Turbulent Boundary Layer

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N A Adams - One of the best experts on this subject based on the ideXlab platform.

  • analysis of unsteady behaviour in shockwave Turbulent Boundary Layer interaction
    Journal of Fluid Mechanics, 2012
    Co-Authors: Muzio Grilli, Peter J. Schmid, Stefan Hickel, N A Adams
    Abstract:

    The unsteady behavior in shockwave Turbulent Boundary Layer interaction is investi- gated by analyzing results from a LES of a supersonic Turbulent Boundary Layer over a compression-expansion ramp. The interaction leads to a very-low-frequency motion near the foot of the shock, with a characteristic frequency that is three orders of magnitude lower than the typical frequency of the incoming Boundary Layer. Wall pressure data are first analyzed by means of Fourier analysis, highlighting the low-frequency phenomenon in the interaction region. Furthermore, the flow dynamics are analyzed by a dynamic mode decomposition which shows the presence of a low-frequency mode associated with the pulsation of the separation bubble and accompanied by a forward-backward motion of the shock.

  • Analysis of unsteady behavior in shockwave Turbulent Boundary Layer interaction
    Journal of Fluid Mechanics, 2012
    Co-Authors: Muzio Grilli, Stefan Hickel, Peter Schmid, N A Adams
    Abstract:

    The unsteady behaviour in shockwave Turbulent Boundary Layer interaction is investigated by analysing results from a large eddy simulation of a supersonic Turbulent Boundary Layer over a compression-expansion ramp. The interaction leads to a very-low-frequency motion near the foot of the shock, with a characteristic frequency that is three orders of magnitude lower than the typical frequency of the incoming Boundary Layer. Wall pressure data are first analysed by means of Fourier analysis, highlighting the low-frequency phenomenon in the interaction region. Furthermore, the flow dynamics are analysed by a dynamic mode decomposition which shows the presence of a low-frequency mode associated with the pulsation of the separation bubble and accompanied by a forward-backward motion of the shock.

Muzio Grilli - One of the best experts on this subject based on the ideXlab platform.

  • analysis of unsteady behaviour in shockwave Turbulent Boundary Layer interaction
    Journal of Fluid Mechanics, 2012
    Co-Authors: Muzio Grilli, Peter J. Schmid, Stefan Hickel, N A Adams
    Abstract:

    The unsteady behavior in shockwave Turbulent Boundary Layer interaction is investi- gated by analyzing results from a LES of a supersonic Turbulent Boundary Layer over a compression-expansion ramp. The interaction leads to a very-low-frequency motion near the foot of the shock, with a characteristic frequency that is three orders of magnitude lower than the typical frequency of the incoming Boundary Layer. Wall pressure data are first analyzed by means of Fourier analysis, highlighting the low-frequency phenomenon in the interaction region. Furthermore, the flow dynamics are analyzed by a dynamic mode decomposition which shows the presence of a low-frequency mode associated with the pulsation of the separation bubble and accompanied by a forward-backward motion of the shock.

  • Analysis of unsteady behavior in shockwave Turbulent Boundary Layer interaction
    Journal of Fluid Mechanics, 2012
    Co-Authors: Muzio Grilli, Stefan Hickel, Peter Schmid, N A Adams
    Abstract:

    The unsteady behaviour in shockwave Turbulent Boundary Layer interaction is investigated by analysing results from a large eddy simulation of a supersonic Turbulent Boundary Layer over a compression-expansion ramp. The interaction leads to a very-low-frequency motion near the foot of the shock, with a characteristic frequency that is three orders of magnitude lower than the typical frequency of the incoming Boundary Layer. Wall pressure data are first analysed by means of Fourier analysis, highlighting the low-frequency phenomenon in the interaction region. Furthermore, the flow dynamics are analysed by a dynamic mode decomposition which shows the presence of a low-frequency mode associated with the pulsation of the separation bubble and accompanied by a forward-backward motion of the shock.

Philipp Schlatter - One of the best experts on this subject based on the ideXlab platform.

