Understanding soft-fouling and foul-releasing over non-toxic AF/FR coatings under naval operation conditions using integrated advanced numerical simulations and laboratory experiments
Abstract
The proposal aims to apply newly developed microfluidic platforms and mesoscale biofilm turbulent flow facility (Sheng, TAMUCC) in combination with advanced numerical simulation techniques (Balaras, GWU) to investigate live biofilms. We will focus on bacterial biofilm formed over new non-toxic foul releasing (AF/FR) coatings in flows, where interactions among biofilms, coating, and hydrodynamics take place over a wide range of scales spanning several orders of magnitude which are very challenging to dissect by experiments or computations alone. Our collaborative approach builds upon the strengths of each technique, where experiments measure material properties of live biofilms, and high-fidelity, fluid-structure interaction solvers utilize them to compute hard to measure quantities such as adhesion stresses and impact on standard hydrodynamic scaling laws. Teams from TAMUCC and GWU will develop tailored experimental and numerical frameworks. The former involves a multi-scale holistic approach and aims to: i) directly measure material properties and structure of live biofilms over FR coatings and their response to various flows; ii) quantify biofilm release or shear erosion processes in microscales and mesoscales; iii) enable calibration and validation of the simulations. The latter involve a multiscale modeling framework where: i) streamer resolving, direct numerical simulations capture the detailed flow structure interactions (DNS-FSI) in such biofilms to illuminate dominant transport processes and inform homogenized models, such as volume averaged Poro elastic representations (DNS-VANS) applicable to larger scale problems. Once established, these tools will be applied in a synergetic manner to understanding foul-releasing processes of biofilm over non-toxic FR coatings under high Re canonical wall flows and an adverse pressure gradient turbulent boundary layer (Re=200,000), relevant to navy applications such as propulsor and ship performance. Naval relevancy and impacts: Advance applications: Differing from prior research, we focus on obtaining a fundamental understanding of biofilm development and releasing mechanisms under realistic hydrodynamic conditions. Research on fouling over AF/FR coatings in wall flows will shed light on shear-erosion of biofilms under operational conditions and facilitate the assessment of its performance. This may lead to develop new AF/FR technologies, which is the core mission for current coating program by Dr. Armistead (Code 332). Enrich knowledgebase: Knowledge gained on foul-releasing processes in high Reynolds flows would enrich our understanding of how coatings/coated surfaces/fouls interact with wall flows. Better measurements of material properties and their responses to shear will improve our understanding of the complex interactions between soft biofilm and wall turbulence, a feedback coupling scenario that has not been sufficiently explored. Observations will provide insights into hydrodynamics over large naval surfaces & devices, which is relevant to programs directed by Dr. Young & Dr. Chang (Code 331). Build new capabilities for flow-biofilm interactions: We will develop the following new research capabilities: (i) Techniques that allow simultaneous in-situ measurements of material properties of live biofilms (e.g., viscoelasticity, creep compliance, surface adhesion) and their corresponding hydrodynamic environments. These techniques will yield large integrated datasets and unprecedented observations that would benefit ONR interests. (ii) Develop a high-fidelity simulation framework to directly resolve turbulent flow over fouled surfaces/devices. We will generate datasets that for the first time, will provide a window into the complex interactions of live biofilms and fluid flow. This abovementioned statement is approved for public release.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 06, 2023
- Source ID
- N000142312257
Entities
People
- Ilias Balaras
Organizations
- George Washington University
- Office of Naval Research
- United States Navy