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Haibo Dong - One of the best experts on this subject based on the ideXlab platform.
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computational investigation of wing body interaction and its lift enhancement effect in hummingbird Forward Flight
Bioinspiration & Biomimetics, 2019Co-Authors: Junshi Wang, Yan Ren, Haibo DongAbstract:A lift enhancement mechanism due to wing-body interaction (WBI) was previously proved to be significant in the Forward Flight of insect flyers with wide-shape bodies, such as cicada. In order to further explore WBI and its lift enhancement effect in a flapping Flight platform with different wing and body shapes, numerical investigations of WBI were performed on the Forward Flight of a hummingbird in this paper. A high-fidelity computational model of a hummingbird in Forward Flight was modeled with its geometric complexity. The wing kinematics of flapping Flight were prescribed using experimental data from previous literature. An immersed-boundary-method-based incompressible Navier‒Stokes solver was used for the 3D flow simulations of the wing-body system. Analyses on aerodynamic performances and vortex dynamics of three models, including the wing-body (WB), wing-only (WO), and body-only (BO) models, were made to examine the effect of WBI. Results have shown significant overall lift enhancement (OLE) due to WBI. The total lift force of the WB model increased by 29% compared with its WO/BO counterparts. Vortex dynamics results showed formations of unique body vortex pairs on the dorsal thorax of hummingbird where low-pressure zones were created to generate more body lift. Significant interactions between body vortex and leading-edge vortex (LEV) were observed, resulting in strengthened LEVs near the wing root and enhanced wing lift generation during downstroke. Parametric studies showed strong OLEs over wide ranges of body angle and advance ratio, respectively. The contribution of OLE from the hummingbird body increased with increasing body angle, and the wing pair's contribution increased as advance ratio increased. Results from this paper supported that lift enhancement due to WBI is potentially a general mechanism adopted by different kinds of flapping-wing flyers, and demonstrated the potential of WBI in the design of flapping-wing micro aerial vehicle (MAV) that pursue higher performance.
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vortex dynamics and new lift enhancement mechanism of wing body interaction in insect Forward Flight
Journal of Fluid Mechanics, 2016Co-Authors: Geng Liu, Haibo DongAbstract:The effects of wing–body interaction (WBI) on aerodynamic performance and vortex dynamics have been numerically investigated in the Forward Flight of cicadas. Flapping wing kinematics was reconstructed based on the output of a high-speed camera system. Following the reconstruction of cicada Flight, three models, wing–body (WB), body-only (BD) and wings-only (WN), were then developed and evaluated using an immersed-boundary-method-based incompressible Navier–Stokes equations solver. Results have shown that due to WBIs, the WB model had a 18.7 % increase in total lift production compared with the lift generated in both the BD and WN models, and about 65 % of this enhancement was attributed to the body. This resulted from a dramatic improvement of body lift production from 2 % to 11.6 % of the total lift produced by the wing–body system. Further analysis of the associated near-field and far-field vortex structures has shown that this lift enhancement was attributed to the formation of two distinct vortices shed from the thorax and the posterior of the insect, respectively, and their interactions with the flapping wings. Simulations are also used to examine the new lift enhancement mechanism over a range of minimum wing–body distances, reduced frequencies and body inclination angles. This work provides a new physical insight into the understanding of the body-involved lift-enhancement mechanism in insect Forward Flight.
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computational investigation of cicada aerodynamics in Forward Flight
Journal of the Royal Society Interface, 2015Co-Authors: Hui Wan, Haibo Dong, Kuo GaiAbstract:Free Forward Flight of cicadas is investigated through high-speed photogrammetry, three-dimensional surface reconstruction and computational fluid dynamics simulations. We report two new vortices generated by the cicada's wide body. One is the thorax-generated vortex, which helps the downwash flow, indicating a new phenomenon of lift enhancement. Another is the cicada posterior body vortex, which entangles with the vortex ring composed of wing tip, trailing edge and wing root vortices. Some other vortex features include: independently developed left- and right-hand side leading edge vortex (LEV), dual-core LEV structure at the mid-wing region and near-wake two-vortex-ring structure. In the cicada Forward Flight, approximately 79% of the total lift is generated during the downstroke. Cicada wings experience drag in the downstroke, and generate thrust during the upstroke. Energetics study shows that the cicada in free Forward Flight consumes much more power in the downstroke than in the upstroke, to provide enough lift to support the weight and to overcome drag to move Forward.
