Tunable Porous and Patterned Surfaces for Turbulence Control
Abstract
Functional surfaces with spatially varying microstructure and porosity are common in natural flight, and increasingly prevalent in engineered systems due to advances in materials science and additive manufacturing technology. Such surfaces have demonstrated the potential to reduce skin friction, suppress flow-induced noise, modulate scalar and heat transfer, control separation, and delay transition in high-speed flows. However, our ability to realize this potential is limited by fundamental deficiencies in our understanding of the dynamic link between surface features and the near-wall turbulence, and the lack of any computationally-efficient predictive models that can guide design and optimization. The proposed effort aims to address these gaps through a combination of theoretical and experimental efforts.The theoretical effort will generate a state-of-the-art modeling framework that can rapidly predict how a specific surface treatment modifies the near-wall turbulence. Specifically, the resolvent formulation, which generates low-order representations of the turbulent flow field via a gain-based decomposition of the Navier-Stokes equations (NSE), will be extended to account for more complex surfaces through volume penalization. Key advantages of this approach include is direct link to the NSE (unlike data-driven model reduction), ability to handle complex wall geometries without regridding, and extremely low computational expense. The experimental effort will generate a high quality dataset of velocity measurements over 3Dprinted substrates with anisotropic porosity, and surface patterns of varying complexity. In addition to providing fundamental insight into the modified near-wall flow physics, these measurements will also serve as validation data for the modeling effort.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 02, 2017
- Source ID
- FA95501710142
Entities
People
- Mitul Luhar
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Southern California