Influence the geometry of the compound channel in the formation of coherent structures

Tiago de Melo¹; Jhon N. V. Goulart¹; Carla Tatiana Mota Anflor¹

¹ Grupo de Mecânica Experimental e Computacional - GMEC - Universidade de Brasília - UnB

doi:10.20906/CPS/COB-2015-0464

Resumo

Turbulent flow in channels with gap is still a challenge for engineering. The experimental study was performed in a closed compound channel under steady state incompressible air flow. Hot wire probe was employed to measure time-serie velocities. Test sections were formed by two parallel plates attached on a side wall of a wind channel, forming a slot with width D and depth P. In this paper 8 test sections were investigated covering P/D-ratio from 3.33 up to 5.00, under the same Reynolds number. The main results showed that the dinamical characteristics of the turbulent flow in these structures are not depentend only on P/D-ratio, but the test section's length plays an important role. The Wavelet transform was used for analyze non-stationary time series, well as PSD (Power Spectro Density Function), in the identification coherent structures in the flow, in channel gap.

Palavras-chave: compound channels; turbulent flow; large scale structures; Wavelet transform; PSD