Wind tunnel test on spatial scall of velocity fluctuations influenced by separation flow around a roof: Fundamental study on prediction method of separation flow around building (part 1)

In predicting the complex flow field caused by the separation flow around a building, previous studies have shown that Large Eddy SimulationCLES) can be superior to Reynolds "Averaged Navier-Stokes Equations(RANS). However. LES which is applied the coarse computational grid resolution can give inadequate results from the viewpoint of the accuracy and information quantity. Therefore, understanding the scale of velocity fluctuation can be important before determining the grid resolution. This paper focuses on the influence on the various fluctuation scale which generated by the separation flow. In this paper, the filtered velocity is obtained by applying spatial filters to the data of Particle Image Velocimetry (PIV). The results indicate that data of filtered velocity do not appear to change significantly when relatively large filters are applied.