The Experts below are selected from a list of 8541 Experts worldwide ranked by ideXlab platform
David Lentink - One of the best experts on this subject based on the ideXlab platform.
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the Aerodynamic Force platform as an ergometer
The Journal of Experimental Biology, 2020Co-Authors: Marc E Deetjen, Diana D Chin, David LentinkAbstract:Animal flight requires Aerodynamic power, which is challenging to determine accurately in vivo. Existing methods rely on approximate calculations based on wake flow field measurements, inverse dynamics approaches, or invasive muscle physiological recordings. In contrast, the external mechanical work required for terrestrial locomotion can be determined more directly by using a Force platform as an ergometer. Based on an extension of the recent invention of the Aerodynamic Force platform, we now present a more direct method to determine the in vivo Aerodynamic power by taking the dot product of the Aerodynamic Force vector on the wing with the representative wing velocity vector based on kinematics and morphology. We demonstrate this new method by studying a slowly flying dove, but it can be applied more generally across flying and swimming animals as well as animals that locomote over water surfaces. Finally, our mathematical framework also works for power analyses based on flow field measurements.
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design and analysis of Aerodynamic Force platforms for free flight studies
Bioinspiration & Biomimetics, 2017Co-Authors: Ben Hightower, Andreas F. Haselsteiner, Rivers Ingersoll, Diana D Chin, Carl Lawhon, David LentinkAbstract:: We describe and explain new advancements in the design of the Aerodynamic Force platform, a novel instrument that can directly measure the Aerodynamic Forces generated by freely flying animals and robots. Such in vivo recordings are essential to better understand the precise Aerodynamic function of flapping wings in nature, which can critically inform the design of new bioinspired robots. By designing the Aerodynamic Force platform to be stiff yet lightweight, the natural frequencies of all structural components can be made over five times greater than the frequencies of interest. The associated high-frequency noise can then be filtered out during post-processing to obtain accurate and precise Force recordings. We illustrate these abilities by measuring the Aerodynamic Forces generated by a freely flying bird. The design principles can also be translated to other fluid media. This offers an opportunity to perform high-throughput, real-time, non-intrusive, and in vivo comparative biomechanical measurements of Force generation by locomoting animals and robots. These recordings can include complex bimodal terrestrial, aquatic, and aerial behaviors, which will help advance the fields of experimental biology and bioinspired design.
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In vivo recording of Aerodynamic Force with an Aerodynamic Force platform: From drones to birds
Journal of the Royal Society Interface, 2015Co-Authors: David Lentink, Andreas F. Haselsteiner, Rivers IngersollAbstract: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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In vivo recording of Aerodynamic Force with an Aerodynamic Force platform
arXiv: Fluid Dynamics, 2014Co-Authors: David Lentink, Andreas F. Haselsteiner, Rivers IngersollAbstract:Flapping wings enable flying animals and biomimetic robots to generate elevated Aerodynamic Forces. Measurements that demonstrate this capability are based on tethered experiments with 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 nonintrusive 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, which demonstrates that its upstroke is inactive.
Rivers Ingersoll - One of the best experts on this subject based on the ideXlab platform.
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design and analysis of Aerodynamic Force platforms for free flight studies
Bioinspiration & Biomimetics, 2017Co-Authors: Ben Hightower, Andreas F. Haselsteiner, Rivers Ingersoll, Diana D Chin, Carl Lawhon, David LentinkAbstract:: We describe and explain new advancements in the design of the Aerodynamic Force platform, a novel instrument that can directly measure the Aerodynamic Forces generated by freely flying animals and robots. Such in vivo recordings are essential to better understand the precise Aerodynamic function of flapping wings in nature, which can critically inform the design of new bioinspired robots. By designing the Aerodynamic Force platform to be stiff yet lightweight, the natural frequencies of all structural components can be made over five times greater than the frequencies of interest. The associated high-frequency noise can then be filtered out during post-processing to obtain accurate and precise Force recordings. We illustrate these abilities by measuring the Aerodynamic Forces generated by a freely flying bird. The design principles can also be translated to other fluid media. This offers an opportunity to perform high-throughput, real-time, non-intrusive, and in vivo comparative biomechanical measurements of Force generation by locomoting animals and robots. These recordings can include complex bimodal terrestrial, aquatic, and aerial behaviors, which will help advance the fields of experimental biology and bioinspired design.
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In vivo recording of Aerodynamic Force with an Aerodynamic Force platform: From drones to birds
Journal of the Royal Society Interface, 2015Co-Authors: David Lentink, Andreas F. Haselsteiner, Rivers IngersollAbstract: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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In vivo recording of Aerodynamic Force with an Aerodynamic Force platform
arXiv: Fluid Dynamics, 2014Co-Authors: David Lentink, Andreas F. Haselsteiner, Rivers IngersollAbstract:Flapping wings enable flying animals and biomimetic robots to generate elevated Aerodynamic Forces. Measurements that demonstrate this capability are based on tethered experiments with 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 nonintrusive 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, which demonstrates that its upstroke is inactive.
Renato Tognaccini - One of the best experts on this subject based on the ideXlab platform.
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Aerodynamic Force breakdown in reversible and irreversible components by vortex Force theory
AIAA Journal, 2019Co-Authors: Lin L Kang, Renato Tognaccini, Lorenzo Russo, Jie Z Wu, Wei D SuAbstract:A recently proposed Aerodynamic Force theory of compressible high-Reynolds-number flows based on the concept of vortex Force is here analyzed. The Aerodynamic Force is obtained by means of volume a...
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Aerodynamic Force and Lamb vector field in compressible unsteady flows
2018 AIAA Aerospace Sciences Meeting, 2018Co-Authors: Mario Ostieri, Renato Tognaccini, Didier Bailly, Daniel DestaracAbstract:A vorticity based theory for the computation and analysis of the Aerodynamic Force in steady and unsteady compressible flows is presented. It is the extension of a recent decomposition developed for incompressible flows. The breakdown in reversible and irreversible contributions is presented and a comparison with an unsteady thermodynamic drag breakdown is discussed. In particular, two physically completely different flows are analyzed: a pitching airfoil in subsonic flows and an airfoil natural buffet. A sensitivity analysis of the vortical method on the total Force computation is presented. Then the breakdown results are compared and discussed.
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linear and nonlinear decomposition of Aerodynamic Force acting on an oscillating plate
AIAA Journal, 2017Co-Authors: Mario Ostieri, Benedetto Mele, Renato TognacciniAbstract:An exact Lamb vector-based theory for the computation and decomposition of the Aerodynamic Force in unsteady viscous flows is presented and analyzed. This decomposition allows for a correct and str...
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A novel mid-field breakdown of the Aerodynamic Force in compressible flows
34th AIAA Applied Aerodynamics Conference, 2016Co-Authors: Mario Ostieri, Renato Tognaccini, Benedetto MeleAbstract:A vorticity based exact theory for the computation and breakdown of the Aerodynamic Force is here applied to the analysis of three-dimensional aircraft configurations in steady transonic flow conditions by post-processing numerical CFD solutions. A rigorous and unambiguous definition of lift-induced drag in compressible flows and its distinction from the profile components (viscous and wave) has been obtained. The equation is based on field integrals of the Lamb vector field, the cross product of vorticity times velocity. It highlights the generation of the Aerodynamic Force in the rotational part of the flow only (mid field formula).\ud The encountered numerical difficulties are described; they arise in particular when the freestream Mach number approaches one. They have been overcome by a proper treatment of the numerical integration in the shock region where the accuracy of the numerical flow solution is poorer. Thus, a new exact formula is obtained for an accurate Aerodynamic Force computation in high transonic and supersonic flows.\ud Applications are shown in the case of two-dimensional airfoil, elliptic wing (in transonic flow) and for the NASA CRM wing-body configuration. Comparisons with with classical drag breakdown methods based on the entropy drag concept are also presented and the improvements obtained in particular in the lift induced drag analysis are discussed
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vorticity based breakdown of the Aerodynamic Force in three dimensional compressible flows
AIAA Journal, 2016Co-Authors: Benedetto Mele, Mario Ostieri, Renato TognacciniAbstract:Recently, a definition of the lift-induced drag in terms of a field integral of the Lamb vector has been proposed in case of incompressible high-Reynolds-number flow and verified by postprocessing computational-fluid-dynamics solutions around wings. The possibility to extend this definition also to the case of compressible flows is investigated in this paper. An exact expression of the Aerodynamic Force in three-dimensional flows is discussed; it allows for a breakdown of the Aerodynamic Force (both drag and lift) in its physical contributions. Its applicability is analyzed in case of Reynolds-averaged Navier–Stokes numerical solutions around an elliptic wing in subsonic and transonic conditions. A rigorous and unambiguous definition of lift-induced drag is obtained. It still depends on the vortex Force of the flow (the volume integral of the Lamb vector field), but a compressibility correction term is also to be taken into account. Both viscous and wave drag components can be computed by a surface integr...
Huan Fuming - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Stability of Elastic Vehicles with Unsteady Aerodynamic Force Modeling
1991 American Control Conference, 1991Co-Authors: Chen Shilu, Yan Hengyuan, Huo Xiufang, Huan FumingAbstract:In this paper, stability problem of elastic vehicle is studied with the effect of unsteady Aerodynamic Forces considered. Longitudinal equations of disturbance motions with the actions of unsteady Aerodynamic Force are derived. A method of analysis of the effect of aeroelasticity on the stability of elastic vehicle by using a simplified mathematical model of unsteady Aerodynamic Forces is proposed.
Andreas F. Haselsteiner - One of the best experts on this subject based on the ideXlab platform.
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design and analysis of Aerodynamic Force platforms for free flight studies
Bioinspiration & Biomimetics, 2017Co-Authors: Ben Hightower, Andreas F. Haselsteiner, Rivers Ingersoll, Diana D Chin, Carl Lawhon, David LentinkAbstract:: We describe and explain new advancements in the design of the Aerodynamic Force platform, a novel instrument that can directly measure the Aerodynamic Forces generated by freely flying animals and robots. Such in vivo recordings are essential to better understand the precise Aerodynamic function of flapping wings in nature, which can critically inform the design of new bioinspired robots. By designing the Aerodynamic Force platform to be stiff yet lightweight, the natural frequencies of all structural components can be made over five times greater than the frequencies of interest. The associated high-frequency noise can then be filtered out during post-processing to obtain accurate and precise Force recordings. We illustrate these abilities by measuring the Aerodynamic Forces generated by a freely flying bird. The design principles can also be translated to other fluid media. This offers an opportunity to perform high-throughput, real-time, non-intrusive, and in vivo comparative biomechanical measurements of Force generation by locomoting animals and robots. These recordings can include complex bimodal terrestrial, aquatic, and aerial behaviors, which will help advance the fields of experimental biology and bioinspired design.
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In vivo recording of Aerodynamic Force with an Aerodynamic Force platform: From drones to birds
Journal of the Royal Society Interface, 2015Co-Authors: David Lentink, Andreas F. Haselsteiner, Rivers IngersollAbstract: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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In vivo recording of Aerodynamic Force with an Aerodynamic Force platform
arXiv: Fluid Dynamics, 2014Co-Authors: David Lentink, Andreas F. Haselsteiner, Rivers IngersollAbstract:Flapping wings enable flying animals and biomimetic robots to generate elevated Aerodynamic Forces. Measurements that demonstrate this capability are based on tethered experiments with 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 nonintrusive 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, which demonstrates that its upstroke is inactive.