Measurements of velocity distribution and flow rate by using spatiotemporal filter velocimetry

Abstract

Measurements of flow rate and velocity distribution in a cross-section of a channel are often required in design and development of pipelines in industrial plants. In this study, a simple method using inclined laser sheets was developed for measuring a distribution of the axial component of velocity in a transparent channel. The velocity was measured by using spatiotemporal filter velocimetry (SFV). A measurement method of flow rate was also proposed for developed and developing channel flows. The developed systems were applied to developed and developing flows in a square duct at various Reynolds numbers covering laminar and turbulent flows. Experimental results confirmed that the method can accurately measure axial-velocity distributions over the cross-section of the duct not only in developed flows but also in developing flows. The developed method for flow rate also accurately measures the flow rate of laminar and turbulent flows in the duct under developed and developing conditions. The measurement error in flow rates was to within 3% for developed and developing flows.