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Blunt Trailing Edge

The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform

Horia Hangan – 1st expert on this subject based on the ideXlab platform

  • distributed forcing flow control in the wake of a Blunt Trailing Edge profiled body using plasma actuators
    Physics of Fluids, 2015
    Co-Authors: Arash Naghiblahouti, Horia Hangan, Philippe Lavoie

    Abstract:

    A modern flow control technique for reducing the drag associated with the periodic shedding of von Karman vortices in the wake of a Blunt Trailing Edge profiled body is presented. The technique involves distributed forcing of the wake flow using an array of dielectric barrier discharge plasma actuators, with a spanwise spacing matched to the spanwise wavelength of the dominant secondary wake instability. The experiments include measurement of the velocity field in multiple vertical and horizontal planes in the wake using particle image velocimetry, as well as base pressure, at Reynolds numbers of 2000, 3000, and 5000 based on Trailing Edge thickness. The flow control technique causes elongation of the vortex formation region across the span, and significant reduction of the fluctuating and total drag forces, up to a maximum of 94% and 18%, respectively. The effectiveness of the flow control technique is shown to be dependent on the induced momentum coefficient. Proper orthogonal decomposition analysis is …

  • wake instabilities of a Blunt Trailing Edge profiled body at intermediate reynolds numbers
    Experiments in Fluids, 2014
    Co-Authors: Arash Naghiblahouti, Philippe Lavoie, Horia Hangan

    Abstract:

    Experiments have been conducted to identify and characterize the instabilities in the wake of a Blunt Trailing Edge profiled body, comprised of an elliptical leading Edge and a rectangular Trailing Edge, for a broad range of Reynolds numbers (\(2{,}000\le Re(d)\le 50{,}000\) based on the thickness of the body). These experiments, which include measurements of the wake velocity field using hot-wire anemometry and particle image velocimetry, complement previous studies of the wake flow for the same geometry at lower and higher Reynolds numbers. The spatial characteristics of the primary wake instability (the von Karman vortex street) are found to have relatively little variation in the range of Reynolds numbers investigated, in spite of the transition of the boundary layer upstream of the Trailing Edge from a laminar to a turbulent state. The dominant secondary instability, identified based on the structure of velocity and vorticity fields in the wake extracted using proper orthogonal decomposition, is found to have features similar to the ones described numerically and experimentally by Ryan et al. (J Fluid Mech 538:1–29, 2005), and Naghib-Lahouti et al. (Exp Fluids 52:1547–1566, 2012) at lower Reynolds numbers. The findings suggest that the spatial characteristics of the dominant primary and secondary wake flow instabilities have little dependence on the state of the flow upstream of the separation points, in spite of the distinct change in the normalized vortex shedding frequency upon the transition of the boundary layer.

  • Wake instabilities of a Blunt Trailing Edge profiled body at intermediate Reynolds numbers
    Experiments in Fluids, 2014
    Co-Authors: Arash Naghib-lahouti, P. Lavoie, Horia Hangan

    Abstract:

    Experiments have been conducted to identify and characterize the instabilities in the wake of a Blunt Trailing Edge profiled body, comprised of an elliptical leading Edge and a rectangular Trailing Edge, for a broad range of Reynolds numbers ( $$2{,}000\le Re(d)\le 50{,}000$$ 2 , 000 ≤ R e ( d ) ≤ 50 , 000 based on the thickness of the body). These experiments, which include measurements of the wake velocity field using hot-wire anemometry and particle image velocimetry, complement previous studies of the wake flow for the same geometry at lower and higher Reynolds numbers. The spatial characteristics of the primary wake instability (the von Kármán vortex street) are found to have relatively little variation in the range of Reynolds numbers investigated, in spite of the transition of the boundary layer upstream of the Trailing Edge from a laminar to a turbulent state. The dominant secondary instability, identified based on the structure of velocity and vorticity fields in the wake extracted using proper orthogonal decomposition, is found to have features similar to the ones described numerically and experimentally by Ryan et al. (J Fluid Mech 538:1–29, 2005 ), and Naghib-Lahouti et al. (Exp Fluids 52:1547–1566, 2012 ) at lower Reynolds numbers. The findings suggest that the spatial characteristics of the dominant primary and secondary wake flow instabilities have little dependence on the state of the flow upstream of the separation points, in spite of the distinct change in the normalized vortex shedding frequency upon the transition of the boundary layer.

