Density-dependent solute transport in the hyporheic zone
Stream sediments not only host hotspots of chemical and biological processes, they also control the exchange of water and solutes between the stream and underlying aquifer. Hyporheic exchange, in water and solutes that enter the streambed and are transported within it for short distances before returning to the stream, occurs over a range of temporal and spatial scales. Nanoparticle transport in these systems was investigated in laboratory experiments. The experiments revealed the strong impact of density and bedform variations on nanoparticle fate in streambeds.
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Solute transport in stratified bedform with a low permeability layer |
Penetration of the streambed by a dense nanoparticle plume. |
Qihao Jiang, visiting PhD candidate
Collaboration with Prof. Guangqiu Jin, State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, China
Hybrid Euler-Euler/Euler-Lagrange Model for Simulating Cutting Transport during Drilling
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The Casing while Drilling (CWD) technique is widely utilized for drilling oil wellbores in onshore and offshore engineering applications. Removal of cuttings produced during drilling or hole cleaning is not easily achieved. Complicating factors arise for deviated or horizontal drilling due to the different mechanisms involved, the importance of which can vary with the ambient conditions, e.g., mixture and solid flow rates, pressure drop, wellbore stability, particle degradation and so on. Our main aims are: (i) to develop a robust numerical procedure based on a hybrid Euler-Euler/Euler-Lagrange model for simulating the transport of cuttings under high concentration conditions, (ii) to validate the two-phase model using 3D benchmark data sets, (iii) to consider the effects of various parameters including the diameter ratio between the drilling string and wellbore, rate of penetration, cutting diameter, rheological characteristics of the drilling fluid, and eccentricity ratio |
Contact: Seyed Mahmood Hamze Ziabari, visiting PhD candidate,
Collaboration with Associate Prof. Abbas Yeganeh-Bakhtiary, School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran