The Experts below are selected from a list of 1773 Experts worldwide ranked by ideXlab platform
Eitelberg G. - One of the best experts on this subject based on the ideXlab platform.
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Numerical analysis of Propeller induced ground vortices by actuator disk model
2017Co-Authors: Yang Y., Veldhuis L.l.m., Eitelberg G.Abstract:Abstract: During the ground operation of aircraft, the interaction between the propulsor-induced flow field and the ground may lead to the generation of ground vortices. Utilizing numerical approaches, the source of vorticity entering ground vortices is investigated. The results show that the production of wall-parallel components of vorticity has a strong contribution from the wall-parallel components of the pressure gradient on the wall, which is generated by the action of the propulsor. This mechanism is a supplementation for the vorticity transported from the far-field boundary layer, which has been assumed the main vorticity source in a number of previous publications. Furthermore, the quantitative prediction of the occurrence of ground vortices is performed from the numerical results. As the distance of the Propeller form the ground decreases, and as the thrust of the Propeller increases, ground vortices are generated from the ground and enter the Propeller. In addition, the vortices which exist near the ground but does not enter the Propeller Plane are observed and visualized by three-dimensional data. Graphical abstract: [Figure not available: see fulltext.]
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Numerical analysis of Propeller induced ground vortices by actuator disk model
'Springer Science and Business Media LLC', 2017Co-Authors: Yang Y., Veldhuis L.l.m., Eitelberg G.Abstract:Abstract: During the ground operation of aircraft, the interaction between the propulsor-induced flow field and the ground may lead to the generation of ground vortices. Utilizing numerical approaches, the source of vorticity entering ground vortices is investigated. The results show that the production of wall-parallel components of vorticity has a strong contribution from the wall-parallel components of the pressure gradient on the wall, which is generated by the action of the propulsor. This mechanism is a supplementation for the vorticity transported from the far-field boundary layer, which has been assumed the main vorticity source in a number of previous publications. Furthermore, the quantitative prediction of the occurrence of ground vortices is performed from the numerical results. As the distance of the Propeller form the ground decreases, and as the thrust of the Propeller increases, ground vortices are generated from the ground and enter the Propeller. In addition, the vortices which exist near the ground but does not enter the Propeller Plane are observed and visualized by three-dimensional data. Graphical abstract: [Figure not available: see fulltext.]Flight Performance and Propulsio
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Propeller and inflow vortex interaction: vortex response and impact on the Propeller performance
'Springer Science and Business Media LLC', 2016Co-Authors: Yang Y., Veldhuis L.l.m., Zhou T, Sciacchitano A., Eitelberg G.Abstract:The aerodynamic operating conditions of a Propeller can include complex situations where vorticity from sources upstream can enter the Propeller Plane. In general, when the vorticity enters in a concentrated form of a vortex, the interaction between the vortex and blade is referred to as blade–vortex interaction or BVI. The interaction may affect the Propeller performance as well as its noise production. In the present paper, investigations of the interaction of a wing tip vortex generated by a lifting surface upstream of the rotor Plane and an eight-bladed Propeller are reported. Utilizing two ends of an upstream wing with non-symmetrical airfoil, the rotation of the incoming vortex could be made to co-rotate or to contra-rotate with the Propeller. The ensuing velocity fields were quantified with the help of particle image velocimetry (PIV), and the Propeller performance was evaluated with the help of a rotating shaft balance (RSB) mounted on the Propeller shaft. The results describe the displacement of the vortex core, as it moves through the rotor Plane as well as the positive effect on the thrust and torque of the contra-rotating vortex and the opposite of it in the case of the co-rotating vortex. The current research could be applied to analyse the influence of the incoming vortex on the Propeller, e.g., ground vortex, tip vortex shed from a control surface, etc.Flight Performance and PropulsionAerodynamic
Veldhuis L.l.m. - One of the best experts on this subject based on the ideXlab platform.
