Micro-velocimeter for an open channel flow: a simple and economical alternative

Abstract

Research related to hydraulic engineering requires microscale experiments to replicate various phenomena under dynamic conditions. An open channel flow, or also called micro-canal is used to study river floods, scour around coast structures and bridge piers scour. The need for multiple measurement water speed points, in such a way that specific sections of the micro-canal could be controlled, motivated this research. However, the acquisition of high-end speed sensors involves high economic costs being difficult to implement. As a solution, we designed and implemented a micro-velocimeter (MSV) whose operation principle is based on the operation of a small D.C. motor in generator mode. The D.C. generator shaft is turned by a small propeller, which rotates according to the water speed inside the micro-canal. The prototype was designed using AUTOCAD software, simulated by SolidWorks software and built by 3D printing. For the implementation, the MSV was calibrated using an available Acoustic-Doppler Velocimeter (ADV). The MSV is a good alternative for realizing multi-point measurements along of a micro-canal or with a matrix arranged in a specific section or both, in a simple and economical form.