On the Turbulence Properties of Channel Flows with Suction

This experimental study investigates the effects of membrane-induced suction on turbulent flow characteristics within a rectangular channel at a Reynolds number of 1000. Benchmark tests without the membrane confirmed the fully turbulent nature of the flow at this Reynolds number, making it a suitable choice for the study. Suction was generated by adjusting the bulk pressure within the test section and modifying pump frequency. Laser Doppler anemometry (LDA) was employed to measure velocity fluctuations, enabling the quantification of turbulence intensity and kinetic energy. Results demonstrate a significant reduction in both turbulence intensity and kinetic energy under various suction conditions compared to the benchmark case. Surprisingly, the turbulent intensity was found to be independent of the suction rate. The analysis reveals that suction effectively dampens turbulent eddies, particularly near the membrane surface. The study further explores the relationship between suction rate and turbulent flow properties. It was observed that the distribution of turbulent kinetic energy remained relatively consistent across different suction rates within the scope of these experiments. The findings of this research have important implications for the design and optimization of membrane-based processes. By understanding the effects of suction on turbulence in rectangular channels, it is possible to improve membrane performance, reduce fouling, and enhance overall system efficiency. Future studies should concentrate on exploring the influence of membrane types, varying Reynolds numbers on turbulent flow dynamics in the presence of suction.