geometries on aerodynamic performance and tip vortex characteristics

2018-09-05
Uluocak, Sinem
Hazaveh, Hooman Amiri
Perçin, Mustafa
Akpolat, M Tuğrul
Uzol, Oğuz
Show full item record
362
views
0
downloads
In this study, the effects of different tip geometries (rectangular, anhedral, swept-tapered and swept-tapered-anhedral) on the rotor hover performance and tip vortex characteristics are investigated experimentally. A scaled rotor model set-up, instrumented with thrust and torque sensors, is used for aerodynamic performance measurements in hover and a two-dimensional (2D) particle image velocimetry (PIV) is used to obtain the tip vortex characteristics such as vortex trajectory, maximum tangential velocity, and circulation. Although taper+swept and taper+swept+anhedral configurations have the best CT/CQ values at lower blade loadings, at higher blade loadings anhedral case has the best performance and an increase of 0.03 figure of merit compared to the baseline. It is observed that different tip shapes change the vortex trajectory, in addition, reduces maximum tangential velocity and circulation significantly. The PIV measurements which were performed at a high blade loading show that there is a correlation between the aerodynamic performance and the vortex strength.
Computerized tomography, Velocity measurement, Vortex flow, Wind tunnels
https://hdl.handle.net/11511/78260
44th European Rotorcraft Forum 2018, ERF 2018; (18 September 2018 through 21 September 2018)
Department of Aerospace Engineering, Conference / Seminar

Suggestions

Experimental investigation of the effects of tip-injection on the aerodynamic loads and wake characteristics of a model horizontal axis wind turbine rotor
Abdulrahim, Anas; Uzol, Oğuz; Department of Aerospace Engineering (2014)
In this study, tip injection is implemented on a model Horizontal Axis Wind Turbine (HAWT) rotor to investigate the power and thrust coefficient variations as well as the wake characteristics. The model wind turbine has a 0.95 m diameter 3-bladed rotor with non-linearly twisted and tapered blades that has NREL S826 profile. The nacelle, hub and the blades are specifically designed to allow pressurized air to pass through and get injected from the tips while the rotor is rotating. The experiments are perform...
Experimental Investigation of the Effects of Winglets on the Tip Vortex Behavior of a Model Horizontal Axis Wind Turbine Using Particle Image Velocimetry
Ostovan, Yasar; Akpolat, M. Tugrul; Uzol, Oğuz (2019-02-01)
This study presents an experimental investigation on the effects of winglets on the near wake flow around the tip region and on the tip vortex characteristics downstream of a 0.94 m diameter three-bladed horizontal axis wind turbine (HAWT) rotor. Phase-locked 2D particle image velocimetry (PIV) measurements are performed with and without winglets covering 120 deg of azimuthal progression of the rotor. The impact of using winglets on the flow field near the wake boundary as well as on the tip vortex characte...
Experimental investigation of tip anhedral effects on the aerodynamics of a model helicopter rotor in hover
Uluocak, Sinem; Perçin, Mustafa; Uzol, Oğuz (2021-06-01)
This study experimentally investigates the effects of tip anhedral on the rotor aerodynamic performance and the tip vortex characteristics in hovering flight. A five-bladed scaled helicopter rotor with blades that have either rectangular (baseline) or anhedral tip geometries was used as the experimental model. Thrust and torque measurements were performed at the tip Mach numbers (Mtip) of 0.3 and 0.4 at five different pitch angles. In addition, flow field measurements via phase-locked particle image velocim...
Experimental investigation of the helicopter blade tip shape effects on aerodynamic performance and tip vortex characteristics
Uluocak, Sinem; Perçin, Mustafa; Uzol, Oğuz; Department of Aerospace Engineering (2019)
This study experimentally investigates the effects of different rotor blade tip shapes on the rotor aerodynamic performance and the tip vortex characteristics in hovering flight. Force, torque and flow field measurements were performed on a 1.3 m diameter 5-bladed model rotor for four different blades: rectangular (RECT), anhedral (ANHD), tapered-swept (TAPER) and tapered-swept-anhedral (TSA). Thrust and torque measurements show that all tip modifications have a positive effect on the aerodynamic performance wh...
Experimental investigation of waveform tip injection on the characteristics of the tip vortex
Ostovan, Yashar; Uzol, Oğuz; Department of Aerospace Engineering (2011)
This study investigates the effect of chordwisely modulated tip injection on the flow and turbulence characteristics of the tip vortex through experimental measurements downstream of a rectangular half-wing that has an aspect ratio of three. This injection technique involves spanwise jets at the tip that are issued from a series of holes along the chord line normal to the freestream flow direction. The injection mass flow rate from each hole is individually controlled using computer driven solenoid valves a...
Citation Formats
S. Uluocak, H. A. Hazaveh, M. Perçin, M. T. Akpolat, and O. Uzol, “Experimental investigation of the effects of different helicopter rotor tip geometries on aerodynamic performance and tip vortex characteristics,” presented at the 44th European Rotorcraft Forum 2018, ERF 2018; (18 September 2018 through 21 September 2018), Delft, Netherlands, 2018, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/78260.
METU IIS - Integrated Information Service open@metu.edu.tr