Show/Hide Menu
Hide/Show Apps
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Open Access Guideline
Open Access Guideline
Postgraduate Thesis Guideline
Postgraduate Thesis Guideline
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Guides
Guides
Thesis submission
Thesis submission
MS without thesis term project submission
MS without thesis term project submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Supporting Information
Supporting Information
General Information
General Information
Copyright, Embargo and License
Copyright, Embargo and License
Contact us
Contact us
Experimental investigation of the helicopter blade tip shape effects on aerodynamic performance and tip vortex characteristics
Download
index.pdf
Date
2019
Author
Uluocak, Sinem
Metadata
Show full item record
Item Usage Stats
472
views
257
downloads
Cite This
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 when compared to the RECT tip configuration especially at low blade loadings. Overall, the ANHD tip configuration gives the best aerodynamic performance at high blade loadings. It reaches a maximum figure of merit (FOM) value of 0.67 and provides a FOM improvement of approximately 0.03 compared to the RECT blade at the tip Mach number (Mtip) of 0.3. Phase-locked particle image velocimetry measurements were conducted at 6◦ intervals between 0◦ -72◦ phase/wake ages at the selected pitch angle of 16◦ and Mtip = 0.4. It is observed that tip modifications change the tip vortex trajectory by increasing radial convection speed and decreasing axial convection speed. ANHD reduces the maximum vortex tangential velocity up to 20%; the TAPER and the TSA reduces it up to 30%. The minimum tip-vortex circulation level is achieved in the case of the ANHD blade, which is in agreement with the highest FOM obtained with this blade.
Subject Keywords
Blades.
,
Helicopters.
,
Vortex-motion.
,
Aerodynamics.
,
Rotors
URI
http://etd.lib.metu.edu.tr/upload/12623050/index.pdf
https://hdl.handle.net/11511/27972
Collections
Graduate School of Natural and Applied Sciences, Thesis
Suggestions
OpenMETU
Core
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 effects of different helicopter rotor tip geometries on aerodynamic performance and tip vortex characteristics
Uluocak, Sinem; Hazaveh, Hooman Amiri; Perçin, Mustafa; Akpolat, M Tuğrul; Uzol, Oğuz (Netherlands Association of Aeronautical Engineers; 2018-09-05)
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,...
Experimental analysis of flow structure on moderate sweep delta wing
Öztürk, İlhan; Yavuz, Mehmet Metin; Department of Mechanical Engineering (2014)
Experimental investigation of flow over a 45° moderate swept delta wing is performed using laser illuminated smoke visualization, surface pressure measurements, and Laser Doppler Anemometry (LDA) techniques in low-speed wind tunnel. The formation of leading-edge vortices and their breakdown, and three-dimensional separation from the surface of the wing are studied at broad range of attack angles and Reynolds numbers. Smoke visualizations are performed at three different cross flow planes along with vortex a...
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 Aerodynamics of Flapping-Wing Micro-Air-Vehicle by Force and Flow-Field Measurements
Deng, Shuanghou; Perçin, Mustafa; van Oudheusden, Bas (2016-02-01)
This study explores the aerodynamic characteristics of a flapping-wing micro aerial vehicle (MAV) in hovering configuration by means of force and flowfield measurements. The effects of flapping frequency and wing geometry on force generation were examined using a miniature six-component force sensor. Additional high-speed imaging allowed identification of the notable different deformation characteristics of the flexible wings under vacuum condition in comparison to their behavior in air, illustrating the re...
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
S. Uluocak, “Experimental investigation of the helicopter blade tip shape effects on aerodynamic performance and tip vortex characteristics,” M.S. - Master of Science, Middle East Technical University, 2019.