Reynolds number, thickness and camber effects on flapping airfoil propulsion

Ashraf, Muhammad A; Young, John; Lai, J.C.S.

doi:10.1016/j.jfluidstructs.2010.11.010

Cited by 147 publications

(84 citation statements)

References 34 publications

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“…The far-field boundary was set to at least 30c from the airfoil such that its effect on the flow around the moving airfoil was negligible (Bos et al, 2008). The inner zone employed a moving mesh for pitching motion whereas the outer zone was fixed, as employed by Wang et al (2010) and Ashraf et al (2011). The dynamic mesh motion was controlled by a CFX expression language (CEL) subroutine developed and attached to the CFX solver.…”

Section: Solvermentioning

confidence: 99%

“…This thrust producing phenomenon associated with oscillating airfoil motion is called Katzmyer effect according to Jones and Platzer (1998), Lewin and Haj-Hariri (2003). Extensive computational work related to oscillating foils can be found in Tuncer and Platzer (1995), Tuncer et al (1998), Isogai et al (1999), Ramamurti and Sandberg (2001), Young and Lai (2004, 2007a, 2007b, Platzer et al (2008) and Ashraf et al (2011). Several numerical analysis methods such as unsteady potential flow, Navier-Stokes (NS) computations and vortex method have been employed.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical study of large amplitude, nonsinusoidal motion and camber effects on pitching airfoil propulsion

Xie

Zhang

2013

Journal of Fluids and Structures

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Section: Solvermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical study of large amplitude, nonsinusoidal motion and camber effects on pitching airfoil propulsion

Xie

Zhang

2013

Journal of Fluids and Structures

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“…With the introduction of non-zero angle of attack, the airfoil may generate both thrust and lift. Heaving and pitching airfoils have also been studied extensively [Anderson et al, 1998, Ramamurti and Sandberg, 2001, Read et al, 2003, Ashraf et al, 2011, Baik et al, 2012, Widmann and Tropea, 2015. Pitching modifies the flow around the airfoil and can, for some combinations of the motion parameters, increase the net value of thrust and the propulsive efficiency.…”

Section: Introductionmentioning

confidence: 99%

On the aerodynamic forces on heaving and pitching airfoils at low Reynolds number

2017

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The influence that the kinematics of pitching and heaving 2D airfoils have on the aerodynamic forces is investigated using Direct Numerical Simulations and a force decomposition algorithm. Large amplitude motions are considered (of the order of one chord), with moderate Reynolds numbers and reduced frequencies of order O(1), varying the mean pitch angle and the phase shift between the pitching and heaving motions. Our results show that the surface vorticity contribution (viscous effects) to the aerodynamic force is negligible compared to the contributions from the body motion (fluid inertia) and the vorticity within the flow (circulation). For the range of parameters considered here, the latter tends to be instantaneously oriented in the direction normal to the chord of the airfoil. Based on the results discussed in the paper, a reduced order model for the instantaneous aerodynamic force is proposed, taking advantage of the force decomposition and the chord-normal orientation of the contribution from vorticity within the flow to the total aerodynamic force. The predictions of the proposed model are compared to those of a similar model from the literature, showing a noticeable improvement on the prediction of the mean thrust, and a smaller improvement on the prediction of mean lift and the instantaneous force coefficients.

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“…Simulating the complicated multidisciplinary physics associated with flapping flights is often attempted with highfidelity numerical models based on solving Navier-Stokes (Ashraf et al, 2011;Benkherouf et al, 2011;Liu, 2009;Martinat et al, 2008;Vanella et al, 2009;Yuan et al, 2010). These high-fidelity models require mesh generation of the entire fluid domain and robust numerical schemes to handle the linear and nonlinear terms of the fluid governing equations.…”

Section: Introductionmentioning

confidence: 99%