  • global effect of local skin friction drag reduction in spatially developing Turbulent Boundary Layer
    Journal of Fluid Mechanics, 2016
    Co-Authors: Alexander Stroh, Yosuke Hasegawa, Philipp Schlatter, Bettina Frohnapfel
    Abstract:

    A numerical investigation of two locally applied drag-reducing control schemes is carried out in the configuration of a spatially developing Turbulent Boundary Layer (TBL). One control is designed ...

  • on the fluctuating wall shear stress in zero pressure gradient Turbulent Boundary Layer flows
    Physics of Fluids, 2011
    Co-Authors: Ramis Orlu, Philipp Schlatter
    Abstract:

    Recent direct numerical simulation (DNS) results relating to the behavior of the fluctuating wall-shear stress τw,rms+ in Turbulent Boundary Layer flows are discussed. This new compilation is motivated by a recent article [Wu and Moin, “Transitional and Turbulent Boundary Layer with heat transfer,” Phys. Fluids 22, 085105 (2010)], which indicates a need for clarification of the value of τw,rms+. It is, however, shown here, based on other recent DNS data, that most results, both in Boundary Layer and channel geometry, yield τw,rms+≈0.4 plus a small increase with Reynolds number coming from the growing influence of the outer spectral peak. The observed discrepancy in experimental data is mainly attributed to spatial resolution effects, as originally described by Alfredsson et al. [“The fluctuating wall-shear stress and the velocity field in the viscous subLayer,” Phys. Fluids 31, 1026 (1988)].

Richard D Whalley - One of the best experts on this subject based on the ideXlab platform.

  • Turbulent Boundary Layer control with plasma actuators
    Philosophical Transactions of the Royal Society A, 2011
    Co-Authors: Kwingso Choi, Timothy Jukes, Richard D Whalley
    Abstract:

    This paper reviews Turbulent Boundary-Layer control strategies for skin-friction reduction of aerodynamic bodies. The focus is placed on the drag-reduction mechanisms by two flow control techniques—spanwise oscillation and spanwise travelling wave, which were demonstrated to give up to 45 per cent skin-friction reductions. We show that these techniques can be implemented by dielectric-barrier discharge plasma actuators, which are electric devices that do not require any moving parts or complicated ducting. The experimental results show different modifications to the near-wall structures depending on the control technique.

Stefan Hickel - One of the best experts on this subject based on the ideXlab platform.

  • analysis of unsteady behaviour in shockwave Turbulent Boundary Layer interaction
    Journal of Fluid Mechanics, 2012
    Co-Authors: Muzio Grilli, Peter J. Schmid, Stefan Hickel, N A Adams
    Abstract:

    The unsteady behavior in shockwave Turbulent Boundary Layer interaction is investi- gated by analyzing results from a LES of a supersonic Turbulent Boundary Layer over a compression-expansion ramp. The interaction leads to a very-low-frequency motion near the foot of the shock, with a characteristic frequency that is three orders of magnitude lower than the typical frequency of the incoming Boundary Layer. Wall pressure data are first analyzed by means of Fourier analysis, highlighting the low-frequency phenomenon in the interaction region. Furthermore, the flow dynamics are analyzed by a dynamic mode decomposition which shows the presence of a low-frequency mode associated with the pulsation of the separation bubble and accompanied by a forward-backward motion of the shock.

  • Analysis of unsteady behavior in shockwave Turbulent Boundary Layer interaction
    Journal of Fluid Mechanics, 2012
    Co-Authors: Muzio Grilli, Stefan Hickel, Peter Schmid, N A Adams
    Abstract:

    The unsteady behaviour in shockwave Turbulent Boundary Layer interaction is investigated by analysing results from a large eddy simulation of a supersonic Turbulent Boundary Layer over a compression-expansion ramp. The interaction leads to a very-low-frequency motion near the foot of the shock, with a characteristic frequency that is three orders of magnitude lower than the typical frequency of the incoming Boundary Layer. Wall pressure data are first analysed by means of Fourier analysis, highlighting the low-frequency phenomenon in the interaction region. Furthermore, the flow dynamics are analysed by a dynamic mode decomposition which shows the presence of a low-frequency mode associated with the pulsation of the separation bubble and accompanied by a forward-backward motion of the shock.