The influence of multiscale fractal geometry on the generation of turbulence

Abstract

The present research aims to study the influence of multiscale fractal geometry on the generation and decay of turbulence by spaced fractal square grid (SFSG) in order to understand how the turbulent flow is modified when it is generated at different scales. Velocity measurements were made in an open-circuit suction wind tunnel at various positions downstream of the grid in the streamwise and spanwise direction for three different inlet velocities using a constant temperature hot wire anemometer. The SFSG pattern producing a multiscale forcing of velocity is new and is the one used as the basis for this project. It was found that this space-filling grid model with relatively low solidity has the ability to generate turbulence with high turbulence intensity and high Reynolds numbers compared to the turbulence generated by fractal square grid (FSG) and regular grids at the same flow velocity. A more comprehensive understanding of this type of multiple length scales in momentum and energy transport has a key role to understand the analysis of structural implications due to the pollutant dispersion in the atmosphere.