Rotor Wake Modeling with a Coupled Eulerian and Vortex Particle Method

Stone, Christopher; Duque, Earl P. N.; Hennes, Christopher C.; Gharakhani, Adrin

doi:10.2514/6.2010-312

Cited by 11 publications

(9 citation statements)

References 12 publications

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“…Flow states at locations 1 and 2 are already available. The state at location a is obtained from the points (9,12,14). There will always be such a sequence of points involving centroid, 12, and two of its neighbors with whom it shares a common vertex.…”

Section: E Implementation Of Viscous Termsmentioning

confidence: 99%

“…Thus, while highly capable adaptive grid Unsteady Reynolds-Averaged Navier-Stokes (URANS) solvers (e.g., HELIOS [1], FUN3D [2], and OVERFLOW [3]) are available, their utilization in maintaining a high-fidelity wake field incurs high computational cost. This has motivated the development of hybrid methods where a conventional CFD solver models the flow near the aerodynamic components and an alternate description better suited to preserving vortical structures is used for the remaining (or outer) flowfield [4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…The Lagrangian realizations comprise particle [8,9] and filament [10] vortex methods and are generally very fast, dissipationfree, and, in the case of properly connected filament descriptions, automatically maintain the divergence-free condition. On the other hand, they are topologically nonoptimal for resolving merging vortex structures, pinch-off events, or flow structures impacting a surface.…”

Section: Introductionmentioning

confidence: 99%

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Innovative Grid-Based Vorticity–Velocity Solver for Analysis of Vorticity-Dominated Flows

Whitehouse

Boschitsch

2015

AIAA Journal

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Unsteady vorticity-dominated flows are prevalent in a wide variety of engineering applications and are particularly challenging to predict efficiently. Perhaps in no other application is this more apparent than rotorcraft, where prediction is complicated by a wide variety of interactional aerodynamics between strong vortical wakes shed from rotating components and various bodies and wings immersed in the flow. While conventional computational fluid dynamics methods are equipped with the modeling capabilities to support these flow behaviors, they are subject to significant numerical diffusion whose practical import is that high computational costs involving large grids, complex adaptation methods, and high interpolation orders are required to produce sufficiently accurate simulations and prevent the artificial diffusion of vortical structures. Hybrid computational fluid dynamics methods that couple a body-fitted solver to a vorticity-velocity method hold considerable promise in alleviating these costs while effectively preserving vorticity. However, several fundamental and long-standing issues identified with vorticity-velocity methods have precluded their wider adoption. Here, the four most prominent concerns are addressed: 1) maintaining a solenoidal vorticity field; 2) supporting a low-dissipation/dispersion scheme on a general multiresolution grid; 3) providing a consistent and efficient implementation of the viscous terms; and 4) properly including the unsteady pressure contributions. Nomenclature A = angular impulse B = unsteady pressure B = normalized unsteady pressure E = energy f = flux across a surface GR; r = Green's function H = helicity I = linear impulse n = unit normal vector P = static pressure P = normalized steady pressure R = position vector with components x; y; z R = centroid of vorticity Re Γ = Reynolds number with respect to vortex ring circulation; Γ∕v r = radial location S = initial distance between vortex rings S = surface S = vorticity source term t = time U = freestream velocity u = velocity u = centroid of velocity V = volume Γ = circulation Δs = cell size ε = enstrophy η = divergence-free correction term θ = initial vortex ring inclination υ = viscosity ρ = density σ = core radius σ = pressure source term ψ = stream function Ω = integrated vorticity ω = vorticity

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Section: E Implementation Of Viscous Termsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Innovative Grid-Based Vorticity–Velocity Solver for Analysis of Vorticity-Dominated Flows

Whitehouse

Boschitsch

2015

AIAA Journal

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“…Zhao et al employ a viscous vortex particle method together with two different RANS solvers to investigate rotor wake flow. 15 Stone et al 16,17 used an overset Unsteady RANS flow solver coupled to a vortex particle method to investigate rotor blade-vortex interactions. Pahla et al 18 take a slightly different approach, whilst the domain is still decomposed into regions the Lagrangian method is applied to the entire domain whilst the Eulerian solver is only applied to the region close to the solid boundary.…”

Section: Introductionmentioning

confidence: 99%

Wingtip Vortex Preservation Using a Coupled Vortex Particle Method and Computational Fluid Dynamics Solver

Huntley¹,

Jones²,

Gaitonde³

2017

23rd AIAA Computational Fluid Dynamics Conference

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“…1,5,6,11,13,[55][56][57][58][59][60] When simulating an actuator disk with n = 225 around 20 time steps were used to reach a 3 radii convection distance with only a few minutes of computational time, while at n = 1,521, 59 time steps were required and almost 48 hours of computation.…”

Section: Simulation Resultsmentioning

confidence: 99%

A Three Dimensional Vortex Particle-Panel Code For Modeling Propeller-Airframe Interaction

Calabretta¹

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Analysis of the aerodynamic effects of a propeller flowfield on bodies downstream of the propeller is a complex task. These interaction effects can have serious repercussions for many aspects of the vehicle, including drag changes resulting in larger power requirements, stability changes resulting in adjustments to stabilizer sizing, and lift changes requiring wing planform adjustments.Historically it has been difficult to accurately account for these effects at any stage during the design process. More recently methods using Euler solvers have been developed that capture interference effects well, although they don't provide an ideal tool for early stages of aircraft design, due to computational cost and the time and expense of setting up complex volume grids. This research proposes a method to fill the void of an interference model useful to the aircraft conceptual and preliminary designer.The proposed method combines a flexible and adaptable tool already familiar to the conceptual designer in the aerodynamic panel code, with a pseudo-steady slipstream model wherein rotational effects are discretized onto vortex particle point elements. The method maintains a freedom from volume grids that are so often necessary in the existing interference models. In addition to the lack of a volume grid, the relative computational simplicity allows the aircraft designer the freedom to rapidly test radically different configurations, including more unconventional designs like the channel wing, thereby providing a much broader design space than otherwise possible.Throughout the course of the research, verification and validation studies were conducted to ensure the most accurate model possible was being applied. Once the vortex particle scheme had been verified, and the ability to model an actuator disk with vortex particles had been validated, the overall product was compared against propeller-wing wind tunnel results conducted specifically as benchmarks for numerical methods.The method discussed in this work provides a glimpse into the possibility of pseudo-steady interference modeling using vortex particles. A great groundwork has been laid that already provides reasonable results, and many areas of interest have been discovered where future work could improve the method further. The current state of the method is demonstrated through simulations of several configurations including a wing and nacelle and a channel wing. iv ACKNOWLEDGMENTS My tenure at

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Rotor Wake Modeling with a Coupled Eulerian and Vortex Particle Method

Cited by 11 publications

References 12 publications

Innovative Grid-Based Vorticity–Velocity Solver for Analysis of Vorticity-Dominated Flows

Innovative Grid-Based Vorticity–Velocity Solver for Analysis of Vorticity-Dominated Flows

Wingtip Vortex Preservation Using a Coupled Vortex Particle Method and Computational Fluid Dynamics Solver

A Three Dimensional Vortex Particle-Panel Code For Modeling Propeller-Airframe Interaction

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