American Society of Civil Engineers

CFD Modeling of Spillway Performance

by Dan Gessler, Ph.D., P.E., (Alden Research Laboratory Inc., 30 Shrewsbury St, Holden MA 01520; E-mail:
Section: Hydraulics and Structures, pp. 1-10, (doi:

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Document type: Conference Proceeding Paper
Part of: Impacts of Global Climate Change
Abstract: In reviewing the hydraulic performance of the overflow spillways for a dam it was found that the pool elevation during the newly computed probable maximum flood (PMF) was projected to be 10 feet higher than the design level and 26 feet above the crest of the spillways. The spillways were tested by use of a physical model in 1960 for flows up to the design flow. The objective of this study was to determine the spillway performance during the PMF. A three dimensional computational fluid dynamics (CFD) model of a portion of the lake and the two spillways was developed using FLOW-3D®. For the computational mesh, three levels of successive grid refinement were used to minimize computational time and to provide adequate resolution of the final model results. A total of about 13,000,000 computational cells were used in the models. Results of the CFD model were validated against the 1960 model study. A grid resolution study using three different grids was used to determine the sensitivity of model results to changes in grid resolution. The validated CFD model was used to predict the free falling jet trajectory and performance of the spillways under flow rates which were more than double the design the design flow.

ASCE Subject Headings:
Computational fluid dynamics technique