1. V.G. Kuzmenko, Ye.A. Gayev ( Institute of Hydromechanics of NASU, Kyiv, Ukraine) Large Eddy Simulation of turbulent boundary layer flow within and above an easily penetrable roughness

2. Introduction

4. Engineering aspect of the presented work lies in its applicability to a range of hydraulic water supply problems with simultaneous water filtering that is evident from Figure 2. Filter porosities A 1 and A 2 and their heights h 1 and h 2 are important design parameters. Another practical example is a duct with porous filter in the centre of the duct and empty areas near walls. One more flow pattern has been shown in the Fig. 2,C. Here, the porous filter is taken of a finite length. A vortical zone may, or may not, appear behind the filters depending on the filter heights and their densities (porosities). Another motivation of the present work was to examine validity for some simplified approaches used in wind engineering and other disciplines dealing with flows over penetrable obstruction layers [3,4,5]. Let us simulate the EPR by a local force "smeared out" within the penetrable layers and and being proportional to some power k of the local flow velocity V.

5. Conclusion

6. References 1. Schiller L. 2. Schlichting G. 3. Gayev Ye.A. Models of easily penetrable roughness for Nature and Engineering., Kiev, 2004. (to be published in Russian with extended abstract in English) 4. Finnigan J.J., Brunet Y. Turbulent airflow in forests on flat and hilly terrain. In: Wind and Trees (Edited by M.P.Coutts and J.Grace). Cambridge University Press, 1995, pp. 3 -- 40. 5. Britter R.E., Hanna S.R. Flow and Dispersion in Urban Areas. – Annual Review of Fluid Mechanics, 35, 2003, pp. 469 – 496. 6. Naot D., Nezu I., Nakagawa H. Hydrodynamic bahaviour of partly vegetated open channels. // J. of Hydraulic Engineering, pp. 625 -- 633, 1996. 7. Roach P.J. Computational Fluid Dynamics. Hermosa Publishers, Albuquerque, 1976 10. Shikhaliev S.Z. On the Efficiency of Solving of Initial-Boundary Value Problems for Parabolic Equations by Algorithm of Polynomial Acceleration. In: 4th Intern. Conf. on Inform. System, Anal. and Synth., Vol. 2, 1998. Orlando, USA, pp. 386 - 390.