An analytical solution to the aeroelastic response of a two-dimensional elastic plate in axial potential flow

Medina, Cory; Kang, Chang-Kwon

doi:10.1017/jfm.2018.264

Cited by 6 publications

(9 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3 from the Euler-Bernoulli beam equation, where u c and l c denote the characteristic velocity and length of geometry, respectively (Shapiro 1977;Kang et al 2011;Dewey et al 2013;Siviglia & Toffolon 2014;Medina & Kang 2018). In those cases, the elastic body exchanges momentum with the fluid flow through the bending force (∼ Eh 3 /l c , if the magnitude of the beam deflection is comparable to the characteristic length) and the inertia of flow is scaled as ρ f u 2 t l 2 c .…”

Section: Measurement Of Flow Velocity and Nozzle Deformationmentioning

confidence: 99%

“…A brief scale analysis is given as follows. When the amplitude of nozzle deflection is δ b , the bending force can be scaled as Eh 3 δ b /l 2 c (Shapiro 1977;Kang et al 2011;Dewey et al 2013;Siviglia & Toffolon 2014;Medina & Kang 2018), whereas the tensile force is associated with Ehδ t , where δ t denotes the displacement of the axisymmetric expansion (Kraus 1967). If the nozzle is very thin (i.e.…”

Section: Change In the Jet Characteristics With Nozzle Stiffnessmentioning

confidence: 99%

“…As a method to control the hydrodynamics of a moving body, on the other hand, many nature-inspired researches have investigated the fluid-structure interaction in the flow over a flexible (compliant) surface (Triantafyllou, Triantafyllou & Grosenbaugh 1993;Kang et al 2011;Marais et al 2012;Park et al 2012Park et al , 2016Dewey et al 2013;Quinn, Lauder & Smits 2014, 2015David, Govardhan & Arakeri 2017;Medina & Kang 2018). In common, they reported that a certain level of flexibility enhances thrust generation or power efficiency of a flapping wing and fin model, which has been explained through the alignment of shed vortices with surface deformation.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Flow–structure interaction of a starting jet through a flexible circular nozzle

Choi

Park²

2022

J. Fluid Mech.

View full text Add to dashboard Cite

In the present study, the flow–structure interaction of a starting jet through a flexible nozzle is experimentally investigated, with a focus on the optimal flexibility for thrust generation. Water slug is impulsively accelerated through a cylindrical nozzle, fabricated with silicone rubber of varying flexibility. In general, the flexible nozzle modifies the vortical structure of the jet and augments the thrust of the starting jet. The measurement of nozzle surface deformation revealed that a back-and-forth wave propagation on the nozzle surface is responsible for the jet-vortex evolution augmenting the thrust generation. Combining the hydrodynamic conservation equations and the linearized shell theory, we also formulated the governing equations, dominated by two relevant dimensionless parameters: the effective acceleration time of the jet ( $\varPi _0$ ) and the effective nozzle stiffness ( $\varPi _1$ ). Asymptotic analysis of the equation showed that the dimensionless wave speed ( $\hat {c}$ ) is expressed as $\hat {c}=(\varPi _{0}^{2}\varPi _{1}/2)^{0.5}$ , and the jet momentum is maximized at $\hat {c}=\hat {c}_{crit}$ ( $\simeq 3.0$ ), the condition at which the release of elastic energy stored during nozzle contraction to the jet is synchronized with the instant of termination of jet acceleration. While $\hat {c}=\hat {c}_{crit}$ , the achievable maximum jet velocity decreases with the effective acceleration time of the jet ( $\varPi _0$ ), which is attributed to the reduced speed of the surface wave by the flow inside the nozzle.

show abstract

Section: Measurement Of Flow Velocity and Nozzle Deformationmentioning

confidence: 99%

Section: Change In the Jet Characteristics With Nozzle Stiffnessmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Flow–structure interaction of a starting jet through a flexible circular nozzle

Choi

Park²

2022

J. Fluid Mech.

View full text Add to dashboard Cite

show abstract

“…Two sheets of length L are immersed in a two-dimensional, incompressible uniform flow of air. The problem is reduced to a 2D problem, which is the same as most of the previous studies (Shelley and Zhang, 2011;Putri et al, 2014;Medina and Kang, 2018). The cost and time required for 3D analysis of this problem are unbearable.…”