Mao Sun - One of the best experts on this subject based on the ideXlab platform.
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lateral dynamic Flight stability of a model bumblebee in hovering and Forward Flight
Journal of Theoretical Biology, 2013Co-Authors: Mao SunAbstract:Abstract The lateral dynamic Flight stability of a model bumblebee in hovering and Forward Flight is studied, using the method of computational fluid dynamics to compute the stability derivatives and the techniques of eigenvalue and eigenvector analysis for solving the equations of motion. The lateral motion of the model bumblebee is unstable at hovering and low Flight speed (advance ratio J=0, 0.13), and becomes neutral or weakly stable at medium and high Flight speeds (J=0.31–0.57). The instability at hovering and low speed is mainly caused by a positive roll-moment derivative with respect to the side-slip velocity, which is due to the effect of changing the axial velocity of the leading-edge-vortex (LEV) (i.e. the ‘lateral wind’ due to the side motion of the insect increases the axial velocity of the LEV on one wing and decreases that on the other wing). As Flight speed increases, because the mean position of the wings moves more and more backward, the effect of ‘changing-LEV-axial-velocity’ becomes weaker and weaker and the roll-moment derivative decreases first and then changes its sign to become negative, resulting in the neutrally or weakly stable motion at medium and high Flight speeds.
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aerodynamic interactions between wing and body of a model insect in Forward Flight and maneuvers
Journal of Bionic Engineering, 2013Co-Authors: Bin Liang, Mao SunAbstract:The aerodynamic interactions between the body and the wings of a model insect in Forward Flight and maneuvers are studied using the method of numerically solving the Navier-Stokes equations over moving overset grids. Three cases are considered, including a complete insect, wing pair only and body only. By comparing the results of these cases, the interaction effect between the body and the wing pair can be identified. The changes in the force and moment coefficients of the wing pair due to the presence of the body are less than 4.5% of the mean vertical force coefficient of the model insect; the changes in the aerodynamic force coefficients of the body due to the presence of the wings are less than 5.0% of the mean vertical force coefficient of the model insect. The results of this paper indicate that in studying the aerodynamics and Flight dynamics of a flapping insect in Forward Flight or maneuver, separately computing (or measuring) the aerodynamic forces and moments on the wing pair and on the body could be a good approximation.
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aerodynamic effects of corrugation in flapping insect wings in Forward Flight
Journal of Bionic Engineering, 2011Co-Authors: Xueguang Meng, Mao SunAbstract:We have examined the aerodynamic effects of corrugation in model wings that closely mimic the wing movements of a Forward Flight bumblebee using the method of computational fluid dynamics. Various corrugated wing models were tested (care was taken to ensure that the corrugation introduced zero camber). Advance ratio ranging from 0 to 0.57 was considered. The results shown that at all Flight speeds considered, the time courses of aerodynamic force of the corrugated wing are very close to those of the flat-plate wing. The corrugation decreases aerodynamic force slightly. The changes in the mean location of center of pressure in the spanwise and chordwise directions resulting from the corrugation are no more than 3% of the wing chord length. The possible reason for the small aerodynamic effects of wing corrugation is that the wing operates at a large angle of attack and the flow is separated: the large angle of incidence dominates the corrugation in determining the flow around the wing, and for separated flow, the flow is much less sensitive to wing shape variation.
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dynamic Flight stability of a bumblebee in Forward Flight
Acta Mechanica Sinica, 2008Co-Authors: Yan Xiong, Mao SunAbstract:The longitudinal dynamic Flight stability of a bumblebee in Forward Flight is studied. The method of computational fluid dynamics is used to compute the aerodynamic derivatives and the techniques of eigenvalue and eigenvector analysis are employed for solving the equations of motion. The primary findings are as the following. The Forward Flight of the bumblebee is not dynamically stable due to the existence of one (or two) unstable or approximately neutrally stable natural modes of motion. At hovering to medium Flight speed [Flight speed u e = (0–3.5) m s−1; advance ratio J = 0–0.44], the Flight is weakly unstable or approximately neutrally stable; at high speed (u e = 4.5 m s−1; J = 0.57), the Flight becomes strongly unstable (initial disturbance double its value in only 3.5 wingbeats).
