Governing differential equation, boundary conditions for the analysis on which computer program is based, and method of solution of resulting finite difference equations are discussed in the documentation

Howser, L. M.

Tompkins, S. S.

English

Computer program for analyzing transient response of ablating axisymmetric bodies including effects of shape chang

NASA Technical Reports Server

Computer program for the transient response of ablating axisymmetric bodies including the effects shape change

1972	 B72-10068 
.
NASA TECH BRIEF 
Langley Research Center 
NASA Tech Briefs announce now technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Program for the Transient Response of Ablating Axisymmetric Bodies

Including the Effects of Shape Change 
The problem: 
To perform calculations and to analyze the transient 
response of an ablating axisymmetric body, including 
the effects of shape change. 
The solution: 
A computer program has been developed to analyze 
the transient response of ablating axisymmetric bodies 
including the effects of shape change. 
How it's done: 
The governing differential equation, the boundary 
conditions for the analysis on which the computer 
program is based, and the method of solution of the 
resulting finite-difference equations are discussed in the 
documentation. 
Some of the features of the analysis and the asso-
ciated program are: (1) the ablation material is con-
sidered to be orthotropic with temperature-dependent 
thermal properties; (2) the thermal response of the 
entire body is considered simultaneously; (3) the heat 
transfer and pressure distribution over the body are 
adjusted to the new geometry as ablation occurs; 
(4) the governing equations and several boundary-
condition options are formulated in terms of gener-
alized orthogonal coordinates for fixed points in a 
moving coordinate system; (5) the finite-difference 
equations are solved implicitly; and (6) other instan-
taneous body shapes can be displayed with a user-
supplied plotting routine. 
The physical problem to be modeled with the 
analysis is described by FORTRAN input variables. For 
example, the external body geometry is described in
the W,Z coordinates; material density is given, and the 
stagnation cold-wall heating rate is given in a time-
dependent array. Other input variables are required 
which control the solution, specify boundary conditions, 
and determine output from the program. The equations 
have been programmed so that either the International 
System of Units or the U.S. Customary Units may be 
used. 
Calculations from this program may be saved for 
plotting purposes, but the user will have to supply his 
own plotting routines. 
Notes: 
1. This program is written in FORTRAN IV to be 
utilized by the CDC-6000 Series computers. If plots 
are desired, a plotter is required along with user 
supplied plot routines. 
2. Submitted by: Lona M. Howser 
Stephen S. Tompkins 
Langley Research Center 
Hampton, Virginia 23365 
(LAR-1 1049) 
3. Inquiries concerning this program should be directed 
to:
COSMIC 
112 Barrow Hall 
University of Georgia 
Athens, Georgia 30601 
Category 09 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
..
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Program for the transient response of ablating axisymmetric bodies including the effects of shape change

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