# Accession Number:

## ADA465285

# Title:

## A Flexible Hypersonic Vehicle Model Developed With Piston Theory (Preprint)

# Descriptive Note:

## Conference paper

# Corporate Author:

## AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE

# Personal Author(s):

# Report Date:

## 2006-12-01

# Pagination or Media Count:

## 27.0

# Abstract:

For high Mach number flows, M 4, piston theory has been used to calculate the pressures on the surfaces of a vehicle. In a two-dimensional inviscid flow, a perpendicular column of fluid stays intact as it passes over a solid surface. Thus, the pressure at the surface can be calculated assuming the surface were a piston moving into a column of fluid. In this work, first-order piston theory is used to calculate the forces, moments, and stability derivatives for longitudinal motion of a hypersonic vehicle. The advantage of piston theory over other techniques, such as Prandtl-Meyer flow, oblique shock, or Newtonian impact theory, is that unsteady aerodynamic effects can be included in the model. The unsteady effects, considered in this work, include perturbations in the linear velocities and angular rates, due to rigid body motion. A flexible model is developed using Euler-Bernoulli beam theory and the unsteady effects due to aeroelastics are captured in the model.

# Descriptors:

# Subject Categories:

- Research and Experimental Aircraft
- Operations Research
- Fluid Mechanics
- Reciprocating and Rotating Engines