An essential process in many industrial systems is the transfer of heat from a surface to a flowing fluid stream with a minimum dissipation cost. As a result of the critical role that efficient heat transport plays in applications, several heat transfer enhancement techniques have been devised in the past. A common form of transport enhancement is flow destabilization via cylindrical eddy-promoters placed inside a channel. Previous studies suggest that appropriate destabilization of the flow in the laminar regime results in increasing transport rates up to 500 percent. In this work, the transitional and turbulent flow regime, mostly encountered in engineering practice, will be studied. Destabilization should be applied at the naturally stable scales of motion, i.e. excitation of the -near-the-wall viscous sublayer. The work will include both Direct Numerical Simulation (DNS), as well as companion detailed experiments. The numerical simulations are based on spectral element methods that combine high-accuracy, as well as flexibility in handling complex geometries. The experiments are chosen to allow a maximum overlay with the numerical data in measuring time lines and fluid particle paths of velocity and temperature fields. Experimental techniques include flow visualization via hydrogen bubble, schlieren photography, and laser-sheet scanning techniques. The research will have a direct impact on the development of innovative heat exchanger systems. At the same time, it will underline the potential of DNS as a very powerful tool in gaining deep understanding and obtaining detailed results for transport processes. The companion experiments will provide a basis for the validation of the computations.
