Comparison of 1D and 3D Hydrodynamic Models in Designing a Hydraulic Object of a Dry Reservoir

Abstract

This article describes and compares computational and result differences in 1D and 3D hydrodynamic models, which are used for capacity assessment of flow control structures. The paper focuses on a considered dry retention reservoir located on the Kotojedka stream near the city of Kroměříž, Czech Republic. Based on project documentation, a detailed 1D steady hydrodynamic model using functions of Microsoft Excel and its native VBA language was created for the functional object. The parameters of the functional object were optimized based on the results of the 1D model. During the 1D analysis, some uncertainties occurred which cannot be addressed using standard or even more complex hydraulic analytical methods, such as formation and course of hydraulic jump, manifestation of overflow and bottom inlet submergence and water surface elevation profile in apron. Experimental physical model research was not undertaken in this case due to the high cost of the model relative to its lower significance compared to other, much larger water structures. Therefore a 3D steady hydrodynamic model could bring the required solution in this case and provide the basis for object parameters optimisation. A 3D model was created using Flow – 3D software. The results were compared on a series of QN flow rates from Q10 to Q10000, where QN represents the discharge with a repetition period of once in every N years.