Wall Turbulence Response to Large scale Surface Heterogeneity: Physics based Wall Models Derived from Coordinated Experiments and Simulations
Abstract
The physics of wall turbulence – ducts, boundary layers, and pipes – affects the aerodynamic signature of an array of Department of Defense (DoD) vehicles. Such flows often occur under the “fully rough”, inertial dominated limits for which viscous effects can be readily neglected and skin friction is driven by form drag (i.e., turbulent mixing). Rough surfaces composed of a complex height distribution are common on the aerodynamic surface of DoD vehicles. Prognostic flow description is confounded by the presence of large scale heterogeneity in surface geometry: that is, “patches” of differing roughness type, with spatial extent at least equal to the depth of the flow (i.e., duct half height, pipe radius, or boundary layer depth). When the prevailing transport direction is aligned orthogonal and parallel to such a heterogeneity, the flow responds with formation of an internal boundary layer or with counter rotating rolls, respectively. These surface driven secondary flows completely disrupt the outer layer dynamics, and thus have direct implications for wall modeled large eddy simulation predicated upon outer layer content. Moreover, realizations of precise orthogonal-parallel alignment are expected to be rare, and oblique alignment is likely the norm (for example, during vehicle maneuver).
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 14, 2022
- Source ID
- FA95501910134
Entities
People
- William E Anderson
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Texas at Dallas