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Aerodynamic Loads on an Aft-Mounted Propeller Induced by the Wing Wake
'American Institute of Aeronautics and Astronautics (AIAA)', 2019Co-Authors: Van Arnhem N., Vos Roelof, Veldhuis L.l.m.Abstract:This paper presents an experimental and numerical study of the aerodynamic in-Plane and out-of-Plane loads of a Propeller which are induced by the wake of an upstream wing impinging on the lower half of the Propeller disk. A Propeller was installed behind a wing model in a low-speed wind-tunnel and measurements were taken with an external balance and a rotating shaft balance to determine the aerodynamic characteristics of the wing and Propeller. The installation of the wing shows negligible changes in Propeller thrust coefficient at low advance ratios, while at medium thrust conditions (C T ≈ 0.3), the wing shows a small increase in Propeller thrust in the order of 1%. The installation of the Propeller aft of the wing shows a change on Propeller efficiency ranging from ∆η p =–0.01 to +0.04. The location of the wake impingement at the Propeller Plane is shown to play an important factor for the time averaged and unsteady Propeller loads. The radial location where the largest change in load occurs due to wake impingement, coincides with the location of highest Propeller loading. A simplified and computationally efficient method is presented for estimation of these unsteady Propeller loads in non-uniform inflow. The method shows good agreement for the integral unsteady blade thrust and integral Propeller for different wake impingement locations. Accepted Author ManuscriptFlight Performance and Propulsio
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Aerodynamic Loads on an Aft-Mounted Propeller Induced by the Wing Wake
2019Co-Authors: Van Arnhem N., Vos Roelof, Veldhuis L.l.m.Abstract:This paper presents an experimental and numerical study of the aerodynamic in-Plane and outof- Plane loads of a Propeller which are induced by the wake of an upstream wing impinging on the lower half of the Propeller disk. A Propeller was installed behind a wing model in a low-speed wind-tunnel and measurements were taken with an external balance and a rotating shaft balance to determine the aerodynamic characteristics of the wing and Propeller. The installation of the wing shows negligible changes in Propeller thrust coe_cient at low advance ratios, while at medium thrust conditions (CT _ 0:3), the wing shows a small increase in Propeller thrust in the order of 1%. The installation of the Propeller aft of the wing shows a change on Propeller e_ciency ranging from __p=–0.01 to +0.04. The location of the wake impingement at the Propeller Plane is shown to play an important factor for the time averaged and unsteady Propeller loads. The radial location where the largest change in load occurs due to wake impingement, coincides with the location of highest Propeller loading. A simplified and computationally e_cient method is presented for estimation of these unsteady Propeller loads in non-uniform inflow. The method shows good agreement for the integral unsteady blade thrust and integral Propeller for di_erent wake impingement locations
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Numerical analysis of Propeller induced ground vortices by actuator disk model
2017Co-Authors: Yang Y., Veldhuis L.l.m., Eitelberg G.Abstract:Abstract: During the ground operation of aircraft, the interaction between the propulsor-induced flow field and the ground may lead to the generation of ground vortices. Utilizing numerical approaches, the source of vorticity entering ground vortices is investigated. The results show that the production of wall-parallel components of vorticity has a strong contribution from the wall-parallel components of the pressure gradient on the wall, which is generated by the action of the propulsor. This mechanism is a supplementation for the vorticity transported from the far-field boundary layer, which has been assumed the main vorticity source in a number of previous publications. Furthermore, the quantitative prediction of the occurrence of ground vortices is performed from the numerical results. As the distance of the Propeller form the ground decreases, and as the thrust of the Propeller increases, ground vortices are generated from the ground and enter the Propeller. In addition, the vortices which exist near the ground but does not enter the Propeller Plane are observed and visualized by three-dimensional data. Graphical abstract: [Figure not available: see fulltext.]
