Design, Manufacturing, and Testing of a New Concept for a Morphing Leading Edge using a Subsonic Blow Down Wind Tunnel

This paper presents the design and wind tunnel test results of a wing including a morphing leading edge for a medium unmanned aerial vehicle with a maximum wingspan of 5 m. The design of the morphing leading edge system is part of research on the design of a morphing camber system. The concept presented here has the advantage of being simple to manufacture (wooden construction) and light for the structure of the wing (compliance mechanism). The morphing leading edge prototype demonstrates the possibility of modifying the stall angle of the wing. In addition, the modification of the stall angle is performed without affecting the slope of the lift coefficient. This prototype is designed to validate the functionality of the deformation method applied to the leading edge of the wing. The mechanism can be further optimized in terms of shape and material to obtain a greater deformation of the leading edge, and, thus, to have a higher impact on the increase of the stall angle than the first prototype of the morphing leading edge presented in this paper.

Download Full-text

Design and Validation of a New Morphing Camber System by Testing in the Price—Païdoussis Subsonic Wind Tunnel

Aerospace ◽

10.3390/aerospace7030023 ◽

2020 ◽

Vol 7 (3) ◽

pp. 23 ◽

Cited By ~ 1

Author(s):

David Communier ◽

Ruxandra Mihaela Botez ◽

Tony Wong

Keyword(s):

Wind Tunnel ◽

Unmanned Aerial Vehicle ◽

Lift Coefficient ◽

Angle Of Attack ◽

Leading Edge ◽

Trailing Edge ◽

Subsonic Wind Tunnel ◽

Aerial Vehicle ◽

Stall Angle

This paper presents the design and wind tunnel testing of a morphing camber system and an estimation of performances on an unmanned aerial vehicle. The morphing camber system is a combination of two subsystems: the morphing trailing edge and the morphing leading edge. Results of the present study show that the aerodynamics effects of the two subsystems are combined, without interfering with each other on the wing. The morphing camber system acts only on the lift coefficient at a 0° angle of attack when morphing the trailing edge, and only on the stall angle when morphing the leading edge. The behavior of the aerodynamics performances from the MTE and the MLE should allow individual control of the morphing camber trailing and leading edges. The estimation of the performances of the morphing camber on an unmanned aerial vehicle indicates that the morphing of the camber allows a drag reduction. This result is due to the smaller angle of attack needed for an unmanned aerial vehicle equipped with the morphing camber system than an unmanned aerial vehicle equipped with classical aileron. In the case study, the morphing camber system was found to allow a reduction of the drag when the lift coefficient was higher than 0.48.

Download Full-text

Wind Tunnel Test of the S814 Thick Root Airfoil

Journal of Solar Energy Engineering ◽

10.1115/1.2871781 ◽

1996 ◽

Vol 118 (4) ◽

pp. 217-221 ◽

Cited By ~ 10

Author(s):

D. M. Somers ◽

J. L. Tangler

Keyword(s):

Wind Tunnel ◽

Lift Coefficient ◽

Wind Tunnel Test ◽

Leading Edge ◽

Reynolds Numbers ◽

Rotor Blades ◽

Roughness Effects ◽

Root Region ◽

University Of Technology ◽

Thick Airfoil

The objective of this wind-tunnel test was to verify the predictions of the Eppler Airfoil Design and Analysis Code for a very thick airfoil having a high maximum lift coefficient designed to be largely insensitive to leading-edge roughness effects. The 24 percent thick S814 airfoil was designed with these characteristics to accommodate aerodynamic and structural considerations for the root region of a wind-turbine blade. In addition, the airfoil’s maximum lift-to-drag ratio was designed to occur at a high lift coefficient. To accomplish the objective, a two-dimensional wind tunnel test of the S814 thick root airfoil was conducted in January 1994 in the low-turbulence wind tunnel of the Delft University of Technology Low Speed Laboratory, The Netherlands. Data were obtained with transition free and transition fixed for Reynolds numbers of 0.7, 1.0, 1.5, 2.0, and 3.0 × 106. For the design Reynolds number of 1.5 × 106, the maximum lift coefficient with transition free is 1.32, which satisfies the design specification. However, this value is significantly lower than the predicted maximum lift coefficient of almost 1.6. With transition fixed at the leading edge, the maximum lift coefficient is 1.22. The small difference in maximum lift coefficient between the transition-free and transition-fixed conditions demonstrates the airfoil’s minimal sensitivity to roughness effects. The S814 root airfoil was designed to complement existing NREL low maximum-lift-coefficient tip-region airfoils for rotor blades 10 to 15 meters in length.

