Wind tunnel tests

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Membrane Deflection and Fastener Load Data Measured During the October 1995 Wind Tunnel Tests on a Mechanically-Attached EPDM Single-Ply Roofing System

Membrane Deflection and Fastener Load Data Measured During the October 1995 Wind Tunnel Tests on a Mechanically-Attached EPDM Single-Ply Roofing System

https://doi.org/10.4224/20338238 Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Membrane Deflection and Fastener Load Data Measured During the October 1995 Wind Tunnel Tests on a Mechanically-Attached EPDM Single-Ply Roofing System

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Morphing wing-tip open loop controller and its validation during wind tunnel tests at the IAR-NRC

Morphing wing-tip open loop controller and its validation during wind tunnel tests at the IAR-NRC

Abstract: In this project, a wing tip of a real aircraft was designed and manufactured. This wing tip was composed of a wing and an aileron. The wing was equipped with a composite skin on its upper surface. This skin changed its shape (morphed) by use of 4 electrical in-house developed actuators and 32 pressure sensors. These pressure sensors measure the pressures, and further the loads on the wing upper surface. Thus, the upper surface of the wing was morphed using these actuators with the aim to improve the aerodynamic performances of the wing-tip. Two types of ailerons were designed and manufactured: one aileron is rigid (non-morphed) and one morphing aileron. This morphing aileron can change its shape also for the aerodynamic performances improvement. The morphing wing-tip internal structure is designed and manufactured, and is presented firstly in the paper. Then, the modern communication and control hardware are presented for the entire morphing wing tip equipped with actuators and sensors having the aim to morph the wing. The calibration procedure of the wing tip is further presented, followed by the open loop controller results obtained during wind tunnel tests. Various methodologies of open loop control are presented in this paper, and results obtained were obtained and validated experimentally through wind tunnel tests.
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Morphing wing real time optimization in wind tunnel tests

Morphing wing real time optimization in wind tunnel tests

Mahmoud Mamou 4 , Youssef Mébarki 5 Institute for Aerospace Research, NRC, Ottawa, Ontario, K1A 0R6, Canada In this paper, wind tunnel results of a real time optimization of a morphing wing in wind tunnel for delaying the transition towards the trailing edge are presented. A morphing rectangular finite aspect ratio wing, having a WTEA reference airfoil cross-section, was considered with its upper surface made of a flexible composite material and instrumented with Kulite pressure sensors, and two smart memory alloys actuators. Several wind tunnel tests runs for various Mach numbers, angles of attack and Reynolds numbers were performed in the 6’×9’ wind tunnel at the Institute for Aerospace Research at the National Research Council Canada (IAR/NRC). Unsteady pressure signals were recorded and used as feed back in real time control while the morphing wing was requested to reproduce various optimized airfoils by changing automatically the two actuators strokes. The paper shows the optimization method implemented into the control software code that allows the morphing wing to adjust its shape to an optimum configuration under the wind tunnel airflow conditions.
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Fastener Load Data Measured During the November 1994 Wind Tunnel Tests on a Mechanically-Attached PVC Single-Ply Roofing System

Fastener Load Data Measured During the November 1994 Wind Tunnel Tests on a Mechanically-Attached PVC Single-Ply Roofing System

https://doi.org/10.4224/20338198 Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Fastener Load Data Measured During the November 1994 Wind Tunnel Tests on a Mechanically-Attached PVC Single-Ply Roofing System

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Snow drifts on flat roofs : wind tunnel tests and field measurements

Snow drifts on flat roofs : wind tunnel tests and field measurements

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Snow drifts on flat roofs : wind tunnel tests and field measurements da Matha Sant'Anna, F.; Taylor, D. A. https://publications-cnrc.canada.ca/fra/droits

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Boundary layer behaviour on a morphing airfoil: simulation and wind tunnel tests

