CAREER: Pulsatile Turbulent Flows over Rough Surfaces

About This Grant

Many natural and engineering flows, like wind gusts, water surges, or air moving over airplanes during maneuvers, can rapidly change speed and direction, i.e., under pulsation. These changes can be difficult to predict for flows over rough surfaces as surface protrusions create chaotic swirling and fluctuating forces in response to the shifting flow. Current prediction tools often assume smooth surfaces and steady conditions, leading to prediction errors or designs that work well in ideal scenarios but fail in real-world situations. The proposed project aims to deepen the understanding by conducting high-accuracy simulations that reveal detailed flow physics in pulsating flow over rough surfaces and develop new tools with unprecedented real-time prediction accuracy and off-design adaptability. The research will be integrated with comprehensive engagement initiatives that involve undergraduate students, community college students, and high schoolers to spark interest and cultivate skills in STEM. Outreach activities at a museum and Grade 5-12 schools will deliver accessible fluid-related STEM resources and captivating content to engage and educate the broader public. The proposed project aims to tackle the knowledge and tool gaps via three perspectives: establishing a comprehensive high-resolution dataset of pulsating rough-wall flows, discovering new physical insights via novel statistical analysis, and conducting physics-based predictive modeling. The goals are to: 1) advance the understanding of pulsatile flows over roughened surfaces and how we characterize temporal and spatial coherence of turbulent boundary layers in general; 2) develop a novel set of accurate tools to quantitatively analyze and predict roughness effects in pulsatile flows. Direct numerical simulations and large-eddy simulations will resolve the roughness-scale flow to elucidate previously unexplored flow physics with direct measurements of wall stresses and velocity within the roughness region. Three roughness categories of increasing complexity, ranging from homogeneous to multiscale heterogeneous, will be addressed. In parallel, analytical physics-based models will be developed to explicitly account for drag production by roughness. Simulations will be complemented by collaborative experiments and industrial partnerships to establish a comprehensive research chain facilitating the practical implementation of findings. The improved predictive capability will reduce the design, operation, and maintenance costs of engineered products across aviation, energy, mechanical, meteorological, and environmental industries. Education activities will broaden the participation of individuals in STEM education and research, which will promote education and career readiness, expand the talent pool, and contribute to economic development. This project is jointly funded by Fluid Dynamics program and the Established Program to Stimulate Competitive Research (EPSCoR). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.