Zhengyin Ye – 2nd expert on this subject based on the ideXlab platform

  • flow control over the Blunt Trailing Edge of wind turbine airfoils using circulation control
    Energies, 2018
    Co-Authors: Heyong Xu, Chenliang Qiao, Qingli Dong, Zhengyin Ye

    Abstract:

    A new partial circulation control (PCC) method is implemented on the Blunt Trailing Edge DU97-Flatback airfoil, and compared with the traditional full circulation control (FCC) based on numerical analysis. When the Coanda jet is deactivated, PCC has an attractive advantage over FCC, since the design of PCC doesn’t degrade aerodynamic characteristics of the baseline flatback section, in contrast to FCC, which is important in practical use in case of failure of the circulation control system. When the Coanda jet is activated, PCC also outperforms FCC in several respects. PCC can produce much higher lift coefficients than FCC over the entire range of angles of attack as well as the entire range of jet momentum coefficients under investigation, but with slightly higher drag coefficients. The flow field of PCC is less complex than that of FCC, indicating less energy dissipation in the main flow and hence less power expenditure for the Coanda jet. The aerodynamic figure of merit (AFM) and control efficiency for circulation control are defined, and results show that PCC has much higher AFM and control efficiency than FCC. It is demonstrated that PCC outperforms FCC in terms of effectiveness, efficiency and reliability for flow control in the Blunt Trailing Edge wind turbine application.

  • active circulation control on the Blunt Trailing Edge wind turbine airfoil
    AIAA Journal, 2017
    Co-Authors: Heyong Xu, Chenliang Qiao, Huiqiang Yang, Zhengyin Ye

    Abstract:

    Active circulation control on a thick Blunt Trailing Edge wind turbine airfoil is proposed and numerically investigated by solving Reynolds-averaged Navier–Stokes equations along with Spalart–Allma…

Philippe Lavoie – 3rd expert on this subject based on the ideXlab platform

  • spatiotemporal analysis of fluctuating base pressure and velocity in a Blunt Trailing Edge wake
    54th AIAA Aerospace Sciences Meeting, 2016
    Co-Authors: Heather A Clark, Philippe Lavoie

    Abstract:

    Three-dimensional instabilities in the wake of a Blunt Trailing Edge profiled body are examined through experimental measurements of velocity and the spanwise distribution of fluctuating surface pressure on the model rear face near separation. Spatial and temporal variability of the vortex shedding behaviour result in low-frequency modulation of the pressure signals. The time-dependent amplitude is characterized using the wavelet transform, while subsequent correlation analysis and reduced-order modelling provide quantitative evidence of the dominant influence of large-scale instabilities. The cross-correlation of the wake velocity and the surface pressure are examined in the framework of the Extended Proper Orthogonal Decomposition, through which reduced-order models of the measured variables are related to construct an empirical estimator of velocity. Implications of the observed modal correlations and the statistical signature of large-scale spatial variations are discussed in relation to the estimation of multi-scale wake phenomena.

  • distributed forcing flow control in the wake of a Blunt Trailing Edge profiled body using plasma actuators
    Physics of Fluids, 2015
    Co-Authors: Arash Naghiblahouti, Horia Hangan, Philippe Lavoie

    Abstract:

    A modern flow control technique for reducing the drag associated with the periodic shedding of von Karman vortices in the wake of a Blunt Trailing Edge profiled body is presented. The technique involves distributed forcing of the wake flow using an array of dielectric barrier discharge plasma actuators, with a spanwise spacing matched to the spanwise wavelength of the dominant secondary wake instability. The experiments include measurement of the velocity field in multiple vertical and horizontal planes in the wake using particle image velocimetry, as well as base pressure, at Reynolds numbers of 2000, 3000, and 5000 based on Trailing Edge thickness. The flow control technique causes elongation of the vortex formation region across the span, and significant reduction of the fluctuating and total drag forces, up to a maximum of 94% and 18%, respectively. The effectiveness of the flow control technique is shown to be dependent on the induced momentum coefficient. Proper orthogonal decomposition analysis is …

  • wake instabilities of a Blunt Trailing Edge profiled body at intermediate reynolds numbers
    Experiments in Fluids, 2014
    Co-Authors: Arash Naghiblahouti, Philippe Lavoie, Horia Hangan

    Abstract:

    Experiments have been conducted to identify and characterize the instabilities in the wake of a Blunt Trailing Edge profiled body, comprised of an elliptical leading Edge and a rectangular Trailing Edge, for a broad range of Reynolds numbers (\(2{,}000\le Re(d)\le 50{,}000\) based on the thickness of the body). These experiments, which include measurements of the wake velocity field using hot-wire anemometry and particle image velocimetry, complement previous studies of the wake flow for the same geometry at lower and higher Reynolds numbers. The spatial characteristics of the primary wake instability (the von Karman vortex street) are found to have relatively little variation in the range of Reynolds numbers investigated, in spite of the transition of the boundary layer upstream of the Trailing Edge from a laminar to a turbulent state. The dominant secondary instability, identified based on the structure of velocity and vorticity fields in the wake extracted using proper orthogonal decomposition, is found to have features similar to the ones described numerically and experimentally by Ryan et al. (J Fluid Mech 538:1–29, 2005), and Naghib-Lahouti et al. (Exp Fluids 52:1547–1566, 2012) at lower Reynolds numbers. The findings suggest that the spatial characteristics of the dominant primary and secondary wake flow instabilities have little dependence on the state of the flow upstream of the separation points, in spite of the distinct change in the normalized vortex shedding frequency upon the transition of the boundary layer.