Te Waipounamu, the South Island of New Zealand, contains many braided rivers where the riverbed often consists of coarse gravel and pebbles. The riverbed is therefore a porous medium, which enables the water to penetrate through the spaces between individual solid grains. Furthermore, the mean speed and dynamics of the turbulent river flowing above is affected by the porous media. Understanding the influence of riverbed porosity and permeability is therefore critical for predicting discharge rates, biogeochemical processes and ultimately river health.
This project will utilise commercial computational fluid dynamics (CFD) packages (e.g. ANSYS CFX) to simulate a turbulent fluid flow passing over porous media representing a gravel riverbed. Different porosities and permeabilities will be studied, with comparisons made to experimental and high-fidelity CFD data available in the literature. The changes to the turbulent water flow (e.g. bed friction and mean flow rates) can be analysed. The CFD data can also enable the sediment-water interface to be studied to better understand the hyporheic zone, which plays an important role for stream ecosystems.
Undergraduate
Students should be enrolled in MECHENG 712 (Aerohydrodynamics) in semester 1 and, if possible, MECHENG 718 (Computational Fluid Dynamics) in semester 2. Students should have passed MECHENG 325.
Research Computation Lab (405.956A, Lab)