Analytical and numerical modeling of non-isothernal, multiphase and multicomponent flow in synthetic and natural porous medium. Investigation of the physical phenomena involved in heat-driven coupled processes. Analysis of simultaneous flow of heat, water, and water-vapor in disordered media.
Development and application of conceptual and mathematical models to advance our understanding of fluid flow, and of transport of chemical, biological and radioactive contaminants by groundwater in an unsaturated medium.
Mathematical modeling of spreading of non-aqueous phase liquids from underground storage tanks into soils.
Designing and performing flow and transport field tests in unsaturated porous media, and development of interpretation methods.
Modeling of drying and transport of moisture in porous solids including food materials.
Modeling of flow of leachates and gases in municipal solid waste landfills (in proposal development stage)
Conceptual and mathematical modeling and simulation of the complex physical processes associated with emplacement of extremely hot (industrial and radioactive) waste materials in the subsurface. The extreme heat may lead to mechanical deformation of the container, thereby releasing the waste materials into the subsurface environment, and subsequently polluting the potable and agricultural water system. In addition, heat emanating from the waste materials leads to vaporization of pore water, which may carry the contaminants faster through the subsurface polluting a large area in a relatively short time. Understanding of the heat driven flow and transport of waste materials is thus critical to proper isolation of (industrial and radioactive) wastes (at LBNL).
Experimental and theoretical studies of complex countercurrent flow of vapor away from the source of heat and that of condensate flowing back towards the source in a highly heterogeneous porous medium (at LBNL).
Studies of the coupled transport of non-Newtonian fluids and heat. Extensive studies of coupled transport of air/water/water vapor and heat in porous medium (at LBNL).
Designing, pretest predictive analysis, and development of modeling techniques for the Drift Scale Test, the largest and most complex in-situ thermal test being conducted in conjunction with emplacement of hot high-level radioactive wastes at Yucca Mountain, Nevada (at LBNL).
Development of innovative statistical measures to analyze the test results from the Drift Scale Test (at LBNL).
SINGLE AND MULTIPHASE TRANSPORT IN SOILS
Development of a numerical algorithm based on Laplace transform method to efficiently simulate the slow transport of contaminants. Conventional "time-marching" schemes, such as the finite-difference and finite-element methods, are not suitable for such simulations as they are computationally very demanding (while at Purdue).
Development of a technique based on fractal representation of a complex heterogeneous porous medium to model the diffusive transport of volatile pollutants from non aqueous-phase liquids leaking from underground storage tanks into soil (while at Purdue).
Proposed and successfully demonstrated how a novel correlated percolation scheme can be used to model the disorder in a highly heterogeneous porous medium, whose physical properties are functions of their positions. This has subsequently become an accepted practice in the research community in preference to classical percolation (while at Purdue).
Developed a network representation of a natural heterogeneous porous medium. Extensively investigated, applying Monte Carlo simulation methods, how the correlations in the physical properties of the medium and the disorder in the medium affect the speed and extent of transport of contaminants (while at Purdue).
Suggested scaling laws for the thickness of the mixing zones associated with convective-diffusive transport of tracer particles in disordered porous medium. Developed scaling laws for the first and second moments of the first passage probability density functions associated with the above problem. Demonstrated how the correlations and disorder in the medium alter the scaling laws. These scaling laws have been since successfully employed by other researchers in deriving scaling laws for related problems (while at Purdue).
EFFECTIVE FLOW AND TRANSPORT PROPERTIES
Investigation of the effect of correlations and disorder on the effective transport properties of heterogeneous porous media (while at USC).
Development of upscaling techniques to describe transport in porous medium with multiple scales of heterogeneities (while at USC).
Proposed and successfully developed semi-analytical schemes to compute effective transport properties of anisotropic heterogeneous porous medium. Such methods were not available before (while at USC).
HEAT DRIVEN FLOW OF NON-NEWTONIAN FLUIDS
Development of a mathematical model to describe flow of non-Newtonian fluids in a porous medium with strong temperature gradients in connection with enhanced recovery of petroleum crude through application of heat (while with Oil and Natural Gas Commission of India).
LOSS OF COOLANT ACCIDENTS
Modeling of the momentum, heat and mass transfer characteristics associated with loss of coolants (water or heavy water) from nuclear power reactors. This project was funded by the Bhaba Atomic Research Center, Bombay, India (while with Flotherm Consultants Pvt. Ltd.).