Langley Research Center Turbulence Modeling Resource

DNS: 2-D Converging-Diverging Channel, Re=12600

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The data on this page were provided by J.-P. Laval.

Compare this DNS data with LES data for the same configuration (at different Reynolds number): LES: 2-D Converging-Diverging Channel, Re=20580.

This DNS case is for 2-D separating flow over a converging-diverging channel with Re_tau of approximately 600, Re=12600 (based on inlet conditions). The DNS was run using an incompressible code, and has been documented in several publications:

• Marquillie, M., Ehrenstein, U., and Laval, J.-P., 2011. Instability of Streaks in Wall Turbulence with Adverse Pressure Gardient. J. Fluid Mech. 681, pp. 205-240, https://doi.org/10.1017/jfm.2011.193.
• Laval, J.-P. and Marquillie, M., 2010. Direct Numerical Simulations of Converging-Diverging Channel Flow, in "Progress in Wall Turbulence: Understanding and Modelling," Villeneuve d'Ascq, France, April 21-23, 2009 M. Stanislas, J. Jimenez and I. Marusic editors, Springer, ERCOFTAC Series, pp 203-210.
• Marquillie, M., Laval, J.-P., and Dolganov, R., 2008. "Direct Numerical Simulation of a Separated Channel Flow with a Smooth Profile," J. of Turbulence, Vol. 9, No. 1, pp. 1-23. (described numerical procedure), https://doi.org/10.1080/14685240701767332.

This is a subset of the data available from the LML Database, Case DB3b (web link no longer available).

Some relevant information is given here, but the interested reader is referred to the above publications (or LML website) for complete details:

• Hill crest is approx 2/3 units high, at location near x=5.21564
• Channel half-height = h = 1 unit (full channel height = 2h)
• Reynolds number = 12600 based on channel half-height (h), Umax at inlet, and kinematic viscosity (nu) at inlet
• The inlet channel flow is fully developed

Long-time averaged DNS data are provided below. These results are from a grid with approximately 511 million grid points, covering a spanwise extent of Pi (3.14159...) with 576 cells in the spanwise direction. Note that the files with field results on one plane of the full grid (385 x 2304) are very large, so for convenience the field results are also given in files containing only every other point (193 x 1152). Additional details about the DNS grid and methodology can be found in the above references.

• Lower wall surface points
• README_data_conv_div.pdf
  • Note picture on page 1 of the pdf file does not have the same x-positioning as the current case
  • Note dissipation and viscous diffusion terms do not include "nu" factor, which = 1/12600
  • Note dissipation is only half the intended value that should appear in the Reynlods stress balance
   
• README_meanflow_conv_div.txt
• Mean flow, velocity derivatives, and Reynolds stresses (all points from DNS), gzipped file conv-div-mean.dat.gz (70 MB)
• Mean flow, velocity derivatives, and Reynolds stresses (every second point from DNS), gzipped file conv-div-mean-half.dat.gz (16 MB)
   
• README_budgets_conv_div.txt
• Budget terms (all points from DNS), gzipped file conv-div-budgets.dat.gz (241 MB)
• Budget terms (every second point from DNS), gzipped file conv-div-budgets-half.dat.gz (55 MB)
   
• Wall Quantities

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Last Updated: 11/05/2021