Convective Mass

This research area investigates the dispersion behavior of solutes in non-Newtonian Casson fluids flowing through conduits where the walls are chemically active, considering the effects of convection, diffusion, and interphase mass transfer. Accurate modeling of transport coefficients, such as dispersion, convection, and exchange coefficients, especially their time-dependent behavior and sensitivity to yield stress and wall absorption, is critical for applications ranging from biomedical to chemical engineering. The studies employ techniques including Aris-Barton's moment method, finite difference schemes, and generalized dispersion models to capture complex dynamics.

This theme focuses on observational and modeling techniques for quantifying convective mass flux in tropical cumulus clouds, a key quantity in weather and climate models that strongly influences atmospheric heat, moisture, and momentum transport. Vertical velocity retrievals from wind profilers combined with radar-derived precipitating cloud properties enable the estimation of mass flux and its components—fractional area and vertical velocity—at scales relevant to general circulation models (GCMs). This body of research addresses challenges in observing vertical velocity within clouds, parameterizing it from reflectivity data, and evaluating mass-flux schemes with long-term observational datasets.

This research focuses on the forces acting on an intruder particle—typically a differently sized or dense particle—immersed in a dense granular flow under convective or sheared conditions. By quantifying drag, buoyancy, and lift through discrete element method (DEM) simulations, these studies clarify the mechanisms behind size and density segregation in granular flows, which is vital for industrial processing and geophysical granular dynamics. Understanding how forces deviate from classical fluid analogies (e.g., Stokes’ law, Archimedean buoyancy), and their dependency on local flow structure, turbulence, and particle slip velocity, allows improved continuum models of segregation flux.