GHD has been using Computational Fluid Dynamics (CFD) simulation methodologies to assist in the analysis and design services for dam safety reviews and dam upgrade designs for nearly a decade to the benefit of our clients.
Advancements in CFD software coupled with recent investments in High Performance Computing (HPC) solver infrastructure mean that our growing CFD team at GHD can undertake such studies at greater breadth of scale and in finer detail than ever before.
Many of the dam projects we work on also feature legacy Physical Hydraulic Model (PHM) studies from their initial design and construction periods. These present valuable opportunities to validate our numerical models against associated PHM data and confirm confirm that our CFD representations of the structure are accurately reproducing key hydraulic behaviours as critical inputs for design. The modelling techniques derived from these repeated PHM validation exercises also inform our modelling approaches in other water industry CFD applications which feature free surface or highly turbulent flows.
A recent example of GHD's CFD simulation services is shown in the video below, which forms part of the recent dam safety review of Eucumbene Dam undertaken for Snowy Hydro Limited.
The video shows a cycle-through of different free surface velocity views for the gated spillway of Eucumbene Dam under a single design flow event - the Maximum Flood Level scenario.
One of the great benefits of CFD simulation is that once a baseline model environment is established, different flow events and geometric arrangements can be tested quickly to gain a comprehensive understanding of the spillway performance under a range of different operating scenarios.
The simulation of flows through these structures enables GHD's design team to interrogate the CFD model results, providing technical information relevant to various aspects of dam spillway design, including:
- Environmental analysis, including fish passage suitability
- Structural analysis (hydrodynamic forces, moments and wall pressures relevant to spillway crests, spillway gates, slab uplift, chute walls, plunge pools and stilling basin design)
- Scour protection (bed shear values, impact velocities, identification of rollers and recirculation zones)
- Analysis of hydraulic performance (spillway and sluice-gate discharges for clarification of rating curves, head loss analysis, assessment of hydraulic jump formation and energy dissipation in stilling basins, identification of potential sedimentation zones, normalisation of approach flows etc.).
Examples of different post-processing results useful for engineering purposes are shown below for a single design event from the Eucumbene spillway model. For any visual representation of the post-processing results shown below, equivalent numerical plots can also be extracted for further use in programs such as Microsoft Excel.
Using CFD methods effectively in an engineering context can be a challenging exercise. It requires a cocktail of specialist skills in complex modelling software packages, solid underlying knowledge of the principles of fluid mechanics, practical IT skills for managing HPC cluster infrastructure, and above-average communication techniques to make a good CFD operator – and throw in a healthy dose of artistic flair to make a great one!
GHD has a strong record in CFD modelling in water industry applications that has been developed over the course of the last decade. Our CFD modelling has underpinned the design and analysis for many large infrastructure projects in Australia and globally. GHD’s broad array of engineering services means that the CFD modelling team is able to draw on specialised knowledge from the many complementary disciplines from within the company to support the successful delivery of your project.
For more information, connect with our professional:
James Apostolidis
CFD Coordinator - Brisbane, Australia
+61 7 3316 4182
Email James Apostolidis
James Willey
Senior Technical Director - Dams
+61 7 3316 3707
Email James Willey
Thomas Ewing
CFD Coordinator - Melbourne, Australia
+61 3 8687 8698
Email Thomas Ewing