Aerodynamic analysis of a modified, pylon-mounted JSOW

202 Pages·1.9 MB·English

by  Pomerantz, Boaz

NPS ARCHIVE
1997
POMERANTZ,
B.
NAVAL POSTGRADUATE SCHOOL
Monterey, California
THESIS
AERODYNAMIC ANALYSIS OF A MODIFIED,
PYLON-MOUNTED JSOW/CATM USING
MULTI-GRID CFD METHODS
by
Boaz Pomerantz
March, 1997
Thesis Advisor: Oscar Biblarz
Thesis Co-Advisor: Garth Hobson
Thesis
P7343
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March 1997 Engineer's Thesis
4. TITLEANDSUBTITLE 5. FUNDING NUMBERS
AERODYNAMIC ANALYSIS OF A MODIFIED, PYLON-MOUNTED
JSOW/CATM USING MULTI-GRID CFD METHODS
6. AUTHOR(S)
Boaz Pomerantz
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Naval Postgraduate School NUMBER
Monterey, CA 93943-5000
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13. ABSTRACT(maximum200 words)
Computational Fluid Dynamics (CFD) has become a major tool in aerodynamic analysis throughout the
aerospace industries, complementary to traditional methods such as wind tunnel testing, and analytical calculations. In this
research, an attempt was made to integrate the Similarity and Area Rules with CFD methods. Both tools, the
Similarity/Area-Rule and CFD are used to derive the characteristics of complicated aerodynamic shapes in the transonic
Mach numberregime. It was found that the Similarity Rule can only be verified qualitatively. On the other hand, the Area
Rule can be more completelyverified. The aim was to find ways to minimize the drag ofthe training configurations ofthe
Air-to-Ground (A/G) weapon, Joint-Standoff-Weapon (JSOW), in its Captive-Air-Training-Missile (CATM)
configuration. By analyzing the combination ofCATM and Pylon, itwas found that the drag ofthis configuration depends
on the average slope ofthe area cross-section distribution ofthe afterbody. The CFD tools usedwere a state-of-the-art grid
generation code, GRTDGEN, and a multi-grid integration code, PEGSUS; the configurations were run with the
OVERFLOW solver using Euler, as well as Navier-Stokes solutions. For drag optimization, Euler solutions give adequate
results, the need forNS solution can be restricted to more intensityviscous analysis.
14. SUBJECTTERMS 15. NUMBEROF
Computational Fluid Dynamics, Area Rule, Similarity Rules, Transonic flow, JSOW, CATM PAGES 169
16. PRICECODE
1R7E.PSOERCTURITYCLASSIFICATIONOF T18H.ISSEPCAUGREITYCLASSIFICATION OF A19B.SSTERCAUCRTITYCLASSIFICATION OF 2O0F.ALBISMITTRAATCITON
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AERODYNAMIC ANALYSIS OF A MODIFIED,
PYLON-MOUNTED JSOW/CATM USING
MULTI-GRID CFD METHODS
Boaz Pomerantz
Major, Israeli Air Force
BS Aeronautical Engineering., Technion, Israel, 1986
Submitted in partial fulfillment ofthe
requirements for the degree of
AERONAUTICAL AND ASTRONAUTICAL ENGINEER
from the
NAVAL POSTGRADUATE SCHOOL
March 1997

DUDLEYKNOXLIBRARY
MI£OYN*TELrRfE0YSTCGARA9D3U5A4T3^E1S01CHOOL
ABSTRACT
Computational Fluid Dynamics (CFD) has become a major tool in aerodynamic
analysis throughout the aerospace industries, complementary to traditional methods such
as wind tunnel testing, and analytical calculations. In this research, an attempt was made to
integrate the Similarity and Area Rules with CFD methods. Both tools, the
Similarity/Area-Rule and CFD are used to derive the characteristics of complicated
aerodynamic shapes in the transonic Mach number regime. It was found that the Similarity
Rule can only be verified qualitatively. On the other hand, the Area Rule can be more
completely verified. The aim was to find ways to minimize the drag of the training
configurations of the Air-to-Ground (A/G) weapon, Joint-Standoff-Weapon (JSOW), in
its Captive-Air-Training-Missile (CATM) configuration. By analyzing the combination of
CATM and Pylon, it was found that the drag ofthis configuration depends on the average
slope ofthe area cross-section distribution ofthe afterbody. The CFD tools used were a
state-of-the-art grid generation code, GRIDGEN, and a multi-grid integration code,
PEGSUS; the configurations were run with the OVERFLOW solver using Euler, as well
as Navier-Stokes solutions. For drag optimization, Euler solutions give adequate results,
the need for NS solution can be restricted to more intensity viscous analysis.
VI
..
TABLE OF CONTENTS
INTRODUCTION
I. 1
BACKGROUND
H. 3
JSOW WEAPON SYSTEM
A. 3
B. JSOW TRAINING POD - CATM AND THE NAVAL
POSTGRADUATE SCHOOL TEAM INVOLVEMENT
4
C. CFD - COMPUTATIONAL FLUID DYNAMICS AS A
DEVELOPMENT TOOL USED IN THE PROCESS 5
1 Overview 5
2. Competitive Methods 6
THEORETICAL BACKGROUND
D. 6
1 General 6
2. Navier Stokes (NS) Equations And Solution Techniques .. 7
m. COMPUTATIONAL TOOLS AND TECHNIQUES
11
ARCHITECTURE
A. 11
GRIDGEN
B. 12
1. General 12
2. Theory 13
3. Difficulties 16
C. PEGSUS 23
1. General 23
2. Chimera Method 23
3. Technique 25
4. Orphan Points 25
5. PEGSUS Output 27
VII
OVERFLOW
D. 28
1. General 28
2. Technique 28
3. Useful Suggestions 30
E. FAST 30
GRIDED
F. 31
RMG2PEG
G. 32
H. MERGE41 32
I. XB2A.F, XA2B.F - BINARY TO ASCII AND ASCII TO BINARY
CONVERSION FILES 34
READFOMO.M, READRESID.M 34
J.
WRQ
K. 35
WRGR
L. 35
IV TEST CASE CONFIGURATION 37
GENERAL
A. 37
THE MODELS
B. 37
OVERFLOW
C. 40
CFL, DT and Convergence 40
1.
2. GRID Topology 40
CONVERGENCE
D. 41
V JSOW/CATM BODY CONFIGURATION 43
A. GENERAL 43
B. GRID GENERATION 46
Methodology 46
1.
2. Grid Lines Distribution 46
C. FLOW ANALYSIS 49
Vlll