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AWI Presents: Water H.U.B. Talks series; An opportunity for researchers to come together.
February 12 @ 12:00 pm - 1:00 pm
Title: Hydrodynamic Driven Dissolution In Carbonate Formations: Application to Sinkhole Formation Investigation
The extremes of rainfall, extended drought seasons, and groundwater overuse accelerate the formation of sinkholes. In the United States, 20% of the land surface is karst and susceptible to sinkhole formation, especially in Texas, Alabama, Missouri, Kentucky, Tennessee, Pennsylvania, and Florida. Despite the increased risk due to climatological changes, water resources management policies, and human activities, few models exist to predict the formation and evolution of sinkholes. The objective of this research is to improve our understanding of the complex process of sinkhole formation and evolution and to investigate the hydrological and geological features controlling the development of sinkholes. It takes more than 10,000 years for soil to wash into a cavity/fissure less than 1 meter wide, but the sinkhole may develop within hours. Rapid transport of acidified rainwater through carbonate rock with nonuniform pore space results in continuous dissolution and widening cavities/fissures in vadose zone. This is because the high fluid velocity maintains the concentration gradient and provides a fresh source of the solvent which facilitates dissolution. Traditionally, multiple simplifications are applied to the flow modeling in carbonates with cavities/ fissures, which results in inaccurate mineral dissolution rates. The full analytical solutions for a Darcy-Stokes/ Darcy-Navier Stokes system is coupled to the reactive transport system for calcite dissolution in acidified brine. It is shown that based on the cavity/fissure and the rock characteristics, internal vorticities may form, therefore, the cavity/fissure may participate fully or partially in the overall flow. Hydrodynamics enforced by the presence of cavity/fissure is a key player in defining the dissolution rate and dissolution hotspots. A sequential non-iterative approach is applied to handle the coupling between hydrodynamics and mineral dissolution. Effective reaction rate together with dissolution hotspots are investigated for various rock pore structures and the most influential parameters affecting the dissolution process are obtained.
R.S.V.P. by February 7, 5 pm to email@example.com.
Boxed lunches will be provided if R.S.V.P. is received by deadline.