Aerodynamic loading on a cylinder behind an airfoil

Zhang, H. J.; Huang, Lixi; Zhou, Yu

doi:10.1007/s00348-004-0915-y

Cited by 10 publications

(8 citation statements)

References 11 publications

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“…Then, to distinguish quantitatively the impact of the aerodynamic load and the mechanical balance measurements, a special methodology has to be performed to substract the inertial part of the load from the total measurement. This complex splitting technique has been applied in the past for side load estimation (see for example [13,26,2]). However, this kind of approach is very complex and demanding, and requires two different types of sensors: global sensors (mechanical balance) to get the overall loading and local sensors (accelerometers) for inertial corrections.…”

Section: Measuring Aerodynamic Loadmentioning

confidence: 99%

From pressure fluctuations to dynamic loads on axisymmetric step flows with minimal number of kulites

Marié¹,

Deck²,

Weiss³

2010

Computers & Fluids

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Section: Measuring Aerodynamic Loadmentioning

confidence: 99%

From pressure fluctuations to dynamic loads on axisymmetric step flows with minimal number of kulites

Marié¹,

Deck²,

Weiss³

2010

Computers & Fluids

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“…It is situations of this kind that we intend to model a) Electronic mail: fernando.mellibovsky@upc.edu here by placing a square cylinder in the interface of two streams of different velocities. In fact, the configuration in which a bluff body is placed in the wake of a streamlined body has very seldom been considered in the literature, notable exceptions being the analysis of cylinders in the wake of airfoils 6,7 . Although this problem is different than that of homogeneous upstream shear, the effects of the different velocities seen by the upper and lower sides of the bluff body are still analogous to some extent.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic performances and wake topology past a square cylinder in the interface of two different-velocity streams

et al. 2022

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We analyse the incompressible flow past a square cylinder immersed in the wake of an upstream splitter plate which separates two streams of different velocities, UT (top) and UB (bottom). The Reynolds number associated to the flow below the plate is kept constant at ReB=D UB/ν=56, based on the square cylinder side D as characteristic length. The top-to-bottom flow dissymmetry is measured by the ratio R≡ ReT/ReB∈[1,5.3]. The equivalent bulk Reynolds, taken as the mean between top and bottom changes with R in the range Re∈( ReT+ReB)/2∈[56,178]. A Hopf bifurcation occurs at R=2.1{plus minus}0.1 ( Re=86.8{plus minus}2.8), which results in an asymmetric Kármán vortex street with vortices only showing on the high-velocity side of the wake. A spanwise modulational instability is responsible for the three-dimensionalisation of the flow at R≈3.1 ( Re≈115) with associated wavelength λ z≈2.4.For velocity ratios R{greater than or equal to}4, the flow becomes spatio-temporally chaotic. The migration of the mean stagnation and base pressure points on the front and rear surfaces of the cylinder as R is increased determine the boundary layer properties on the top and bottom surfaces and, with them, the shear layers that roll up into the formation of Kármán vortices, which in turn help clarify the evolution of the lift and drag coefficients. The symmetries of the different solutions across the flow transition regime are imprinted on the top and bottom boundary layers and can therefore be analysed from the time evolution and spanwise distribution of trailing edge boundary layer displacement thickness at the top and bottom rear corners.

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“…The wake-body interaction problem usually considers a body, streamlined or bluff, placed in the wake of another bluff body. The configuration in which a bluff body is placed in the wake of a streamlined body such as we intend to address here has very seldom been considered in the literature, and then always placing a cylinder or strut in the wake of an airfoil (Zhang, Huang & Zhou 2005; Niu, Li & Wang 2021). However distant this problem may seem at first from that of an homogeneous upstream shear, the effects associated to the different velocity seen by the upper and lower sides of the bluff body might be expected – and will indeed be shown – to bear a striking resemblance.…”

Section: Introductionmentioning

confidence: 99%

Square cylinder in the interface of two different velocity streams

Mansy

Sarwar²,

Bergadà³

et al. 2022

J. Fluid Mech.

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We investigate the incompressible flow past a square cylinder immersed in the wake of an upstream nearby splitter plate separating two streams of different velocity. The bottom stream Reynolds number, based on the square side, $Re_B=56$ is kept constant while the top-to-bottom Reynolds numbers ratio $R\equiv Re_T/Re_B$ is increased in the range $R\in [1,6.5]$ , corresponding to a coupled variation of the bulk Reynolds number $Re\equiv (Re_T+Re_B)/2\in [56,210]$ and an equivalent non-dimensional shear parameter $K\equiv 2(R-1)/(R+1)\in [0,1.4667]$ . The onset of vortex shedding is pushed to higher $Re$ as compared with the square cylinder in the classic configuration. The advent of three dimensionality is triggered by a mode-C-type instability, much as reported for open circular rings and square cylinders placed at an incidence. The domain of minimal spanwise-periodic extension that is capable of sustaining spatiotemporally chaotic dynamics, namely one accommodating about twice the wavelength of the dominant eigenmode, has been chosen for the analysis of the wake transition regime. The path towards spatiotemporal chaos is, in this minimal domain, initiated with a modulational period-doubling tertiary bifurcation that also doubles the spanwise periodicity. At slightly higher values of $R$ , the flow has become spatiotemporally chaotic, but the main features of mode C are still clearly distinguishable. Although some of the nonlinear solutions found along the wake transition regime employing the minimal domain might indeed be unstable to long wavelength disturbances, they still are solutions of the infinite cylinder problem and are apt to play a relevant role in the inception of spatiotemporally chaotic dynamics.

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Aerodynamic loading on a cylinder behind an airfoil

Cited by 10 publications

References 11 publications

From pressure fluctuations to dynamic loads on axisymmetric step flows with minimal number of kulites

From pressure fluctuations to dynamic loads on axisymmetric step flows with minimal number of kulites

Aerodynamic performances and wake topology past a square cylinder in the interface of two different-velocity streams

Square cylinder in the interface of two different velocity streams

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