Current Projects

• Sediment-Bed-Turbulence Coupling in Oscillatory Flows: Fully Resolved Numerical Experiments and Modeling (Funding: NSF, #1133363): Sediment transport, in rivers and coastal regions, affects large-scale geomorphic processes of dune formation, beach erosion and landform evolution that can displace human settlements, as well as destroy vegetation and agricultural infrastructure with strong socio-economic impact. In this new project we will look at quantifying effect of sediment-bed-turbulence interactions on the onset of erosion, entrainment, suspension, and deposition mechanisms of sediment. Specifically, high-fidelity numerical simulations resolving all scales of fluid flow and sediment motion will be employed to study oscillatory boundary layer dynamics and resultant sediment transport. The novelty of this research is in the development and use of a fully resolved simulation (FRS) approach based on first principles, without requiring models for drag and lift forces, for the study of sediment incipient motion. This research will also yield a Numerical Water/Wind Tunnel (NWT), a virtual educational tool for fluid-particle systems.

• High-Flux Microchannel Solar Receiver (Funding: DoE's SunShot Concentrating Solar Power Program under EERE): This collaborative project is led by Dr. M. Kevin Drost together with co-PIs Vinod Narayanan and Sourabh Apte of OSU and Bob Wegeng of Pacific Northwest National Laboratory (PNNL). The main goal of this research is to develop a microchannel solar-receiver for liquid and gas-cooled receivers. Laboratory-scale designs will be developed using integrated computational modeling for liquid-cooled systems. Focus will also be on a gas-cooled receiver design and demonstration on a solar dish at Pacific Northwest National Laboratory. It is hypothesized that use of microchannels may help reduce the size, weight, and thermal loss from high-temperature receivers owing to high heat transfer rates possible in microchannels. Goal is to first use computational modeling techniques to help guide the receiver design, build, test, and demonstrate the feasibility of the design. A novel adaptive flow-control capable of redistributing the flow with solar flux variations is also being developed by the PNNL researchers.

• Surface Transient Storage (STS) in Dead Zones of Streams (Funding: NSF, #0943570): This new project is starting in Fall 2010 and is an inter-disciplinary collaborative work between mechanical engineers and hydro-geologists (Prof. Roy Haggerty and his group). Eddies in streams caused by flow separation and recirculation can retain solutes, heat, and pollutants. The bed topology and stream conditions influence these regions. However, there is no easy or reliable method to quantify the residence time distribution (RTD) and its relation to physical characteristics such as stream velocity, size of the dead zone, and number of eddies. In this work, we are conducting field studies in Oak Creek near OSU as well as large-eddy simulation studies of turbulent flow in rivers and streams with complex bed topology. The field data will be used to validate LES results, which in turn will be used to train cheaper models based on Reynolds-Averaged Navier Stokes equations. This work will advance CFD capabilities and their applicability to hydrology and allied sciences.