Experimental study of velocity fields in rectangular shallow reservoirs

Abstract

Velocity fields in rectangular shallow reservoirs with different length-to-width and expansion ratios were investigated in an experimental study, to evaluate the effect of geometry on the flow field. A wide range of combinations of these two non-dimensional geometric parameters were tested at constant hydraulic conditions. Ultrasound velocity profilers were used to measure the horizontal velocity components across the entire reservoir surface, allowing for the visualization of streamlines and of the instantaneous and average velocities. Five different types of flow patterns were identified, depending on the values of the length-to-width ratio and expansion ratio of the reservoir. Asymmetrical flow patterns were found to develop for certain combinations of these geometric parameters despite the perfect reservoir symmetry. A critical comparison of these new experimental results with those of other works is provided.

Keywords:

• Flow pattern
• geometrical effect
• instability
• large scale turbulent structure
• shallow reservoir
• velocity measurement

Acknowledgements

S. Kantoush provided helpful support and suggestions on experimentation. Thanks to M. Dufresne and B. Dewals for fruitful discussions on this research study.

Additional information

Notes on contributors

Erica Camnasio

IAHR Young Member, PhD Student

Enrico Orsi

IAHR Member

Anton J. Schleiss

IAHR Member