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aerodynamic force generation and power requirements in Forward Flight in a fruit fly with modeled wing motion
The Journal of Experimental Biology, 2003Co-Authors: Mao SunAbstract:Aerodynamic force generation and power requirements in Forward Flight in a fruit fly with modeled wing motion were studied using the method of computational fluid dynamics. The Navier-Stokes equations were solved numerically. The solution provided the flow velocity and pressure fields, from which the vorticity wake structure and the unsteady aerodynamic forces and torques were obtained (the inertial torques due to the acceleration of the wing-mass were computed analytically). From the flow-structure and force information, insights were gained into the unsteady aerodynamic force generation. On the basis of the aerodynamic and inertial torques, the mechanical power was obtained, and its properties were investigated. The unsteady force mechanisms revealed previously for hovering (i.e. delayed stall, rapid acceleration at the beginning of the strokes and fast pitching-up rotation at the end of the strokes) apply to Forward Flight. Even at high advance ratios, e.g. J=0.53-0.66 (J is the advance ratio), the leading edge vortex does not shed (at such advance ratios, the wing travels approximately 6.5 chord lengths during the downstroke). At low speeds (J approximately equal to 0.13), the lift (vertical force) for weight support is produced during both the down- and upstrokes (the downstroke producing approximately 80% and the upstroke producing approximately 20% of the mean lift), and the lift is contributed mainly by the wing lift; the thrust that overcomes the body drag is produced during the upstroke, and it is contributed mainly by the wing drag. At medium speeds (J approximately equal to 0.27), the lift is mainly produced during the downstroke and the thrust mainly during the upstroke; both of them are contributed almost equally by the wing lift and wing drag. At high speeds (J approximately equal to 0.53), the lift is mainly produced during the downstroke and is mainly contributed by the wing drag; the thrust is produced during both the down- and upstrokes, and in the downstroke, is contributed by the wing lift and in the upstroke, by the wing drag. In Forward Flight, especially at medium and high Flight speeds, the work done during the downstroke is significantly greater than during the upstroke. At advance ratios J approximately equal to 0.13, 0.27 and 0.53, the work done during the downstroke is approximately 1.6, 2.8 and 4.2 times as much as that during the upstroke, respectively. At J=0 (hovering), the body-mass-specific power is approximately 29 W kg(-1); at J=0.13 and 0.27, the power is approximately 10% less than that of hovering; at J=0.40, the power is approximately the same as that of hovering; when J is further increased, the power increases sharply. The graph of power against flying speeds is approximately J-shaped. From the graph of power against flying speeds, it is predicted that the insect usually flies at advance ratios between zero and 0.4, and for fast Flight, it would fly at an advance ratio between 0.4 and 0.53.
Doyoung Byun - One of the best experts on this subject based on the ideXlab platform.
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How Could Beetle’s Elytra Support Their Own Weight during Forward Flight?
Journal of Bionic Engineering, 2014Co-Authors: Tien Van Truong, Soo Hyung Park, Hieu Trung Tran, Hoon Cheol Park, Doyoung ByunAbstract:The aerodynamic role of the elytra during a beetle’s flapping motion is not well-elucidated, although it is well-recognized that the evolution of elytra has been a key in the success of coleopteran insects due to their protective function. An experimental study on wing kinematics reveals that for almost concurrent flapping with the hind wings, the flapping angle of the elytra is 5 times smaller than that of the hind wings. Then, we explore the aerodynamic forces on elytra in free Forward Flight with and without an effect of elytron-hind wing interaction by three-dimensional numerical simulation. The numerical results show that vertical force generated by the elytra without interaction is not sufficient to support even its own weight. However, the elytron-hind wing interaction improves the vertical force on the elytra up to 80%; thus, the total vertical force could fully support its own weight. The interaction slightly increases the vertical force on the hind wind by 6% as well.
