Location of Repository

Efficient generation of inflow conditions for large-eddy simulation of street-scale flows

By Zheng-Tong Xie and Ian P. Castro


Using a numerical weather forecasting code to provide the dynamic largescale inlet boundary conditions for the computation of small-scale urban canopy flows requires a continuous specification of appropriate inlet turbulence. For such computations to be practical, a very efficient method of generating such turbulence is needed. Correlation functions of typical turbulent shear flows have forms not too dissimilar to decaying exponentials. A digital-filter-based generation of turbulent inflow conditions exploiting this fact is presented as a suitable technique for large eddy simulations computation of spatially developing flows. The artificially generated turbulent inflows satisfy the prescribed integral length scales and Reynoldsstress-tensor. The method is much more efficient than, for example, Klein’s (J Comp Phys 186:652–665, 2003) or Kempf et al.’s (Flow Turbulence Combust 74:67–84, 2005) methods because at every time step only one set of two-dimensional (rather than three-dimensional) random data is filtered to generate a set of two-dimensional data with the appropriate spatial correlations. These data are correlated with the data from the previous time step by using an exponential function based on two weight factors. The method is validated by simulating plane channel flows with smooth walls and flows over arrays of staggered cubes (a generic urban-type flow). Mean velocities, the Reynolds-stress-tensor and spectra are all shown to be comparable with those obtained using classical inlet-outlet periodic boundary conditions. Confidence has been gained in using this method to couple weather scale flows and street scale computations

Topics: GE, QA75, TA
Year: 2008
OAI identifier: oai:eprints.soton.ac.uk:52402
Provided by: e-Prints Soton

Suggested articles



  1. (2003). A digital filter based generation of inflow data for spatially developing direct numerical simulation or large eddy simulation. doi
  2. (2004). A posteriori tests of inflow conditions for large-eddy simulation, doi
  3. (2006). A synthetic-eddy-method for generating inflow conditions for large eddy simulation, doi
  4. (2002). Comparisons of model simulations with observations of mean flow and turbulence within simple obstacle arrays, doi
  5. (2002). Database for fully developed channel flow,
  6. (1994). Direct numerical simulation of turbulent flow over a backward-facing step, doi
  7. (1997). Direct numerical simulation of turbulent flow over a backwardfacing step, doi
  8. (2005). Efficient generation of initial- and inflow-conditions for transient turbulent flows in arbitrary geometries. doi
  9. (2003). Flow and dispersion in urban areas, doi
  10. (2004). Generation of inflow data for inhomogeneous turbulence, doi
  11. (2004). Generation of three-Dimensional turbulent inlet conditions for large-eddy simulation, doi
  12. (2006). Generation of turbulent inflow conditions for large eddy simulation from stereoscopic PIV mearurements, doi
  13. (1998). Generation of turbulent inflow data for spatially developing boundary layer simulation. doi
  14. (1997). Generation of velocity fluctuations for inflow boundary conditions of LES, doi
  15. (2004). Interfacing statistical turbulence closures with large-eddy simulation, doi
  16. (1994). Lagrangian PDF methods for turbulent flows, doi
  17. (2006). Large-eddy simulation for urban micro-meteorologyr, doi
  18. (2003). Large-eddy simulation of transonic turbulent flow over a bump, doi
  19. (2006). LES and RANS for turbulent flow over arrays of wall-mounted cubes, doi
  20. (2005). LES for flow over urban-like surfaces,
  21. (2003). LES of flow over multiple cubes. doi
  22. (2001). Measurement of Lagrangian velocity in fully developed turbulence. doi
  23. (2007). Novel implementation and accessment of a digtial filter based approach for the generation of LES inlet conditions, doi
  24. (2004). On inflow boundary conditions for large eddy simulation of turbulent swirling jets.
  25. (1991). Reynolds number effects in Lagrangian stochastic models of turbulent dispersion, doi
  26. (1992). Simulation of spatially evolving compressible turbulence and the application of taylors hypothesis, doi
  27. (2006). Synthetic turbulence inflow conditions for large-eddy simulation, doi
  28. (2006). The impact of urban areas on weather, doi
  29. (2006). Turbulence over urban-type roughness: deductions from wind tunnel measurements, doi
  30. (1987). Turbulence statistics in fully developed channel flow at low Reynolds number, doi
  31. (1999). Vortex structure and heat transfer in turbulent flow over a wall-mounted matrix of cubes, doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.