The goal of the proposed research is to improve our theoretical understanding and modeling of turbulent flow close to a solid object, which is the most important and relevant to engineering applications class of turbulent flows (since turbulence found in industrial processes, aerospace and naval applications, and in the atmospheric boundary layer fall within this class). A new experimental technique for measuring velocity fluctuations at resolutions that are one order of magnitude finer than currently available techniques is also proposed.
Because of the complexity of turbulent flows, it is very challenging to obtain high quality experimental data and to conduct high fidelity numerical simulations at the scales and resolutions that have practical interest and that are needed to validate theoretical advances. Detailed studies have often been replaced with simple parameterizations and correlations. Simple analogies between momentum transfer and heat transfer have been the foundation for most turbulent heat transfer models, even if it is well-known that these analogies perform poorly in many applications. While significant breakthroughs have taken place in the last twenty years, there are still limitations in current instrumentation and high Reynolds number studies have often been limited to measurements of only one component of the velocity vector. This is where the contribution of the proposed work is: it proposes a study of turbulent transport over a wide range of Reynolds numbers. It is proposed to overcome experimental limitations by deploying novel MEMS-based flow sensors. By combining the proposed novel instrumentation with a heated pipe-flow facility, unprecedented multi-component velocity and temperature data are expected to be obtained in a unique facility, the Princeton Superpipe, at extreme Reynolds numbers. In addition fundamental theoretical work will be conducted to integrate the study of turbulent heat transfer with turbulent momentum studies. Results from this work, if successful, has the potential to increase the capabilities of laboratory setups across the world. Educational and outreach activities that include graduate and undergraduate students, and restructuring of undergraduate lab courses are proposed. Activities of the project will find leverage from an existing REU program at Princeton.