Boundary layer behaviour on a morphing airfoil: simulation and wind tunnel tests

WIND TUNNEL TESTS RESULTS The wind tunnel tests were performed at the 2x3m atmospheric closed circuit wind tunnel of the Institute for Aerospace Research of the National Research Council Canada. The tunnel test section allows wind speed up to Mach=0.3 at atmospheric pressure. The wind tunnel model is a rectangular plan form wing consisting of rigid and flexible parts. The rigid body was equipped with static pressure taps. The upper surface flexible skin was instrumented with 16 Kulite transducers, for transition detection. The sensors were installed on a diagonal line in order to avoid turbulent contamination of the downstream sensors. The Kulite XCQ-062 series sensors are used and they are 0.066 inch in diameter. They did not contaminate the flow for the tests conditions, except when leaking problems occurred. The sensors have a 5 psi differential pressure range with infinitesimal resolution and a natural frequency range up to 150 kHz. They were installed within a cavity buried below the flexible skin surface and connected to the surface flow through a mall pressure tap of 0.020 inch, to avoid flow contamination. The data acquisition sampling rate was set to 10 kHz per channel over 16 channels due to acquisition system limitation of 160 kHz. The laminar to turbulent transition was detected by analysing the unsteady signal through Fast Fourier Transform (FFT) spectral decomposition. A rise in amplitudes of the signals in the neighbourhood of 4 kHZ frequency indicates the occurrence of the Tollmien-Schlichting waves that trigger the transition on the sensor location and subsequently the turbulent flow in the downstream of the sensor location. The RMS, which is the standard deviation of the pressure signal values with respect to the mean value for a high pass filtered signal at 1 kHz, was used as a quantifier of the pressure signal variations amplitudes [7].
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Numerical simulation and wind tunnel tests investigation and validation of a morphing wing-tip demonstrator aerodynamic performance

Numerical simulation and wind tunnel tests investigation and validation of a morphing wing-tip demonstrator aerodynamic performance

Infra-red tests Wind tunnel tests Laminar-to-turbulent flow transition This paper presents the results obtained from the numerical simulation and experimental wind tunnel testing of a morphing wing equipped with a flexible upper surface and controllable actuated aileron. The technology demonstrator is representative of a real aircraft wing tip section, and it was developed following a complex, multidisciplinary design process. The model was fitted with a composite material upper skin whose shape can be morphed, as a function of the flight condition, by four electrical actuators placed inside the wing structure. The optimizations were performed with the aim of controlling the extent of the laminar flow region, and the resulting shapes were scanned using high-precision photogrammetry. The numerical simulations were performed using Computational Fluid Dynamics (CFD) and included a model for predicting the laminar-to-turbulent flow transition over the entire wing surface. The analyses included cases with three aileron deflection angles and angles of attack situated within five degrees range. The CFD results were compared with infrared thermography measurements in terms of transition location, surface pressure measurements and balance loads measurements acquired during subsonic wind tunnel tests performed at the National Research Council Canada.
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Proportional fuzzy feed-forward architecture control validation by wind tunnel tests of a morphing wing

Proportional fuzzy feed-forward architecture control validation by wind tunnel tests of a morphing wing

21 trol the positions of the actuators in real time in order to obtain and to maintain the desired shape 22 of the wing for a specified flight condition. The feasibility and effectiveness of the developed control 23 system by use of a proportional fuzzy feed-forward methodology are demonstrated experimentally 24 through bench and wind tunnel tests of the morphing wing model.

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A CFD approach to improve wind tunnel tests - The hepia global methodology

A CFD approach to improve wind tunnel tests - The hepia global methodology

THE USE OF CFD IN THE HEPIA METHODOLOGY This project demonstrates the hepia global approach is very robust and consistent. In this project, 90% of the work has been done in CFD. However, the role of the wind tunnel was important : • To validate the CFD method (mesh, model choices) • To validate some data regarding modelized

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Wind 
            tunnel testing of low consumption vehicle consomini

Wind tunnel testing of low consumption vehicle consomini

Aerodynamics The aerodynamics was developed by the CMEFE of Ecole d'Ingénieurs de Genève. Design and aerodynamics were studied using an experimental approach. Models were built to perform wind tunnel tests. The regions where a separation of the flow can occur were investigated using visualization methods and pressure measurements. The forces and moments, essentially the drag and the lift, were measured using six components balances developed at the CMEFE. During a first step a 1/8 scale model is built based upon expertise and specifications. Then, preliminary tests are done in a small wind tunnel. This approach reduces significantly the costs.
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Wind-tunnel pressure measurements on model-scale rigid downwind sails

Wind-tunnel pressure measurements on model-scale rigid downwind sails

Sail pressure distributions can be measured in model- scale from wind tunnel tests and in full scale [11]. The state-of-the-art experimental technique is based on flexible sails – including semi-flexible single-skin fibreglass sails used by Richards and Lasher [9], and common spinnaker sailcloth used by Viola & Flay [10,12] - where pressure taps are attached to one side of the sail and pressures are measured on the other side of the sail through holes in the sailcloth. This technique allows realistic sail trims in different sailing conditions to be modelled, but is limited by (i) the unknown blockage effect due to the tubes and pressure taps, (ii) the alteration of both the static sail shape and the dynamic behaviour of the sails by the mass and stiffness of the tubes and pressure taps, (iii) the low accuracy in the reconstruction of the sail flying shape.
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2016 — Morphing wing system integration with wind tunnel testing