Section: Establishment Of the Model 21 Background And Physical Model Establishmentmentioning

confidence: 99%

“…Researchers attempt to interpret and analyze these phenomena using theoretical analysis such as linear stability analysis and eigenvalue analysis Eloy et al, 2008;Shelley and Zhang, 2011;Shoele and Mittal, 2016;Medina and Kang, 2018). However, pure theoretical analysis cannot obtain a transient response, and it is difficult to perform nonlinear analysis, although these problems are nonlinear.…”

Section: Introductionmentioning

confidence: 99%

Modeling and simulation of sheets ply separation induced by air flow

Yang

2019

View full text Add to dashboard Cite

Purpose The purpose of this paper is to investigate the mechanism of sheets ply separation induced by air flow through numerical simulation with two-way FSI (fluid-structure interaction) simulation using ANSYS and theoretical speculation. Design/methodology/approach The paper primarily establishes a simplified physical model of the sheets ply separation induced by air flow. Then, the force of the air flow acting on the sheet has been analyzed based on the model, and the main factor leading to separation was obtained. Furthermore, the parameter analysis was investigated based on linear stability analysis, from which the factors that affect stable separation are obtained. Finally, a series of numerical simulations are performed to verify the conclusions. Findings This study shows that the main separation factor is the variable air pressure in the gap between the sheets caused by the dynamic pressure air flow. Increasing the inlet velocity of the flow field will increase the separation distance but excessive velocity will lead to instability. The viscous resistance acting on the sheet and the bending stiffness of the sheet are factors that stabilize the system, and the sheet density and the restoring force can lead to instability. Originality/value The paper is one of the first in the literature that investigates the problem of sheets ply separation induced by air flow, which is the primary method for multi-layer separation in sheets de-stacking operations, especially for the high-speed occasion.

show abstract

Analysis of passive flexion in propelling a plunging plate using a torsion spring model

et al. 2018

View full text Add to dashboard Cite

We mimic a flapping wing through a fluid–structure interaction (FSI) framework based upon a generalized lumped-torsional flexibility model. The developed fluid and structural solvers together determine the aerodynamic forces, wing deformation and self-propelled motion. A phenomenological solution to the linear single-spring structural dynamics equation is established to help offer insight and validate the computations under the limit of small deformation. The cruising velocity and power requirements are evaluated by varying the flapping Reynolds number ($20\leqslant Re_{f}\leqslant 100$), stiffness (represented by frequency ratio,$1\lesssim \unicode[STIX]{x1D714}^{\ast }\leqslant 10$) and the ratio of aerodynamic to structural inertia forces (represented by a dimensionless parameter$\unicode[STIX]{x1D713}$($0.1\leqslant \unicode[STIX]{x1D713}\leqslant 3$)). For structural inertia dominated flows ($\unicode[STIX]{x1D713}\ll 1$), pitching and plunging are shown to always remain in phase ($\unicode[STIX]{x1D719}\approx 0$) with the maximum wing deformation occurring at the end of the stroke. When aerodynamics dominates ($\unicode[STIX]{x1D713}>1$), a large phase difference is induced ($\unicode[STIX]{x1D719}\approx \unicode[STIX]{x03C0}/2$) and the maximum deformation occurs at mid-stroke. Lattice Boltzmann simulations show that there is an optimal$\unicode[STIX]{x1D714}^{\ast }$at which cruising velocity is maximized and the location of optimum shifts away from unit frequency ratio ($\unicode[STIX]{x1D714}^{\ast }=1$) as$\unicode[STIX]{x1D713}$increases. Furthermore, aerodynamics administered deformations exhibit better performance than those governed by structural inertia, quantified in terms of distance travelled per unit work input. Closer examination reveals that although maximum thrust transpires at unit frequency ratio, it is not transformed into the highest cruising velocity. Rather, the maximum velocity occurs at the condition when the relative tip displacement${\approx}\,0.3$.

show abstract

An analytical solution to the aeroelastic response of a two-dimensional elastic plate in axial potential flow

Cited by 6 publications

References 12 publications

Flow–structure interaction of a starting jet through a flexible circular nozzle

Flow–structure interaction of a starting jet through a flexible circular nozzle

Modeling and simulation of sheets ply separation induced by air flow

Analysis of passive flexion in propelling a plunging plate using a torsion spring model

Contact Info

Product

Resources

About