Experimental and numerical analysis of flow instabilities in rectangular shallow basins

• Published in: Environmental fluid mechanics (Dordrecht, Netherlands : 2001) Vol. 8; no. 1; pp. 31 - 54
• Main Authors: Dewals, B. J., Kantoush, S. A., Erpicum, S., Pirotton, M., Schleiss, A. J.
• Format: Journal Article Web Resource
• Language: English
• Published: Dordrecht Springer Netherlands 01-02-2008; Springer; Springer Nature B.V; Springer Science & Business Media B.V
• Subjects: Basins; Boundary conditions; Civil engineering; Classical Mechanics; Depth-averaged model; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Engineering, computing & technology; Environmental engineering; Environmental Physics; Exact sciences and technology; Finite volume; Flow pattern; Fluid mechanics; Free surfaces; Geophysics; Hydraulics; Hydrogeology; Hydrology; Hydrology. Hydrogeology; Hydrology/Water Resources; inflow; Ingénierie civile; Ingénierie, informatique & technologie; Numerical analysis; Oceanography; Original Article; outflow; Q1; Reservoir hydrodynamics; Simulation; Shallow flow; Depth-averaged model; Reservoir hydrodynamics; Stability analysis; Finite volume; models; Initial condition; hydrodynamics; digital simulation; Hydrodynamic instability; Free surface flow; growth; flow field; boundary conditions; stability
• ISSN: 1567-7419; 1573-1510; 1573-1510
• DOI: 10.1007/s10652-008-9053-z

Free surface flows in several shallow rectangular basins have been analyzed experimentally, numerically and theoretically. Different geometries, characterized by different widths and lengths, are considered as well as different hydraulic conditions. First, the results of a series of experimental tests are briefly depicted. They reveal that, under clearly identified hydraulic and geometrical conditions, the flow pattern is found to become non-symmetric, in spite of the symmetrical inflow conditions, outflow conditions and geometry of the basin. This non-symmetric motion results from the growth of small disturbances actually present in the experimental initial and boundary conditions. Second, numerical simulations are conducted based on a depth-averaged approach and a finite volume scheme. The simulation results reproduce the global pattern of the flow observed experimentally and succeed in predicting the stability or instability of a symmetric flow pattern for all tested configurations. Finally, an analytical study provides mathematical insights into the conditions under which the symmetric flow pattern becomes unstable and clarifies the governing physical processes.