Mixing in turbulent flows

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In both nature and the man-made world, turbulent flows are the norm (laminar flows being the exception). Fundamental to them is their capacity to rapidly mix mass, momentum or energy – an attribute that underlies a wide range of processes, including aerodynamics, meteorology, combustion, and environmental pollutant dispersion. The main goal of the present proposal is to provide novel insights into the mixing process within turbulent flows by way of original, innovative research. To this end, my long-term objectives are four-fold: 1) to undertake careful, state-of-the-art experiments that will provide new perspectives on turbulent mixing, 2) to train HQP at the undergraduate, master's and doctoral levels, 3) to conceive of new experimental methods and tools for the development of innovative technologies benefitting both my research group and the general turbulence community, and 4) to provide reliable datasets of detailed, high-quality measurements in turbulent flows to those scientists and engineers who simulate and model turbulence, so they can validate their simulations/models.****** To accomplish these long-term objectives, the present application proposes a complementary set of projects relevant to the mixing of scalars (e.g., temperature, chemical species concentration) in turbulent flows. The five research projects pertain to: 1) quantification of the effect of background turbulence on the mixing within free-shear flows, 2) mixing at high Reynolds and Péclet numbers, 3) simultaneous mixing of multiple scalars within turbulent flows, 4) scalar dispersion over a porous surface/boundary, and 5) the effect of turbulent heat transfer above snow and ice surfaces. The results of this research will be of immediate relevance to workers in the fields of combustion, environmental pollutant dispersion, and climate modelling. The research program will also train HQP in turbulent flows, and thermofluids in general, supplying skilled professionals to the local aerospace, hydropower, automotive, etc. industries.****** Given the acquisition in the last 5 years of two new experimental facilities in my laboratory (including a new wind tunnel), and the development of novel instrumentation (enabling new sophisticated measurements of which few research groups worldwide are capable), notable advances will now be possible. Moreover, the results of the above studies will answer important unresolved questions about turbulent mixing. The knowledge obtained should then be applied to technological improvements in disciplines related to energy and the environment (e.g., increased combustor efficiencies, improved governmental impact assessment models of environmental pollutant dispersion).