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how could beetle s elytra support their own weight during Forward Flight
Journal of Bionic Engineering, 2014Co-Authors: Soo Hyung Park, Hieu Trung Tran, Hoon Cheol Park, Tien Van Truong, Doyoung ByunAbstract:Abstract The aerodynamic role of the elytra during a beetle's flapping motion is not well-elucidated, although it is well-recognized that the evolution of elytra has been a key in the success of coleopteran insects due to their protective function. An experimental study on wing kinematics reveals that for almost concurrent flapping with the hind wings, the flapping angle of the elytra is 5 times smaller than that of the hind wings. Then, we explore the aerodynamic forces on elytra in free Forward Flight with and without an effect of elytron-hind wing interaction by three-dimensional numerical simulation. The numerical results show that vertical force generated by the elytra without interaction is not sufficient to support even its own weight. However, the elytron-hind wing interaction improves the vertical force on the elytra up to 80%; thus, the total vertical force could fully support its own weight. The interaction slightly increases the vertical force on the hind wind by 6% as well.
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improvement of the aerodynamic performance by wing flexibility and elytra hind wing interaction of a beetle during Forward Flight
Journal of the Royal Society Interface, 2013Co-Authors: Tien Van Truong, Soo Hyung Park, Hoon Cheol Park, Tri Quang Truong, Doyoung ByunAbstract:In this work, the aerodynamic performance of beetle wing in free-Forward Flight was explored by a three-dimensional computational fluid dynamics (CFDs) simulation with measured wing kinematics. It is shown from the CFD results that twist and camber variation, which represent the wing flexibility, are most important when determining the aerodynamic performance. Twisting wing significantly increased the mean lift and camber variation enhanced the mean thrust while the required power was lower than the case when neither was considered. Thus, in a comparison of the power economy among rigid, twisting and flexible models, the flexible model showed the best performance. When the positive effect of wing interaction was added to that of wing flexibility, we found that the elytron created enough lift to support its weight, and the total lift (48.4 mN) generated from the simulation exceeded the gravity force of the beetle (47.5 mN) during Forward Flight.
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two and three dimensional simulations of beetle hind wing flapping during free Forward Flight
Journal of Bionic Engineering, 2013Co-Authors: Tien Van Truong, Soo Hyung Park, Hieu Trung Tran, Hoon Cheol Park, Kwang Joon Yoon, Doyoung ByunAbstract:Abstract Aerodynamic characteristic of the beetle, Trypoxylus dichotomus, which has a pair of elytra (forewings) and hind wings, is numerically investigated. Based on the experimental results of wing kinematics, two-dimensional (2D) and three-dimensional (3D) computational fluid dynamic simulations were carried out to reveal aerodynamic performance of the hind wing. The roles of the spiral Leading Edge Vortex (LEV) and the spanwise flow were clarified by comparing 2D and 3D simulations. Mainly due to pitching down of chord line during downstroke in highly inclined stroke plane, relatively high averaged thrust was produced in the free Forward Flight of the beetle. The effects of the local corrugation and the camber variation were also investigated for the beetle's hind wings. Our results show that the camber variation plays a significant role in improving both lift and thrust in the flapping. On the other hand, the local corrugation pattern has no significant effect on the aerodynamic force due to large angle of attack during flapping.
Soo Hyung Park - One of the best experts on this subject based on the ideXlab platform.
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How Could Beetle’s Elytra Support Their Own Weight during Forward Flight?
Journal of Bionic Engineering, 2014Co-Authors: Tien Van Truong, Soo Hyung Park, Hieu Trung Tran, Hoon Cheol Park, Doyoung ByunAbstract:The aerodynamic role of the elytra during a beetle’s flapping motion is not well-elucidated, although it is well-recognized that the evolution of elytra has been a key in the success of coleopteran insects due to their protective function. An experimental study on wing kinematics reveals that for almost concurrent flapping with the hind wings, the flapping angle of the elytra is 5 times smaller than that of the hind wings. Then, we explore the aerodynamic forces on elytra in free Forward Flight with and without an effect of elytron-hind wing interaction by three-dimensional numerical simulation. The numerical results show that vertical force generated by the elytra without interaction is not sufficient to support even its own weight. However, the elytron-hind wing interaction improves the vertical force on the elytra up to 80%; thus, the total vertical force could fully support its own weight. The interaction slightly increases the vertical force on the hind wind by 6% as well.