Download Full-text

Summary of the Delft University Wind Turbine Dedicated Airfoils

Journal of Solar Energy Engineering ◽

10.1115/1.1626129 ◽

2003 ◽

Vol 125 (4) ◽

pp. 488-496 ◽

Cited By ~ 204

Author(s):

W. A. Timmer ◽

R. P. J. O. M. van Rooij

Keyword(s):

Wind Turbine ◽

Lift Coefficient ◽

Wind Tunnel Test ◽

Leading Edge ◽

Vortex Generators ◽

Test Results ◽

Relative Thickness ◽

University Of Technology ◽

Measured Effect ◽

Edge Separation

This paper gives an overview of the design and wind tunnel test results of the wind turbine dedicated airfoils developed by Delft University of Technology (DUT). The DU-airfoils range in maximum relative thickness from 15% to 40% chord. The first designs were made with the XFOIL code. The computer program RFOIL, which is a modified version of XFOIL featuring an improved prediction around the maximum lift coefficient and the capability of predicting the effect of rotation on airfoil characteristics, has been used to design the airfoils since 1995. The measured effect of Gurney flaps, trailing edge wedges, vortex generators (vg) and trip wires on the airfoil characteristics of various DU-airfoils is presented. Furthermore, a relation between the thickness of the airfoil leading edge and the angle-of-attack for leading edge separation is given.

Download Full-text

Wind Tunnel Test of Effect of Sound-Absorbing Material on Lift of Two-Element Airfoil

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.830.17 ◽

2013 ◽

Vol 830 ◽

pp. 17-23

Author(s):

Yong Wei Gao ◽

Qi Liang Zhu ◽

Long Wang

Keyword(s):

Wind Tunnel ◽

High Frequency ◽

Lift Coefficient ◽

Wind Tunnel Test ◽

Low Frequency ◽

Leading Edge ◽

Aerodynamic Characteristics ◽

Fluctuating Pressure ◽

Flow Parameters ◽

Absorbing Material

The flow parameters of fluctuating pressure and fluctuating velocity in the gap can be changed by the porous absorption material on the leading edge of upper surface of the flap of multi-element airfoil (GAW-1),and the aerodynamic characteristics is also altered. Experiment was conducted in the NF-3 wind tunnel. It turns out that porous absorption material has a significant effect on fluctuating velocity (i.e. turbulent kinetic energy), and the lift coefficient drops when fluctuating velocity increases ; but the influence on RMS of fluctuating pressure on upper surface is not obvious; the average speed in gap is reduced. The PSD of fluctuating pressure and fluctuating velocity show that low-frequency signal has a more obvious influence on lift of multi-element airfoils than high-frequency.

Download Full-text

Summary of the Delft University Wind Turbine Dedicated Airfoils

ASME 2003 Wind Energy Symposium ◽

10.1115/wind2003-352 ◽

2003 ◽

Cited By ~ 33

Author(s):

W. A. Timmer ◽

R. P. J. O. M. van Rooij

Keyword(s):

Wind Turbine ◽

Lift Coefficient ◽

Wind Tunnel Test ◽

Leading Edge ◽

Vortex Generators ◽

Test Results ◽

Relative Thickness ◽

University Of Technology ◽

Measured Effect ◽

Edge Separation

This paper gives an overview of the design and wind tunnel test results of the wind turbine dedicated airfoils developed by Delft University of Technology (DUT). The DU-airfoils range in maximum relative thickness from 15% to 40% chord. The first designs were made with XFOIL. Since 1995 RFOIL was used, a modified version of XFOIL, featuring an improved prediction around the maximum lift coefficient and capabilities of predicting the effect of rotation on airfoil characteristics. The measured effect of Gurney flaps, trailing edge wedges, vortex generators and trip wires on the airfoil characteristics of various DU-airfoils is presented. Furthermore, a relation between the thickness of the airfoil leading edge and the angle-of-attack for leading edge separation is given.