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Numerical analysis of Propeller induced ground vortices by actuator disk model
'Springer Science and Business Media LLC', 2017Co-Authors: Yang Y., Veldhuis L.l.m., Eitelberg G.Abstract:Abstract: During the ground operation of aircraft, the interaction between the propulsor-induced flow field and the ground may lead to the generation of ground vortices. Utilizing numerical approaches, the source of vorticity entering ground vortices is investigated. The results show that the production of wall-parallel components of vorticity has a strong contribution from the wall-parallel components of the pressure gradient on the wall, which is generated by the action of the propulsor. This mechanism is a supplementation for the vorticity transported from the far-field boundary layer, which has been assumed the main vorticity source in a number of previous publications. Furthermore, the quantitative prediction of the occurrence of ground vortices is performed from the numerical results. As the distance of the Propeller form the ground decreases, and as the thrust of the Propeller increases, ground vortices are generated from the ground and enter the Propeller. In addition, the vortices which exist near the ground but does not enter the Propeller Plane are observed and visualized by three-dimensional data. Graphical abstract: [Figure not available: see fulltext.]Flight Performance and Propulsio
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Propeller and inflow vortex interaction: vortex response and impact on the Propeller performance
'Springer Science and Business Media LLC', 2016Co-Authors: Yang Y., Veldhuis L.l.m., Zhou T, Sciacchitano A., Eitelberg G.Abstract:The aerodynamic operating conditions of a Propeller can include complex situations where vorticity from sources upstream can enter the Propeller Plane. In general, when the vorticity enters in a concentrated form of a vortex, the interaction between the vortex and blade is referred to as blade–vortex interaction or BVI. The interaction may affect the Propeller performance as well as its noise production. In the present paper, investigations of the interaction of a wing tip vortex generated by a lifting surface upstream of the rotor Plane and an eight-bladed Propeller are reported. Utilizing two ends of an upstream wing with non-symmetrical airfoil, the rotation of the incoming vortex could be made to co-rotate or to contra-rotate with the Propeller. The ensuing velocity fields were quantified with the help of particle image velocimetry (PIV), and the Propeller performance was evaluated with the help of a rotating shaft balance (RSB) mounted on the Propeller shaft. The results describe the displacement of the vortex core, as it moves through the rotor Plane as well as the positive effect on the thrust and torque of the contra-rotating vortex and the opposite of it in the case of the co-rotating vortex. The current research could be applied to analyse the influence of the incoming vortex on the Propeller, e.g., ground vortex, tip vortex shed from a control surface, etc.Flight Performance and PropulsionAerodynamic
Clothier R - One of the best experts on this subject based on the ideXlab platform.
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Acoustic signature measurement of small multi-rotor unmanned aircraft systems
Sage (United Kingdom), 2017Co-Authors: Kloet N, Watkins S, Clothier RAbstract:This work describes the testing involved in generating an acoustic signature profile of a small multi-rotor unmanned aircraft system. A typical multi-rotor unmanned aircraft system, with a weight of approximately 2.1 kg, was used for sound pressure level measurements. This study established a relationship between distance, altitude and sound pressure level, finding that the sound decays approximately in line with 6 dB(A) reduction for a doubling of distance. The effect of the orientation of the multi-rotor unmanned aircraft system was also investigated. It was determined that the sound profile does not vary significantly around the periphery of the multi-rotor unmanned aircraft system in the Propeller-Plane. However, when measured with the observer underneath the multi-rotor unmanned aircraft system, the sound pressure level was found to vary by as much as 10 dB(A), with the greatest sound pressure level at approximately 45° from horizontal. Finally, an acoustic array was used to measure key frequencies for the main sound sources: motors and Propellers. It was found that extraneous noise from the multi-rotor unmanned aircraft system frame vibration and mounting methods was also common. Despite relatively low levels of sound being measured (especially when compared with conventional aircraft and rotorcraft), the increasing numbers of unmanned aircraft systems in urban environments, close to humans and dwellings, suggests that increasing complaints are likely. Thus, further research was suggested, including expanding the range of multi-rotor unmanned aircraft system to be tested, introducing DGPS, improving the mounting for indoor testing, and psychoacoustic analysis of the sound
Reece A Clothier - One of the best experts on this subject based on the ideXlab platform.
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acoustic signature measurement of small multi rotor unmanned aircraft systems
International Journal of Micro Air Vehicles, 2017Co-Authors: N Kloet, Simon C Watkins, Reece A ClothierAbstract:This work describes the testing involved in generating an acoustic signature profile of a small multi-rotor unmanned aircraft system. A typical multi-rotor unmanned aircraft system, with a weight of approximately 2.1 kg, was used for sound pressure level measurements. This study established a relationship between distance, altitude and sound pressure level, finding that the sound decays approximately in line with 6 dB(A) reduction for a doubling of distance. The effect of the orientation of the multi-rotor unmanned aircraft system was also investigated. It was determined that the sound profile does not vary significantly around the periphery of the multi-rotor unmanned aircraft system in the Propeller-Plane. However, when measured with the observer underneath the multi-rotor unmanned aircraft system, the sound pressure level was found to vary by as much as 10 dB(A), with the greatest sound pressure level at approximately 45° from horizontal. Finally, an acoustic array was used to measure key frequencies f...
