Author(s): B. P. Tullis; N. L. Young; B. M. Crookston
Linked Author(s): Blake P. Tullis
Keywords: Labyrinth weir; Hydraulic modeling; Scale effect; Surface tension; Viscosity
Abstract: Physical model studies of hydraulic structures are often conducted by maintaining geometric similitude between the model and prototype to account for the dominant gravity and inertia forces while other fluid forces are assumed negligible. However, as the model size and/or the upstream total head decreases, other fluid forces can exceed negligible levels. This phenomenon is referred to generally as size-scale effects and can be a source of error in predicting prototype flow behavior. To investigate size-scale effects related to labyrinth weirs, several scaled models ranging in weir heights from 76 mm (0.25 ft) to 914mm (3.0 ft) were investigated to assess differences among head-discharge relationships and nappe behavior. Criteria to avoid sizescale effects were determined to be dependent on the model size and tolerable error.