# University of Minnesota

Aerospace Engineering and Mechanics

**Fall 2002 Seminar Series**

*Approximate Boundary Conditions for Large Eddy Simulation using Optimal
Control *

*Abstract*

**Near-wall resolution requirements make Large Eddy Simulation (LES)
prohibitively expensive for high Reynolds number boundary layers. Typically, to
alleviate the resolution requirement ad hoc models for the wall stresses are
used to model the effects of the unresolved near-wall flow. However, even in
turbulent channel flow, these models are often deficient. To determine if wall
stress models can be improved we pose and solve a suboptimal control problem in
turbulent channel flow. In this framework, the control is the unknown wall
stresses and the objective is to achieve the correct low-order statistics in
the interior of the flow. The solution of the control problem is used to
construct a simple, much improved, wall stress model for turbulent channel
flow.**

### Friday, November 8, 2002

209 Akerman
Hall

2:30-3:30 p.m.

### Refreshments served after the seminar in
227 Akerman Hall.

Disability accomodations provided upon request.

Contact Kristal Belisle, Senior
Secretary, 625-8000.