Yang Y. - One of the best experts on this subject based on the ideXlab platform.
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Numerical analysis of Propeller induced ground vortices by actuator disk model
2017Co-Authors: Yang Y., Veldhuis L.l.m., Eitelberg G.Abstract:Abstract: During the ground operation of aircraft, the interaction between the propulsor-induced flow field and the ground may lead to the generation of ground vortices. Utilizing numerical approaches, the source of vorticity entering ground vortices is investigated. The results show that the production of wall-parallel components of vorticity has a strong contribution from the wall-parallel components of the pressure gradient on the wall, which is generated by the action of the propulsor. This mechanism is a supplementation for the vorticity transported from the far-field boundary layer, which has been assumed the main vorticity source in a number of previous publications. Furthermore, the quantitative prediction of the occurrence of ground vortices is performed from the numerical results. As the distance of the Propeller form the ground decreases, and as the thrust of the Propeller increases, ground vortices are generated from the ground and enter the Propeller. In addition, the vortices which exist near the ground but does not enter the Propeller Plane are observed and visualized by three-dimensional data. Graphical abstract: [Figure not available: see fulltext.]
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Numerical analysis of Propeller induced ground vortices by actuator disk model
'Springer Science and Business Media LLC', 2017Co-Authors: Yang Y., Veldhuis L.l.m., Eitelberg G.Abstract:Abstract: During the ground operation of aircraft, the interaction between the propulsor-induced flow field and the ground may lead to the generation of ground vortices. Utilizing numerical approaches, the source of vorticity entering ground vortices is investigated. The results show that the production of wall-parallel components of vorticity has a strong contribution from the wall-parallel components of the pressure gradient on the wall, which is generated by the action of the propulsor. This mechanism is a supplementation for the vorticity transported from the far-field boundary layer, which has been assumed the main vorticity source in a number of previous publications. Furthermore, the quantitative prediction of the occurrence of ground vortices is performed from the numerical results. As the distance of the Propeller form the ground decreases, and as the thrust of the Propeller increases, ground vortices are generated from the ground and enter the Propeller. In addition, the vortices which exist near the ground but does not enter the Propeller Plane are observed and visualized by three-dimensional data. Graphical abstract: [Figure not available: see fulltext.]Flight Performance and Propulsio
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Propeller and inflow vortex interaction: vortex response and impact on the Propeller performance
'Springer Science and Business Media LLC', 2016Co-Authors: Yang Y., Veldhuis L.l.m., Zhou T, Sciacchitano A., Eitelberg G.Abstract:The aerodynamic operating conditions of a Propeller can include complex situations where vorticity from sources upstream can enter the Propeller Plane. In general, when the vorticity enters in a concentrated form of a vortex, the interaction between the vortex and blade is referred to as blade–vortex interaction or BVI. The interaction may affect the Propeller performance as well as its noise production. In the present paper, investigations of the interaction of a wing tip vortex generated by a lifting surface upstream of the rotor Plane and an eight-bladed Propeller are reported. Utilizing two ends of an upstream wing with non-symmetrical airfoil, the rotation of the incoming vortex could be made to co-rotate or to contra-rotate with the Propeller. The ensuing velocity fields were quantified with the help of particle image velocimetry (PIV), and the Propeller performance was evaluated with the help of a rotating shaft balance (RSB) mounted on the Propeller shaft. The results describe the displacement of the vortex core, as it moves through the rotor Plane as well as the positive effect on the thrust and torque of the contra-rotating vortex and the opposite of it in the case of the co-rotating vortex. The current research could be applied to analyse the influence of the incoming vortex on the Propeller, e.g., ground vortex, tip vortex shed from a control surface, etc.Flight Performance and PropulsionAerodynamic
