Title page for ETD etd-63097-162653

Type of Document Dissertation
Author Tyll, Jason Scott
Author's Email Address tyll@apollo.aoe.vt.edu
URN etd-63097-162653
Degree PhD
Department Aerospace and Ocean Engineering
Advisory Committee
Advisor Name Title
Deisenroth, Michael P.
Marchman, James F. III
Mason, William H.
Mook, Dean T.
Schetz, Joseph A. Committee Chair
  • ground effect aerodynamics
  • aerodynamics
  • design
  • optimization
Date of Defense 1997-07-24
Availability restricted
A multidisciplinary design optimization (MDO) methodology is developed to link

the aerodynamic shape design to the system costs for

magnetically levitated (MAGLEV) vehicles.

These railed vehicles can cruise at speeds approaching that of short

haul aircraft and travel just inches from a guideway.

They are slated for high speed intercity service of up to 500

miles in length and would compete with air shuttle services.

The realization of this technology hinges upon economic viability which is

the impetus for the design methodology presented here.

This methodology involves models for the aerodynamics, structural

weight, direct operating cost, acquisition cost, and life cycle cost

and utilizes the DOT optimization software.

Optimizations are performed using sequential quadratic programming

for a 5 design variable problem.

This problem is reformulated using

7 design variables to overcome problems due to non-smooth design space.

The reformulation of the problem provides a smoother design space which

is navigable by calculus based optimizers.

The MDO methodology proves to be a useful tool for the design of MAGLEV


The optimizations show significant and sensible differences between designing

for minimum life cycle cost and other figures of merit.

The optimizations also show a need for a more sensitive acquisition cost model

which is not based simply on weight engineering.

As a part of the design methodology, a low-order aerodynamics model is

developed for the prediction of 2-D,

ground effect flow over bluff bodies.

The model employs a continuous vortex sheet to model the solid surface,

discrete vortices to model the shed wake, the Stratford Criterion to determine

the location of the turbulent separation, and the vorticity conservation

condition to determine the strength of the shed vorticity.

The continuous vortex sheet better matches the mechanics of the flow

than discrete singularities and therefore better predicts the ground effect


The predictions compare well with higher-order computational methods and

experimental data.

A 3-D extension to this model is investigated, although no 3-D design

optimizations are performed.

NOTE: An updated copy of this ETD was added on 05/29/2013.

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