A Computational Framework for Simulating Flow around Hypersonic

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A Computational Framework for Simulating
Flow around Hypersonic Re-Entry Vehicles
David Stroh, Anthony Marshik and Gautham
Krishnamoorthy, UND Chemical Engineering
 Current challenges in computational aerothermodynamics (CA)
• Efficient generation of unstructured grids to resolve complex geometry
• Higher order discretization schemes for shock capture
• Laminar to turbulence transition models
• Reactions due to dissociation of air
• Thermodynamic non-equilibrium
• Spectral radiation
• Solid deformation due to ablation
 Long term goal: Development of add-on modules/functions and best practice guidelines
that extends the capabilities of commercial codes to study (CA) problems
 Short term goal:
• Infrastructure: Software licenses (ANSYS FLUENT, ANSYS AUTODYN)
• Sandia’s DAKOTA tool kit for uncertainty quantification
• Training of students
• Software validation of unit problems
Relevance to NASA
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•
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Directly relevant to the mission of NASA’s Division of Atmospheric and Planetary Sciences.
A hierarchial validation approach ranging from unit problems to more complex problems
Validations accomplished through comparisons against experimental data and predictions
from NASA’s in-house CA codes:
 LAURA: Hypersonic flows
 ANSYS FLUENT has additional transitional turbulence modeling options
 SAS and embedded LES options can resolve global instabilities and turbulent
structures
 Additional “vibrational temperature” transport equation will be solved
 NEQAIR: 1D line-by-line Radiative transport model (> 200,000 spectral intervals)
 2D/3D calculations in ANSYS FLUENT account for shock curvature
 Tighter coupling with fluid flow
 Speed up spectral calculations by reducing it to a few 100 intervals
 CMA, FIAT: Material response
 Tighter coupling with fluid dynamics
 Stronger deformations can be handled through the explicit solver in ANSYS
AUTODYN
Accomplishments
• Training of UGRAs
• Tasks:
 Task 1: Laminar flow over
blunt cone
 Task 2: Transitional flow over
flat plate
 Task 3: Surface heat transfer
and real gas over a sharp cone
 Backward and forward facing
steps
 Flow over Mach 20 spherical
blunt cone
 Task 4: Chemistry
 Task 5: Plasma torch problem
for Radiative heat transfer (in
progress)
Task 3
Task 2
•Newer transitional models are very promising!
•Investigating sensitivities to turbulence
boundary conditions
Spherically blunt cone
Student involvement
• Use of commercial tools speeds up the learning
process.
• Two UG research assistants (David Stroh and Anthony
Marshik) were employed full-time over Summer 2011
– They were trained on the numerical aspects of
computational fluid dynamics
– They developed a theoretical understanding of boundary
layer flows
– They developed and demonstrated extensive familiarity
with the commercial code ANSYS FLUENT
• Manuscript in preparation for submission to AIAA
Journal of Spacecraft and Rockets
Future plans for proposals
• NASA NRA – Research Opportunities in
Aeronautics
• Air Force BAA (Aerospace, Chemical and
Material Sciences) - 2012
• NSF Fluid Dynamics Program (Feb 2013)

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