Effectiveness of Side Force Models for Flow Simulations Downstream of Vortex Generators

Florentie, Liesbeth; Zuijlen, A.H. van; Hulshoff, Steven J.; Bijl, H.

doi:10.2514/1.j055268

Cited by 10 publications

(3 citation statements)

References 24 publications

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“…The latter approach allows for a vortex to be studied in application without the computational cost of modelling a MVG directly while the former approach allows for a more realistic appraisal of a MVG has on the flow. Florentie et al [16] found the BAY and jBAY models to be very dependent on the mesh resolution and resolving the VG vane lead to better results when compared to experimental results.…”

Section: Iintroductionmentioning

confidence: 99%

Numerical and Experimental Study of Microvortex Generators

Heffron

Williams

Avital

2018

Journal of Aircraft

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A series of experimental and computational studies was conducted on vane-type microvortex generators (MVG) with the aim of better understanding the behaviour and to improve the design of such devices. The traditional rectangular and triangular vanes along with unique NACA0012 and E423 airfoils shaped vanes were studied with a height of 0.2δ while being embedded in a turbulent boundary layer of a flat plate. To assess the reliability of the numerical prediction of the drag forces acting on a MVG, a wind tunnel experiment was conducted. The experiment was conducted at a Reynolds number of 155, based on the friction velocity and the MVG height. A very good agreement was found between the experimental and numerical drag predictions for the MVGs with strong vortices. Fair agreement was found for the two MVGs with weak vortices. From the four-specified vane-type MVGs, the best performing MVG configuration was sought by looking at the ratio of the vortex's circulation strength to the drag of the MVG vanes. It was found that triangular vanes had the best ratio and NACA0012 shaped vanes had the second best ratio. With altercation of the vane angle, vanes placed at angles of 18˚ to 20˚ had the best ratio. To supplement the performance study, the effect of the Reynolds number on the MVGs was also considered. A rectangular MVG vane was modelled at Reynolds numbers of 90 to 1150. A logarithmic relation was found between the Reynolds number of the MVG and the generated vortex's circulation and the drag of the MVG.

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Section: Iintroductionmentioning

confidence: 99%

Numerical and Experimental Study of Microvortex Generators

Heffron

Williams

Avital

2018

Journal of Aircraft

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“…The BAY model was originally proposed by Bender et al (1999) and was originally used to predict secondary flows behind inclined thin-plate VGs. This approach uses the lifting-force theory on thin-plate airfoil (Baldacchino et al , 2016; Booker et al , 2009; Florentie et al , 2017; Manolesos et al , 2014; Sznajder and Kwiatkowski, 2015). Kwiatkowski and Flaszyński (2016a, 2016b) demonstrated that this approach, after some modifications, may be used to predict flows behind RVGs.…”

Section: New Bay Model Of Rod Vortex Generatorsmentioning

confidence: 99%

Source term model for rod vortex generator

Kwiatkowski

Flaszyński

Żółtak

2019

AEAT

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Purpose The simulations of grid-resolved rod vortex generators (RVGs) require high computational cost and time. Additionally, the computational mesh topology must be adjusted to rods geometries. The purpose of this study is to propose the new source term model for RVG. Design/methodology/approach The model was proposed by modification of Bender, Anderson, Yagle (BAY) model used to predict flows around different type of vortex generators (VGs) – vanes. Original BAY model was built on lifting line theory. The proposed model was implemented in ANSYS Fluent by means of the user-defined function technique. Additional momentum and energy sources are imposed to transport equations. Findings The computational results of source term model were validated against experimental data and numerical simulation results for grid-resolved rod. It was shown that modified BAY model can be successfully used for RVG in complex cases. An example of BAY model application for RVG on transonic V2C airfoil with strongly oscillating shock waves is presented. Aerodynamic performance predicted numerically by means of both approaches (grid resolved RVG and modeled) is in good agreement, what indicates application opportunity of the proposed model to complex cases. Practical implications Modified BAY model can be used to simulate the influence of RVGs in complex real cases. It allows for time/cost reduction if the location or distribution of RVG has to be optimized on a profile, wing or in the channel. Originality/value In the paper, the new modification of BAY model was proposed to simulate RVGs. The presented results are innovative because of original approach to model RVGs.

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“…Prior research on modeling VGs in CFD methods can be found in references, e.g. [6] and [7]. However, the above mentioned modeling methods require an expensive CFD simulations.…”

Section: Introductionmentioning

confidence: 99%

Towards a Vortex Generator Model for Integral Boundary Layer Methods

Ravishanara

Özdemir²,

Franco

2019

AIAA Scitech 2019 Forum

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In this study a new approach to model the effect of vortex generators in integral boundary layer equations is described. Vortex generators (VGs) are commonly used on wind turbine blades to avoid early separation of flow which helps not only to increase the lift but also delays the stall. Delaying the stall angle of wind turbine blades will allow for operation over larger range of angle of attacks and thus increase power production from wind turbines. Typically, VGs are submerged in the boundary layer and generate vortices that mix high-energy fluid from outer flow with the slow-moving boundary layer. Within this study the effect of the VGs on the 2-D boundary layers are modeled as additional mixing. The presence of a new shear layer will lead to additional viscous dissipation and affect the wall shear stress. To model these effects new terms are introduced into the integral boundary layer equations to account for the extra mass and momentum flux and turbulence production. The additional unknowns introduced into the system of equations are derived using CFD simulations. Initial CFD simulations on a flat plate with body fitted meshes around VGs are used to obtain an algebraic model. The new model is implemented in an aerodynamic analysis and design tool and preliminary results are presented. The theory developed here will be extended for flows over airfoils.

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Effectiveness of Side Force Models for Flow Simulations Downstream of Vortex Generators

Cited by 10 publications

References 24 publications

Numerical and Experimental Study of Microvortex Generators

Numerical and Experimental Study of Microvortex Generators

Source term model for rod vortex generator

Towards a Vortex Generator Model for Integral Boundary Layer Methods

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