Related Experiment Video
Updated: Dec 20, 2025

Assembly and Characterization of an External Driver for the Generation of Sub-Kilohertz Oscillatory Flow in Microchannels
Published on: January 28, 2022
Experiments on Liquid Flow through Non-Circular Micro-Orifices
Stefano Cassineri1, Andrea Cioncolini2, Liam Smith1
1Materials Performance Centre, Department of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
Abstract:
Microfluidics is an active research area in modern fluid mechanics, with several applications in science and engineering. Despite their importance in microfluidic systems, micro-orifices with non-circular cross-sections have not been extensively investigated. In this study, micro-orifice discharge with single-phase liquid flow was experimentally investigated for seven square and rectangular cross-section micro-orifices with a hydraulic diameter in the range of 326-510 µm. The discharge measurements were carried out in pressurized water (12 MPa) at ambient temperature (298 K) and high temperature (503 K). During the tests, the Reynolds number varied between 5883 and 212,030, significantly extending the range in which data are currently available in the literature on non-circular micro-orifices. The results indicate that the cross-sectional shape of the micro-orifice has little, if any, effect on the hydrodynamic behavior. Thus, existing methods for the prediction of turbulent flow behavior in circular micro-orifices can be used to predict the flow behavior in non-circular micro-orifices, provided that the flow geometry of the non-circular micro-orifice is described using a hydraulic diameter.
Related Concept Videos
Pipe Flowrate Measurement
The orifice meter is a simple,...
Steady, Laminar Flow in Circular Tubes
Design Example: Flow of Oil Through Circular Pipes
Free Jet
Poiseuille's Law and Reynolds Number
Steady, Laminar Flow Between Parallel Plates