2016 — Morphing wing system integration with wind tunnel testing

81 expected to occur in this zone of the wing upper surface by the use of these sensors. Here, the sensor installation and data acquisition were the responsibility of the LARCASE team. Once proper installation of the wing, aileron and hardware were verified and performed well, the preliminary preparations took place before the actual tests. The NRC team had to confirm the efficiency and readiness of their wind tunnel control system and data acquisition. Generally, four people were directly involved in test operations: an NRC Test Engineer and Wind Tunnel Operator, and three LARCASE students responsible for wing system control and aileron accelerometer monitoring. In fact, before performing tests on the wing model, our team was obliged by the NRC team to adopt some safety measures; for example, one measure recommended by the NRC team was the ‘close monitoring’ of aileron flutter during tests in order to detect the occurrence of sudden events. As previously mentioned, one student of our team had to receive accelerometer signals and visualise the acceleration amplitudes in three directions. Data was also logged for further analysis after the wind tunnel tests. Another safety measure was an emergency button that, when activated, cut immediately electrical power to the aileron actuator.
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Upwind sail aerodynamics : A RANS numerical investigation validated with wind tunnel pressure measurements

Upwind sail aerodynamics : A RANS numerical investigation validated with wind tunnel pressure measurements

The contribution of this paper is that RANS simulations on upwind sails are, for the first time, validated with local pressure measurements on fully three-dimensional model-scale sails. In previous works, validation was performed with global quantities such as the aerodynamic forces on the sails (Lasher and Richards, 2007; Viola, 2009), or on a bi-dimensional sail section (Caponnetto and Castelli, 1998, using the data from Wilkinson, 1984). The aim of this work is to develop a reliable RANS simulation on upwind sails with a thorough validation with experimental data and to gain new insights on the flow field correlated with the measured surface pressure distributions. The present work is part of a wide reaching project headed by the first author, investigating sail aerodynamics through full-scale on-water experiments, model-scale wind-tunnel tests and CFD analysis for upwind and downwind conditions (Viola and Flay, 2011a).
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2019 — Improvement of subsonic wall corrections in an industrial wind tunnel

2019 — Improvement of subsonic wall corrections in an industrial wind tunnel

In an initial stage, the computational data generated has been applied to validate the one-variable method without the need for experimental wind-tunnel data. Particularly, numerical results calculated for the 2.7% scale semispan NASA Common Research Model (CRM), in its wing/body configuration, have been employed. The validation approach has consisted of modifying the wall-correction methodology to take high fidelity free-air CFD results as measured wind-tunnel data and then comparing it to the free-air potential theory representation of the test article typically employed by the one-variable method, the objective being to obtain ΔM and Δα “zero-corrections” for every data point studied. The quality of the results has been assessed based on uncertainty budgets for high lift testing applications taken from Steinle and Stanewsky (1982), revealing that although the one-variable method is reliable in attached-flow conditions it lacks accuracy when flow separation develops on the test article. It has been understood that improving the potential-theory representation of the test article currently applied at the NRC 5ft TWT should improve the overall wall-correction methodology. To this end, the issues with the model representation at high angle of attack and in stall conditions have been addressed. First, a (Euler) CFD-based study of the potential theory representation of the fuselage currently used at the NRC 5ft TWT has been performed. As a result, the current Rankine body fuselage representation has been replaced by a new fuselage representation consisting of n sources/sinks and n doublets evenly distributed at n locations over the fuselage centerline, that provides an accurate representation of the flow around a pitching fuselage in the farfield. This updated fuselage representation is ready to be implemented in real wind-tunnel tests. The repercussions of replacing the Rankine body representation of the fuselage by its updated version are not likely to be significant to wind-tunnel tests using a complete aircraft half-model, but could have a greater importance for wind-tunnel tests where the test article is essentially a large scale body of revolution (e.g. a missile).
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2016 — Design, development and tests in real time of control methodologies for a morphing wing in wind tunnel

2016 — Design, development and tests in real time of control methodologies for a morphing wing in wind tunnel

• More efficient propulsion systems, • Integration of light weight materials in aircraft manufacturing, • Improved aircraft flight trajectories. According to the classification proposed in the IATA report, some of these technologies need to be integrated into future aircraft. This integration becomes a great challenge for airplane manufacturers as they face issues of compatibility, reliability, profitability and certification for their systems. The ideal consensus for solving these problems is the manufacturing of a large-scale prototype, which can be tested and validated by experimental wind tunnel testing and further by flight tests. Thus, the CRIAQ MDO505 project was launched in 2012 and brought together students, researchers, and industrial experts to achieve the common goal of reducing aircraft fuel consumption by reducing its drag through an active morphing structure. Drag reduction was further validated experimentally by wind tunnel tests. The wing drag reduction was achieved by moving the laminar/turbulent flow transition region towards the wing trailing edge. The delaying of the flow transition allowed to obtain an extended laminar flow on the upper surface. Changes of the configuration of the wing airfoil had effects on the lift, and drag loads, as well as on the flow transition region. The turbulent flow was minimized as much as possible, thus less drag, and fuel consumption are obtained.
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Wind-tunnel pressure measurements on model-scale rigid downwind sails

