Dynamic lift measurements on a FX79W151A airfoil via pressure distribution on the wind tunnel walls

Wolken-Möhlmann, Gerrit; Knebel, Pascal; Barth, S.; Peinke, Joachim

doi:10.1088/1742-6596/75/1/012026

Cited by 10 publications

(11 citation statements)

References 3 publications

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“…The main difference between an AFP and terrestrial force plate is that AFPs are much more sensitive to pressure per unit surface area. This sensitivity also makes the AFP applicable to wind tunnels in which they could integrate the wall pressure distribution to determine the vertical aerodynamic force [ 33 ]. Theoretically, this real-time method should work for many animals, robots and objects that generate a net force in a fluid.…”

Section: In Vivo Demonstration and Outlookmentioning

confidence: 99%

In vivorecording of aerodynamic force with an aerodynamic force platform: from drones to birds

Lentink

Haselsteiner

Ingersoll

2015

J. R. Soc. Interface.

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Flapping wings enable flying animals and biomimetic robots to generate elevated aerodynamic forces. Measurements that demonstrate this capability are based on experiments with tethered robots and animals, and indirect force calculations based on measured kinematics or airflow during free flight. Remarkably, there exists no method to measure these forces directly during free flight. Such in vivo recordings in freely behaving animals are essential to better understand the precise aerodynamic function of their flapping wings, in particular during the downstroke versus upstroke. Here, we demonstrate a new aerodynamic force platform (AFP) for non-intrusive aerodynamic force measurement in freely flying animals and robots. The platform encloses the animal or object that generates fluid force with a physical control surface, which mechanically integrates the net aerodynamic force that is transferred to the earth. Using a straightforward analytical solution of the Navier–Stokes equation, we verified that the method is accurate. We subsequently validated the method with a quadcopter that is suspended in the AFP and generates unsteady thrust profiles. These independent measurements confirm that the AFP is indeed accurate. We demonstrate the effectiveness of the AFP by studying aerodynamic weight support of a freely flying bird in vivo. These measurements confirm earlier findings based on kinematics and flow measurements, which suggest that the avian downstroke, not the upstroke, is primarily responsible for body weight support during take-off and landing.

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Section: In Vivo Demonstration and Outlookmentioning

confidence: 99%

In vivorecording of aerodynamic force with an aerodynamic force platform: from drones to birds

Lentink

Haselsteiner

Ingersoll

2015

J. R. Soc. Interface.

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“…Measurements were performed in the closed test section (nozzle area of 1.0 m × 0.8 m, length of 2.0 m) of the closed loop wind tunnel of the University of Oldenburg (for further details of the setup see [4]). Wind speeds up to 50 m/s were reached.…”

Section: Methodsmentioning

confidence: 99%

Dynamic Stall Measurements

Schneemann

Wolken-Möhlmann

Peinke

2009

Proc Appl Math and Mech

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Forces acting statically on an airfoil in laminar flow are well known. Under turbulent conditions dynamic effects (like dynamic stall) take place. There are different theoretical models to describe dynamic stall, but very little experimental data. We present dynamic stall measurements using an FX 79-W-151A airfoil in a closed test section of a wind tunnel with laminar inflow. Dynamic stall was induced by pitching the foil sinusoidally. Lift forces were measured using the pressure distribution on the wind tunnel walls.

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“…In the NACA test, the lift is deduced from the pressure distributions measured on the aerofoil surfaces, and the drag is evaluated from the pressure in the wake (27) . Such methods allow the measuring devices to be placed near the centre of the wing span (28) , and hence the 3D effect can be significantly reduced, whereas in the present wind-tunnel test, all the forces are measured directly with the force balance and the forces on the wing tips are included. The mechanical clearance between the wing tips and splitters causes 3D effects that increase drag and reduce lift that leads to the difference in the results.…”

Section: Aerodynamic Performancementioning

confidence: 99%

A morphing aerofoil with highly controllable aerodynamic performance

Soutis

Zhong

et al. 2016

Aeronaut. j.

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In this paper, a morphing carbon fibre composite aerofoil concept with an active trailing edge is proposed. This aerofoil features of camber morphing with multiple degrees of freedom. The shape morphing is enabled by an innovative structure driven by an electrical actuation system that uses linear ultrasonic motors (LUSM) with compliant runners, enabling a full control of multiple degrees of freedom. The compliant runners also serve as structural components that carry the aerodynamic load and maintain a smooth skin curvature. The morphing structure with compliant truss is shown to exhibit a satisfactory flexibility and loading capacity in both numerical simulations and static loading tests. This design is capable of providing a pitching moment control independent of lift and higher L/D ratios within a wider range of angle of attack. Such multiple morphing configurations could expand the flight envelope of future unmanned aerial 2 vehicles. A small prototype is built to illustrate the concept but as no off-the-shelf LUSMs can be integrated into this bench top model, two servos are employed as actuators providing two controlled degrees of freedom. Keywords

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Dynamic lift measurements on a FX79W151A airfoil via pressure distribution on the wind tunnel walls

Cited by 10 publications

References 3 publications

In vivorecording of aerodynamic force with an aerodynamic force platform: from drones to birds

In vivorecording of aerodynamic force with an aerodynamic force platform: from drones to birds

Dynamic Stall Measurements

A morphing aerofoil with highly controllable aerodynamic performance

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