Military Vortices
Abstract
The flow control methods being exploited by Micro-electro-mechanical systems (MEMS) devices rely in many cases on the manipulation of small-scale vortices to provide favorable mixing effects. By appropriate design and siting of MEMS very local effects on the flow can be made to provoke large-scale changes in the flow structure and, for example, control the conditions at which the flow separates. This topic area will not be considered further in this paper, but results from current research indicate that military organizations should derive large potential benefits from this technology when it reaches maturity. The remainder of the paper will consider larger-scale separated flows of a vortical nature, which may be steady or time-dependent. In this keynote address, the author reviews the wide range of vortex flows that occur on military vehicles and classifies them into three categories: those designed into a vehicle to improve performance, those that cannot be avoided and whose deleterious effects must be minimized, and those that were not expected to occur. Examples of vortex-flow effects on air and sea vehicles and in propulsion systems are cited to illustrate these categories. It is concluded that vortex flows are all-pervasive and can have major effects on the operation and performance of military vehicles. With the trend to increased diversity in shape for future vehicles it is essential to continue to improve knowledge of and predictive capability for vortex flows. Sections of the paper discuss vortex flows in relation to aerodynamic lift, aerodynamic control surfaces, drag reduction, internal flows in combustion chambers, body vortices, wing vortices, junction effects, chine vortices, intake lips and diverters, ground vortices, vortex wakes, fin buffeting, rear fuselage vortex separations, failure cases, rotorcraft, vehicle build quality and inservice degradation, sea vehicles, and future military vehicles. (23 figures)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2003
- Accession Number
- ADA419065
Entities
People
- D. A. Lovell