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how could beetle s elytra support their own weight during Forward Flight
Journal of Bionic Engineering, 2014Co-Authors: Soo Hyung Park, Hieu Trung Tran, Hoon Cheol Park, Tien Van Truong, Doyoung ByunAbstract:Abstract The aerodynamic role of the elytra during a beetle's flapping motion is not well-elucidated, although it is well-recognized that the evolution of elytra has been a key in the success of coleopteran insects due to their protective function. An experimental study on wing kinematics reveals that for almost concurrent flapping with the hind wings, the flapping angle of the elytra is 5 times smaller than that of the hind wings. Then, we explore the aerodynamic forces on elytra in free Forward Flight with and without an effect of elytron-hind wing interaction by three-dimensional numerical simulation. The numerical results show that vertical force generated by the elytra without interaction is not sufficient to support even its own weight. However, the elytron-hind wing interaction improves the vertical force on the elytra up to 80%; thus, the total vertical force could fully support its own weight. The interaction slightly increases the vertical force on the hind wind by 6% as well.
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improvement of the aerodynamic performance by wing flexibility and elytra hind wing interaction of a beetle during Forward Flight
Journal of the Royal Society Interface, 2013Co-Authors: Tien Van Truong, Soo Hyung Park, Hoon Cheol Park, Tri Quang Truong, Doyoung ByunAbstract:In this work, the aerodynamic performance of beetle wing in free-Forward Flight was explored by a three-dimensional computational fluid dynamics (CFDs) simulation with measured wing kinematics. It is shown from the CFD results that twist and camber variation, which represent the wing flexibility, are most important when determining the aerodynamic performance. Twisting wing significantly increased the mean lift and camber variation enhanced the mean thrust while the required power was lower than the case when neither was considered. Thus, in a comparison of the power economy among rigid, twisting and flexible models, the flexible model showed the best performance. When the positive effect of wing interaction was added to that of wing flexibility, we found that the elytron created enough lift to support its weight, and the total lift (48.4 mN) generated from the simulation exceeded the gravity force of the beetle (47.5 mN) during Forward Flight.
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two and three dimensional simulations of beetle hind wing flapping during free Forward Flight
Journal of Bionic Engineering, 2013Co-Authors: Tien Van Truong, Soo Hyung Park, Hieu Trung Tran, Hoon Cheol Park, Kwang Joon Yoon, Doyoung ByunAbstract:Abstract Aerodynamic characteristic of the beetle, Trypoxylus dichotomus, which has a pair of elytra (forewings) and hind wings, is numerically investigated. Based on the experimental results of wing kinematics, two-dimensional (2D) and three-dimensional (3D) computational fluid dynamic simulations were carried out to reveal aerodynamic performance of the hind wing. The roles of the spiral Leading Edge Vortex (LEV) and the spanwise flow were clarified by comparing 2D and 3D simulations. Mainly due to pitching down of chord line during downstroke in highly inclined stroke plane, relatively high averaged thrust was produced in the free Forward Flight of the beetle. The effects of the local corrugation and the camber variation were also investigated for the beetle's hind wings. Our results show that the camber variation plays a significant role in improving both lift and thrust in the flapping. On the other hand, the local corrugation pattern has no significant effect on the aerodynamic force due to large angle of attack during flapping.
