Simulation and modeling of effects of rough walls on non-equilibrium turbulent boundary layers
Abstract
The proposed research is focused on improving fundamental understanding of non-equilibrium turbulentflows close to rough surfaces, and their modeling within the framework of a structure- based, single-pointturbulence closure. Using roughness-resolved numerical simulations, we will identify the role ofroughness and its topography in modifying local and non-local turbulent structure as a result of both wallblockingand mean-distortion effects. These effects will be modeled and integrated in a structure-basedRANS model of turbulence which will capture the variation of turbulent statistics and anisotropies nearsmooth or rough walls, with arbitrary departures from flow equilibrium. To ensure that the predictivetheory accounts for various roughness regimes (e.g., ~waviness~ and ~roughness~), topographical or nearwallflow parameters that link with turbulence production and redistribution will be identified; a databaseof equilibrium and non-equilibrium wall-bounded flows will be established on systematically varied,mathematically generated topographies based on these parameters. The final year of the proposed effortwill be focused on particular non-equilibrium flows chosen in consultation with ONR, such as unsteadygust flows or flows over curved surfaces of varying roughness. This research will contribute to aconsistent theory for near-wall flows subject to various surface and flow disturbances, includingroughness, longitudinal pressure gradients (in space or time) and surface curvature, and to predictivemodeling strategies for Naval application.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 04, 2017
- Source ID
- N000141712102
Entities
People
- Junlin Yuan
Organizations
- Michigan State University
- Office of Naval Research
- United States Navy