Wind-tunnel pressure measurements on model-scale rigid downwind sails

Sail pressure distributions can be measured in model-scale from wind tunnel tests and in full scale [Viola and Flay 2011]. The state-of-the-art experimental technique is based on flexible sails – including semi-flexible single-skin fibreglass sails used by Richards and Lasher [Richard and Lasher 2008], and common spinnaker sailcloth used by Viola & Flay [Viola and Flay 2009, 2010] - where pressure taps are attached to one side of the sail and pressures are measured on the other side of the sail through holes in the sailcloth. This technique allows realistic sail trims in different sailing conditions to be modelled, but is limited by (i) the unknown blockage effect due to the tubes and pressure taps, (ii) the alteration of both the static sail shape and the dynamic behaviour of the sails by the mass and stiffness of the tubes and pressure taps, (iii) the low accuracy in the reconstruction of the sail flying shape.
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Wind-tunnel investigations of an inclined stay cable with a helical fillet

Wind-tunnel investigations of an inclined stay cable with a helical fillet

amplitude of the cable vibrations observed were greatly influenced by the geometry of the HDPE tube, even with the helical fillet in place, whereby a rotation of the cable model on its longitudinal axis could translate in vibrations with unacceptable amplitudes or vibrations with small amplitude. Observation i) is new, i.e. it has not been reported elsewhere. It was not expected since the general belief was that the helical fillet would reduce the sensitivity of the aerodynamics of the model to Reynolds number effects in the critical regime, which is believed to be one of the primary cause of inclined cable galloping. It might explain observations of stay cable vibrations of cables with a helical fillet in dry conditions as reported in field measurement campaigns. The oscillations were not caused by buffeting due to turbulence and were similar to the limited amplitude responses described in Cheng et al. (2003). It was observed that the cable model with the helical fillet experienced a drag crisis almost as pronounced as for a smooth cable, however the oscillations occurred at a wind speed above 25 m/s corresponding to a Reynolds number regime (super-critical) where the cross-sectional force coefficients did not vary significantly with wind speed as shown in Figure 3.
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Implementation of a hybrid electro-active actuated morphing wing in wind tunnel

Implementation of a hybrid electro-active actuated morphing wing in wind tunnel

Keywords: Aerodynamics, Morphing, Piezoelectricity, Shape-memory Alloys, Control. Abstract. Amongst current aircraft research topics, morphing wing is of great interest for improving the aerodynamic performance. A morphing wing prototype has been designed for wind tunnel experiments. The rear part of the wing - corresponding to the retracted flap - is actuated via a hybrid actuation system using both low frequency camber control and a high frequency vibrating trailing edge. The camber is modified via surface embedded shape memory alloys. The trailing edge vibrates thanks to piezoelectric macro-fiber composites. The actuated camber, amplitude and frequency ranges are characterized. To accurately control the camber, six independent shape memory alloy wires are controlled through nested closed-loops. A significant reduction in power consumption is possible thanks this control strategy. The effects on flow via morphing have been measured during wind tunnel experiments. This low scale mock-up aims to demonstrate the hybrid morphing concept, according to actuator capabilities point of view as well as aerodynamic performance.
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To curl or not to curl : wind tunnel investigation of spinnaker performance

To curl or not to curl : wind tunnel investigation of spinnaker performance

2 EXPERIMENTAL APPARATUS 2.1 WIND TUNNEL The experimental campaign was carried out in 2016 in the Twisted Flow Wind Tunnel ([11]) of the University of Auck- land, New Zealand illustrated in Fig. 2, thanks to the Sail- ing Fluids collaboration program. The model was set up onto a balance (described in [2]) which can measure the different aerodynamic forces. The open jet testing section is 7 meter wide by 3.5 meter high. This paper focuses onto the drive

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Implementation of a hybrid electro-active actuated morphing wing in wind tunnel

Implementation of a hybrid electro-active actuated morphing wing in wind tunnel

Wind tunnel experiments have demonstrated the ability of the camber control to change the lift by 23%, the drag by 35% and the lift over drag ratio by 16%. In addition, the vibrating trailing edge is able to add some per cent gains to the achieve modifications by camber control. The main objective of this study is to develop tools to design a true scale electroactive hybrid morphing flap. The next step is to post-process all the recorded data during wind-tunnel experiments.

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