Theoretical and Experimental Study of Unsteady Rotor/Body Aerodynamic Interactions

Crouse, Gilbert L.; Leishman, J. Gordon; Bi, Naipei

doi:10.4050/jahs.37.55

Cited by 28 publications

(9 citation statements)

References 14 publications

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“…The rotor wake/fuselage interaction problem, even in steady flight condition, is very complicated and highly nonlinear. There have been many research works [87,88,89,90,91,92,93,94,95,96,97,98,99,100] The fuselage panel pressure coefficients can be related to the rotor pressure coefficients through applying the pressure condition at the fuselage panel, which states that the fuselage panel pressure perturbation at the fuselage must be equal to the rotor pressure perturbation at the fuselage, that is,…”

Section: Fuselage Blockage Effectmentioning

confidence: 99%

Rotor Dynamic Wake Distortion Model for Helicopter Maneuvering Flight

Zhao¹

2004

j am helicopter soc

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Section: Fuselage Blockage Effectmentioning

confidence: 99%

Rotor Dynamic Wake Distortion Model for Helicopter Maneuvering Flight

Zhao¹

2004

j am helicopter soc

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“…The fuselage will also induce an acceleration motion tangential to the surface on the vortex. Based on the two-dimensional vortex mirror method, 18 the vortex line mirror method was adopted to account for the induced and obstructed effects of the fuselage on the rotor wake. In this method, the discretized fuselage surface panel is approximately regarded as plane mirror; each wake vortex line is constituted by two vortex points.…”

Section: Coupled Methodsmentioning

confidence: 99%

A coupled free-wake/panel method for rotor/fuselage/empennage aerodynamic interaction and helicopter trims

Cao

2014

Proceedings of the Institution of Mechanical Engineers, Part G:

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A coupled free-wake/panel method to predict the rotor downwash aerodynamic interaction and helicopter trims is presented. Free-wake method was developed to analyze aerodynamics interference of rotor wake, based on lifting-surface theory and vortex method, which relates the core radius, span station, and circulation of initial tip vortex with the blade-bound circulation distribution, and eliminates the empirical parameters during rotor free wake analysis. Helicopter fuselage with empennage was discretized into source panels. The vortex line mirror method was adopted to account for wake acceleration phenomenon that resulted from the close interaction between rotor wake and fuselage surface. The rotor wake geometry and downwash simulations were investigated including comparisons with the available measured data. Combined with the helicopter flight dynamics model and embedded in the trim procedure, the free-wake/panel coupled method was applied to calculate the rotor wake and its interference on other components of a full-scale UH-60A rotorcraft in level flight. Comparisons among predictions, referenced results, and experimental results are made for rotor wake geometries, blade-bound vortex, blade tip vortex, rotor downwash velocity, and control stick positions, and encouraging results were obtained. To validate the present method, this paper discusses the fundamental formulation, the numerical algorithms, and the simulation results.

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“…This has led to closer understanding of the interaction mechanisms and advancing the prediction capability of complete helicopter configurations. The studies can be categorized as purely experimental or experimental and theoretical work [4][5][6][7][8][9][10][11][12], simple analytical or numerical work that uses simplified aerodynamic and structural models [13][14][15][16][17][18][19][20][21][22][23], and numerically more involved work that directly solves computational fluid dynamics (CFD) equations like Euler or Navier-Stokes (in form of Reynolds-averaged Navier-Stokes = RANS) for the rotorcraft flow field [24][25][26][27][28][29][30][31][32][33][34]. Even though the direct usage of CFD is viable and sometimes desired in predicting the complicated interaction behavior accurately, it is still computationally expensive and prohibitive especially for cases within the preliminary design stage of a rotorcraft.…”

Section: Introduction and Objectivesmentioning

confidence: 99%

Semi-empirical modeling of fuselage–rotor interference for comprehensive codes: influence of side-slip angle

Wall

Yin

2016

CEAS Aeronaut J

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A semi-empirical and physics-based analytical formulation of the induced velocities generated by the fuselage shell of the Bo105 wind tunnel model in the volume around the rotor is derived from velocity data computed by a panel code. The reduced-order analytical model is several orders of magnitude faster than the panel code and thus is predestinated for use in comprehensive rotor codes. Angle of attacks investigated include vertical descent, shallow descent, level flight and climb to vertical ascent. Side-slip angles range from forward to quartering flight. The analytical induced velocity model can be directly used to account for the inflow at the blade elements and also allows for analytical or numerical integration of rotor wake convection to compute the associated displacements of rotor blade tip vortices travelling downstream within this velocity field. This model will be used to replace a fully panelized fuselage (and thus significantly reduce the computational effort) throughout a simulation with an aeromechanics code to account for the influence of the fuselage (e.g., in a design stage). The usage within an aerodynamics code (e.g., a panel code) reduces the panelization to the rotor blades only, leaving the computation of the fuselage-induced velocities to the model. The focus of this paper is the analytical evaluation of fuselagerotor interference in side-slip angles on rotor trim controls, using blade element momentum theory. The results are compared to the influence of thrust-induced inflow gradients on rotor trim.

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Theoretical and Experimental Study of Unsteady Rotor/Body Aerodynamic Interactions

Cited by 28 publications

References 14 publications

Rotor Dynamic Wake Distortion Model for Helicopter Maneuvering Flight

Rotor Dynamic Wake Distortion Model for Helicopter Maneuvering Flight

A coupled free-wake/panel method for rotor/fuselage/empennage aerodynamic interaction and helicopter trims

Semi-empirical modeling of fuselage–rotor interference for comprehensive codes: influence of side-slip angle

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