# University of Minnesota

Aerospace Engineering and Mechanics

**Spring 1998 Seminar Series**

*Topology of flow separation on three-dimensional bodies*

*Abstract*

### In recent years there has been extensive research on three-dimensional flow
separation. There are two different approaches: the phenomenological approach
and a mathematical approach using topology. These two approaches are reviewed
briefly and the shortcomings of some of the past works are discussed. A
comprehensive approach applicable to incompressible and compressible
steady-state flows as well as incompressible unsteady flow is then presented.
The approach is similar to earlier topological approaches to separation but is
more complete and in some cases adds more emphasis to certain points than in the
past. To assist in the classification of various types of flow, nomenclature is
introduced to describe the skin-friction portraits on the surface. This method
of classification is then demonstrated on several categories of flow to
illustrate particular points as well as the diversity of flow separation. The
categories include attached, two-dimensional separation and three different
types of simple, three-dimensional primary separation, secondary separation, and
compound separation. Hypothetical experiments are utilized to illustrate the
topological terminology and its role in characterizing these flows. These
hypothetical experiments use colored oil injected onto the surface at singular
points in the skin-friction portrait. Actual flow-visualization information, if
available, is used to corroborate the hypothetical examples.

### Thursday, May 21, 1998

227 Akerman Hall

11:30
a.m. - 12: 30 p.m.

### Disability accomodations provided upon request.

Contact
Audrey Stark-Evers, Senior Secretary,
625-8000.