DID YOU KNOW? DTIC has over 3.5 million final reports on DoD funded research, development, test, and evaluation activities available to our registered users. Click

HERE to register or log in.

# Accession Number:

## AD0810351

# Title:

## KINETIC THEORY OF THE AERODYNAMIC DRAG OF A SLOWLY ROTATING SPHERE.

# Descriptive Note:

## Technical rept.,

# Corporate Author:

## CALIFORNIA UNIV BERKELEY DIV OF AERONAUTICAL SCIENCES

# Report Date:

## 1967-01-01

# Pagination or Media Count:

##
16.0

# Abstract:

## The drag of a sphere rotating slowly inside a concentric stationary sphere is analyzed for a range of values of the mean free path in the gas filling the space between the spheres. Knudsen iteration is used to predict the drag for high values of the Knudsen number, based on the ratio used to represent the gas phase collisions. Based on this result and that appropriate for slip flows low Knudsen number two interpolation formulas are suggested to predict the drag for arbitrary Knudsen number. The predictions from these formulas agree well with available experimental data. A solution of the problem, using the moment method proposed by Lees, Leads to a simple algebraic expression for the drag which is not in such good agreement with the data. Author

# Distribution Statement:

## APPROVED FOR PUBLIC RELEASE

#