Download Full-text

Rancang Bangun Piranti Lunak Pengolah Data Pasca Pengujian Terowongan Angin Kecepatan Rendah Indonesia

Jurnal ULTIMATICS ◽

10.31937/ti.v7i2.360 ◽

2016 ◽

Vol 7 (2) ◽

pp. 131-138

Author(s):

Ivransa Zuhdi Pane

Keyword(s):

Wind Tunnel ◽

Wind Tunnel Test ◽

Test Results ◽

Effective Solution ◽

Post Processing ◽

Prototype Development ◽

Design Activities ◽

Index Terms ◽

Test Objects ◽

Processing Requirement

Data post-processing plays important roles in a wind tunnel test, especially in supporting the validation of the test results and further data analysis related to the design activities of the test objects. One effective solution to carry out the data post-processing in an automated productive manner, and thus eliminate the cumbersome conventional manual way, is building a software which is able to execute calculations and have abilities in presenting and analyzing the data in accordance with the post-processing requirement. Through several prototype development cycles, this work attempts to engineer and realize such software to enhance the overall wind tunnel test activities. Index Terms—software engineering, wind tunnel test, data post-processing, prototype, pseudocode

Download Full-text

Investigation of the Time Dependence of Wind-Induced Aeroelastic Response on a Scale Model of a High-Rise Building

Applied Sciences ◽

10.3390/app11083315 ◽

2021 ◽

Vol 11 (8) ◽

pp. 3315

Author(s):

Fabio Rizzo

Keyword(s):

Wind Tunnel ◽

Time Dependence ◽

Wind Tunnel Test ◽

Structural Response ◽

Cumulative Distribution ◽

Scale Model ◽

Acquisition Time ◽

Test Results ◽

High Rise ◽

High Rise Building

Experimental wind tunnel test results are affected by acquisition times because extreme pressure peak statistics depend on the length of acquisition records. This is also true for dynamic tests on aeroelastic models where the structural response of the scale model is affected by aerodynamic damping and by random vortex shedding. This paper investigates the acquisition time dependence of linear transformation through singular value decomposition (SVD) and its correlation with floor accelerometric signals acquired during wind tunnel aeroelastic testing of a scale model high-rise building. Particular attention was given to the variability of eigenvectors, singular values and the correlation coefficient for two wind angles and thirteen different wind velocities. The cumulative distribution function of empirical magnitudes was fitted with numerical cumulative density function (CDF). Kolmogorov–Smirnov test results are also discussed.

Download Full-text

Experimental investigations of flow over NACA airfoils 0021 and 4412 of wind turbine blades with and without Tubercles

Wind Engineering ◽

10.1177/0309524x211007178 ◽

2021 ◽

pp. 0309524X2110071

Author(s):

Usman Butt ◽

Shafqat Hussain ◽

Stephan Schacht ◽

Uwe Ritschel

Keyword(s):

Wind Tunnel ◽

Drag Coefficient ◽

Wind Turbine ◽

Critical Region ◽

Lift Coefficient ◽

Turbine Blades ◽

Leading Edge ◽

Reynolds Numbers ◽

Experimental Investigations ◽

Wind Turbine Blades

Experimental investigations of wind turbine blades having NACA airfoils 0021 and 4412 with and without tubercles on the leading edge have been performed in a wind tunnel. It was found that the lift coefficient of the airfoil 0021 with tubercles was higher at Re = 1.2×105 and 1.69×105 in post critical region (at higher angle of attach) than airfoils without tubercles but this difference relatively diminished at higher Reynolds numbers and beyond indicating that there is no effect on the lift coefficients of airfoils with tubercles at higher Reynolds numbers whereas drag coefficient remains unchanged. It is noted that at Re = 1.69×105, the lift coefficient of airfoil without tubercles drops from 0.96 to 0.42 as the angle of attack increases from 15° to 20° which is about 56% and the corresponding values of lift coefficient for airfoil with tubercles are 0.86 and 0.7 at respective angles with18% drop.

Download Full-text