Simulations of SSLV Ascent and Debris Transport

2006·8.6 MB·English

by  Rogers, Stuart

Simulations of SSLV Ascent and Debris
Transport
Space Shuttle Return-To-Flight
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Seminar in Fluid Mechanics
Stanford University
October 11, 2005 1
Outline
(cid:137)CFD simulations of
the Space Shuttle
Launch Vehicle
ascent
(cid:137)Debris transport
analysis
(cid:137)Debris aerodynamic
modeling
2
CFD Analysis of SSLV Ascent
Motivation
(cid:137) Predict air-loads on the redesigned External Tank
(cid:137) Roll maneuver air-loads
(cid:137) Debris analysis flow-fields
(cid:137) 3% Shuttle wind-tunnel test loads prediction
Approach
(cid:137) Overflow RANS flow solver
(cid:190) Central-differencing + scalar dissipation, 2nd order
(cid:190) Diagonalized approximate factorization implicit scheme
(cid:190) Spalart-Allmaras turbulence model
(cid:190) Multi-level parallelism, scalable to hundreds of CPUs
(cid:190) Use full-multi-grid sequencing to get started
(cid:137) Overset (Chimera) gridding approach
(cid:190) Developed an automated grid-generation capability
(cid:190) Gimble angles for SSME and SRB nozzles
(cid:190) Control surface deflections
(cid:190) Plume boundary-condition generation for SSMEs and SRBs
(cid:137) Validation with 3% WT model: Cp, PSP, PIV
3
CFD Analysis of SSLV Ascent
Results
(cid:137)Over 400 Overflow solutions run for Return-to-
Flight
(cid:137)New grids generated for each ascent condition
(cid:190) 2 hours on 32 Itanium-2 CPUs
(cid:190) 30 to 50 million grid points each
(cid:137)Average of ~1000 Itanium-2 CPU hrs / solution
(cid:190) ~20 hours of wallclock time running on 64 Itanium-2 CPUs
(cid:190) Never converges to a steady-state: aft end of ET,
attachment hardware, plumes, etc
(cid:190) Typically run for ~10,000 iterations
4
Geometry Details
New Grids with
New Grids without
Bipod Ramp
Bipod Ramp
Control Surface and
nozzle deflections 5
Old Grid System
“Columbia”: World Class Supercomputing
(cid:137) The NAS houses the
world’s fastest
operational
supercomputer
providing 61 teraflops
of compute capability
to the NASA user
community
(cid:137) Columbia is a 20-node
supercomputer built on
512-processor nodes
(cid:137) Columbia is the largest
SGI system in the
world with over 10,000
Intel Itanium2
processors
6
IA-700 Wind Tunnel Tests
ARC 9x7 Unitary, AEDC 16T
7
IA-700 Transonic Surface Cp –
Orbiter Wing
8
IA-700 Transonic Surface Cp –
ET
Stagnation pressure is artificially high in the
PSP data because of poor camera angles
9
Integrated Wing Loads
10
J. Greathouse/JSC