DNS: Turbulent separation bubble

Direct numerical simulations (DNSs) have been carried out in a turbulent boundary layer (TBL) with separation and reattachment with focus on the effect of Reynolds number. Particular attention is given to the effect of Reynolds number. The present flow is a pressure-induced turbulent separation bubble over a flat plate where the data of a zero-pressure gradient TBL are prescribed at the inlet (x=0). The suction and blowing are imposed at the upper boundary for creating a separation bubble. The periodic boundary condition is used in the spanwise (z) direction, whereas the no-slip boundary condition is used at the wall (y=0). More details are given in the below references.

Computational domain

(Reproduced with permission from Abe (2017) © 2017 Cambridge University Press.)

Suction and blowing profile at the upper boundary (Vtop)

  • This database provides basic statistics obtained from a large magnitude of suction and blowing profile at the upper boundary (Vtop).i.e.

    $ {V_{top}} = {V_{\max }} \times \sqrt 2 \times \left( {\frac{{{x_c} - x}}{\sigma }} \right)\exp \left( {\psi - {{\left( {\frac{{{x_c} - x}}{\sigma }} \right)}^2}} \right) $

    with $ {V_{\max }} = 0.3325{\rm{ }},\,\,\,{x_c} = {10^5}/{2^9},\,\,\,\sigma = 80\sqrt 2 \left( {{5^2}/{2^5}} \right),\,\,\,\psi = 0.95$

  • This case is denoted as ‘LB case’ in the below references.

Statistics Downloads

Basic statistics for ‘LB case’ where 1D data involve mean quantities and one-point turbulence statistics and 2D data are mean velocity, TKE, turbulent eddy viscosity (νt).

Reθ0 1D data 2D data
300 DOWNLOADsep300LB.dat DOWNLOADsep300LB_2D_xy.zip
600 DOWNLOADsep600LB.dat DOWNLOADsep600LB_2D_xy.zip
900 DOWNLOADsep900LB.dat DOWNLOADsep600LB_2D_xy.zip
  • Note that Reθ0 denotes the momentum thickness Reynolds number at the inlet.

  • Also, in the present flow, ντ is obtained with the coordinate-invariant relation, i.e.
    $ {\nu _t} \equiv - \overline {{u_i}{u_j}} {S_{ij}}/2{S_{kl}}{S_{kl}} $ , where $ {S_{ij}} \equiv \left( {{U_{i,j}} + {U_{j,i}}} \right)/2 $

References

  • H. Abe, " Reynolds-number dependence of wall-pressure fluctuations in a pressure-induced turbulent separation bubble," J. Fluid Mech., Vol. 833, pp. 563-598 (2017). DOI: https://doi.org/10.1017/jfm.2017.694
  • H. Abe, “ Direct numerical simulation of a turbulent boundary layer with separation and reattachment over a range of Reynolds numbers,” Fluid Dynamics Research, Special issue: Fluid Dynamics of Near-Wall Turbulence, Vol. 51, 011409 (2019). DOI: https://doi.org/10.1088/1873-7005/aac5fc
  • In the DNSs, statistics have been obtained with maximal caution on the accuracy and convergence. Users however should remind that their accuracy is within a certain limit imposed by the grid resolution and numerical scheme employed. The database may be updated without any notification.
  • When publishing the results using the downloaded data, users should clarify the source of the data, such as by quoting the above references.
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