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euler and navier stokes simulations of helicopter rotor blade in Forward Flight using an overlapped grid solver
19th AIAA Computational Fluid Dynamics, 2009Co-Authors: Soo Hyung Park, Yung Hoon YuAbstract:Three-dimensional Euler and Navier-Stokes equations are solved using an overlapped grid system to compute the unsteady flow field around helicopter rotor blade in Forward Flight. To verify the automated overlapped grid solver, the unsteady flow field and airloads on Caradonna-Tung NACA0012 and AH-1G rotor blade models in Forward Flight were computed. Two equation turbulence model k-ω Wilcox Durbin(WD+) is used. For spatial discretization Roe FDS(Flux Difference Splitting) scheme and Weighted ENO(Essentially Non-Oscillatory) scheme are applied. Good agreement between computed and measured surface pressure distributions was seen for the Caradonna and Tung rotor’s Forward Flight simulation. The effects of background wake grid spacing, spatial accuracy and viscosity were examined in the AH-1G rotor simulation. Surface pressure distributions, sectional thrust and oscillatory pitching moment coefficients were compared with Flight test data. A better variation for sectional thrust and oscillatory pitching moment were found by using the Navier-Stokes analysis.
Tien Van Truong - One of the best experts on this subject based on the ideXlab platform.
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how could beetle s elytra support their own weight during Forward Flight
Journal of Bionic Engineering, 2014Co-Authors: Soo Hyung Park, Hieu Trung Tran, Hoon Cheol Park, Tien Van Truong, Doyoung ByunAbstract:Abstract The aerodynamic role of the elytra during a beetle's flapping motion is not well-elucidated, although it is well-recognized that the evolution of elytra has been a key in the success of coleopteran insects due to their protective function. An experimental study on wing kinematics reveals that for almost concurrent flapping with the hind wings, the flapping angle of the elytra is 5 times smaller than that of the hind wings. Then, we explore the aerodynamic forces on elytra in free Forward Flight with and without an effect of elytron-hind wing interaction by three-dimensional numerical simulation. The numerical results show that vertical force generated by the elytra without interaction is not sufficient to support even its own weight. However, the elytron-hind wing interaction improves the vertical force on the elytra up to 80%; thus, the total vertical force could fully support its own weight. The interaction slightly increases the vertical force on the hind wind by 6% as well.
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improvement of the aerodynamic performance by wing flexibility and elytra hind wing interaction of a beetle during Forward Flight
Journal of the Royal Society Interface, 2013Co-Authors: Tien Van Truong, Soo Hyung Park, Hoon Cheol Park, Tri Quang Truong, Doyoung ByunAbstract:In this work, the aerodynamic performance of beetle wing in free-Forward Flight was explored by a three-dimensional computational fluid dynamics (CFDs) simulation with measured wing kinematics. It is shown from the CFD results that twist and camber variation, which represent the wing flexibility, are most important when determining the aerodynamic performance. Twisting wing significantly increased the mean lift and camber variation enhanced the mean thrust while the required power was lower than the case when neither was considered. Thus, in a comparison of the power economy among rigid, twisting and flexible models, the flexible model showed the best performance. When the positive effect of wing interaction was added to that of wing flexibility, we found that the elytron created enough lift to support its weight, and the total lift (48.4 mN) generated from the simulation exceeded the gravity force of the beetle (47.5 mN) during Forward Flight.
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two and three dimensional simulations of beetle hind wing flapping during free Forward Flight
Journal of Bionic Engineering, 2013Co-Authors: Tien Van Truong, Soo Hyung Park, Hieu Trung Tran, Hoon Cheol Park, Kwang Joon Yoon, Doyoung ByunAbstract:Abstract Aerodynamic characteristic of the beetle, Trypoxylus dichotomus, which has a pair of elytra (forewings) and hind wings, is numerically investigated. Based on the experimental results of wing kinematics, two-dimensional (2D) and three-dimensional (3D) computational fluid dynamic simulations were carried out to reveal aerodynamic performance of the hind wing. The roles of the spiral Leading Edge Vortex (LEV) and the spanwise flow were clarified by comparing 2D and 3D simulations. Mainly due to pitching down of chord line during downstroke in highly inclined stroke plane, relatively high averaged thrust was produced in the free Forward Flight of the beetle. The effects of the local corrugation and the camber variation were also investigated for the beetle's hind wings. Our results show that the camber variation plays a significant role in improving both lift and thrust in the flapping. On the other hand, the local corrugation pattern has no significant effect on the aerodynamic force due to large angle of attack during flapping.